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Green Concrete: The Foundation for a Sustainable Home
CategoriesSustainable News Zero Energy Homes

Green Concrete: The Foundation for a Sustainable Home

By Zarkon Group,

Concrete, the most widely used construction material on the planet, has a serious pollution problem. Accounting for about 7% of carbon emissions per year (approximately 2.8 gigatons of CO2), if concrete were a country it would rank third behind China and the United States in terms of total emissions. Concrete, used to construct roads, bridges, homes, and monuments for centuries, needs to change to mitigate the effects of climate change. Fortunately, a variety of new, green concrete options are emerging to lower the embodied carbon of homes and buildings and help achieve global climate goals.

Concrete carbon emissions come from cement

Concrete is made of cement, water, and aggregates (such as crushed stone, sand, and gravel), as well as chemical admixtures to increase durability, workability, or resilience to environmental factors.

The cement is usually made of clay, limestone, or iron ore and serves as the main binder of concrete. Portland cement, the most common type of cement, forms by heating limestone and clay to blistering temperatures, which produces clinker—a dense, hard substance that’s then ground into a fine powder to form cement. This formation process is extremely energy intensive and requires the burning of coal, oil, and other fossil fuels. Additionally, when limestone is heated, it produces quicklime, releasing CO2 as a byproduct. Altogether, this produces the equivalent of 0.98 tons of CO2 per ton of clinker, of which 0.46 tons are attributable to fuel combustion (source: EPA 2010). That’s gigatons of carbon emissions annually!

Reference

Home EV Charging Made Simple (But Do Hire an Electrician)
CategoriesSustainable News Zero Energy Homes

Home EV Charging Made Simple (But Do Hire an Electrician)

By Zarkon Group,

Level 2 is fine for home EV charging

All electric vehicles, except Teslas, use public and private L-2 chargers via a J1772 connector, also known as the J-plug. (Tesla vehicles come with the adapter that lets you use the J-plug.) An L-2 charger will typically take about 4-10 hours to fully charge an EV. For home EV charging, that usually works.

“Eighty percent of EV charging is done at home anyway, and they charge overnight,” Myers added. “The average mileage that an EV driver drives is around 30 miles a day. People really don’t need to go in and do a super-quick fill up at home.… You don’t run your cell phone until it’s completely empty and then run to go charge again. You use it during the day, and at night you plug it in and then it charges. That’s really how EVs are run. So we kind of have to get into that mentality [with our cars].”

Public DC fast chargers

Even so, sometimes we need a quick charge to get us home. “Where these [DC] fast chargers come in is along major highways, because that’s where you do need it if you’re traveling from here to here: to provide that 15-minute, half-hour stop,” Myers said. “You get some coffee or whatever, fill up and then be on your way.”

FYI: there are three types of DC fast chargers: CHAdeMO, CCS, and Tesla. Again, you’ll find these DCFC stations in public, but not for home EV charging.

  • CHAdeMO (the initialism for charge de move is pronounced CHAD-em-oh) has become the standard for manufacturers like Nissan and Mitsubishi.
  • The more common CCS, or combined charging system, is an open-source standard. In the US, all newly manufactured passenger EVs (except Tesla) will use the CCS connector.
  • Tesla vehicles utilize their own DC fast chargers, but vehicles come with adaptors for CCS.

Reference

Decarbonize Your Home to Support a Greener Grid
CategoriesSustainable News Zero Energy Homes

Decarbonize Your Home to Support a Greener Grid

By Zarkon Group,

Solar supply and residents’ demand

California already has a great deal of solar electricity being generated, both on buildings and in large-scale solar farms. For example, years of Prop 39 projects for school districts around California have been completed, installing megawatts of solar farms on campuses. These sites were targeted, in part, due to lower summer occupancies, and net metering rules allowed them to reap large financial benefits. Most of these campuses are net exporters of clean renewable energy all summer long. Every day, the managers of the electrical grid must stabilize local electric networks to share this abundant load throughout the day, and quickly ramp up centralized power once the sun goes down and folks head home.

As more all-electric buildings and homes come online, it is important to look at the impacts of these buildings on grid health. The grid must continue to be updated to guard against solar saturation: where solar generation exceeds the total usage in a given area. The grid is managed by local utilities and state agencies, and this balance of supply and demand drives time-of-day pricing that encourages responsible usage.

Energy industry experts point to what is known as the “duck curve,” the risk of over-generation of renewable energy (especially solar) and the impact of having to ramp up energy production (most often these are natural gas plants) to respond to rising demand when the sun goes down. In the belly of the duck (the middle of the day), solar production is peaking and electricity sells at a loss. Yes, California is paying other Western states to take solar energy off their grid. This lets baseload generation systems like nuclear, hydroelectric, and some natural gas plants run constantly, as they cannot easily, or cost-effectively, shut down and then come back on daily.

Reference

Calif. Embraces Passive House for Zero Carbon Multifamily Housing
CategoriesSustainable News Zero Energy Homes

Calif. Embraces Passive House for Zero Carbon Multifamily Housing

By Zarkon Group,

The housing crisis in California is leaving thousands unsheltered and millions more with high rent burdens, threatening low-income communities, who are disproportionately people of color. Meanwhile, the climate crisis is causing wildfires, dangerous air quality, and widespread power shut-offs. A recent study funded by the California Public Utilities Commission highlights how Passive House (PH) design principles should be utilized in new construction to create zero carbon multifamily housing and contribute to more comfortable, healthy, and safe buildings for residents.

The Advancing Options for Decarbonization in Multifamily Buildings study developed by BluePoint Planning will inform the state’s zero-carbon program for new multifamily construction, and is designed to shape future California Energy codes (Title 24 part 6). The intention is to reduce greenhouse gas emissions from multifamily buildings, promote occupant safety and comfort, and provide greater resilience in the face of climate change and extreme weather.

The study promotes deep energy efficiency practices and encourages market actors to go beyond code, by integrating ultra-efficient PH approaches in the design and construction of new zero carbon multifamily housing. Passive House design elements emphasize airtight construction, reduced thermal bridging, and passive daylighting, heating, and cooling as much as possible.

Why Passive House?

Building on stakeholders’ and technical advisors’ input, the study highlights that PH in multifamily buildings is cost-effective and is one of the best building sectors to focus on. PH buildings can use up to 80% less energy than existing standard construction, and 20% less energy than current California energy code. The PH model has been around for more than 40 years and can be applied to all building types—including multifamily residential and mixed-use commercial and multifamily. The technique has become popular throughout Europe, while gaining ground in the United States as well, with the square footage of PH buildings more than doubling every 2 years over the past decade. Today, there are more than 100 multifamily Passive House buildings in the US, equaling more than 2.7 million square feet; though there are few in California.

PH construction relies on a  well-insulated building envelope that minimizes air leaks and thermal bridging, to create an ultra–energy-efficient building. Other elements such as double- and triple-paned, properly installed windows are also needed to achieve proper insulation. The resulting energy efficiency and reduction in demand is critical to meet California’s climate goals, to support the electrical grid, and to lower costs to ratepayers.

Smiling adults socialize and dine on outdoor patio, amid attractive plantings

Building systems and beyond

Zero carbon multifamily buildings must be all-electric, utilizing efficient heat pump HVAC and heat pump water heaters. Note that the elimination of natural gas infrastructure helps reduce construction costs. Did you know that that plug loads consume 30% to 44% of whole building energy for multifamily buildings (depending on climate zone), because each unit has less space to be heated and cooled but still uses roughly the same number of appliances? Thus, highly efficient appliances will have high impact in reducing energy consumption. Consider induction cooktops, heat pump clothes dryers, and ENERGY STAR rated or other third-party certified microwaves, dishwashers, clothes washers, and refrigerators. In addition, the study requires that operation and management of multifamily buildings actively reduce emissions associated with energy use.

The study expands the discussion beyond the building’s systems and considers siting, connection to other buildings, and potential for scaled infrastructure. Proper site design, orientation to the sun, and site shading all affect the need for heating and cooling. When done correctly, these elements work in tandem with airtight insulation to maintain comfortable indoor temperatures with minimal active heating and cooling.

Solar battery storage for resilience

Solar and storage are also critical elements to creating low carbon, resilient buildings. Once a multifamily building approaches ultra-low energy use intensity (EUI) targets, solar and storage must be integrated to help satisfy the building’s daily energy demands and to support basic electricity needs during a power outage. For multifamily properties, it’s essential to consider rooftop configurations and availability, and to enable siting solar over parking areas or other parts of the site. The decarbonization study also covers integration of electric charging stations and vehicle-to-grid technologies that can help to raise the overall benefits of a zero carbon building and its resilience.

Passive House design is known best as helping to create high-performing buildings and reducing energy use. However, key elements like insulation, energy efficient appliances, and solar with battery storage, can have invaluable resilience benefits in a world where climate change impacts are becoming more extreme and life-threatening.

Resilience and equity in zero carbon multifamily housing

The study considers equity as an essential principle, and advocates that PH buildings provide a durable sanctuary for residents in the face of disaster, extreme weather, or smoke from wildfires. (Durable sanctuary refers to a home or building that ensures a safe and healthy living space for its occupants both every day and during emergencies, including power outages for multiple days.) This is particularly important for disadvantaged populations who are more likely to have increased vulnerability to climate threats and are more likely to experience health complications from such an event.

One study showed that PH buildings can maintain a sufficient indoor temperature in the case of a power shut off in the extreme cold for over 6 days, compared to traditionally designed buildings, which only stay comfortable for about 1 day. The potential for Passive House as a resilience tool and mechanism to promote safety and potentially life-saving services in the face of disaster is ready to be realized.

Residents wal and socialize in courtyard of sustainable affordable housing development

The Advancing Options for Decarbonization in Multifamily Buildings study can be considered a reference point for where the housing industry in California is headed. As such, it can act as a tool for design and construction professionals in California to help align their industries towards Passive House standards and more climate-friendly and resilient multifamily buildings. This includes promoting and expanding relevant training, aligning energy modeling tools, and advocating for resilience standards and certifications in their projects.

Bianca Hutner has a background in climate policy advocacy and local government climate planning. At BluePoint Planning, she helps California local jurisdictions reduce emissions and promote resilience through climate planning efforts and assists in regional and statewide efforts to curb climate change and promote an energy-resilient future. Hutner is a co-author of the Multifamily Zero Carbon Action Plan for the California Public Utilities Commission.

Reference

DOE Targets Air Leaks in Path to Zero Carbon
CategoriesSustainable News Zero Energy Homes

DOE Targets Air Leaks in Path to Zero Carbon

By Zarkon Group,

The Department of Energy released the residential segment of the U.S. Building Stock Characterization Study to give decisionmakers a science-based tool to identify technologies and solutions to drive the US housing stock toward zero carbon operation. The National Renewable Energy Laboratory, with input from the Advanced Building Construction Collaborative led by the Rocky Mountain Institute, developed the benchmark survey and accompanying dashboard. Typology studies like this have valued precedents in other countries, particularly in Europe, but this is the first-ever, national-level study of the US housing stock.

Updated in 2022 to include commercial buildings, the analysis segmented the US housing stock into 165 subgroups based on climate zone, wall structure, housing type, and year of construction. For each segment, thermal energy use (i.e., energy used for HVAC and water heating) was analyzed by end-use and segment. This gives policymakers and business owners insight to prioritize specific regions, housing segments, and target technologies for efficiency and electrification upgrades.

Primary high-level takeaways

Single-family detached homes

Not surprisingly, most residential thermal energy use is in single-family detached homes, which constitute the majority of residential buildings in the US. Single-family detached homes also have the highest thermal energy end-use per square foot (energy intensity); plus the largest square footage per home. This one-two punch means that any zero-carbon strategy must address this sector and its complex ownership structures, small individual building sizes, and diverse architectures.

Air leakage

Air leakage (infiltration) is the primary driver for heating loads in every climate region studied. For example, in multifamily buildings in cold climates, air leakage is nearly double all other envelope heat transfer component loads combined. This prioritizes insulation and other air-sealing strategies—especially those that limit disruptions for occupants during renovations. More research is needed on panelized walls, drill-and-fill insulation, and window retrofits to prove their effectiveness. Reducing air leakage, combined with mechanical ventilation, could also provide additional, non-monetary benefits for occupants, such as better thermal comfort, reduced moisture, and improved indoor air quality.

Mobile Homes

Mobile homes are extremely energy-intensive. Despite comprising a relatively small share of total housing units in most climate regions (around 4% to 9%), mobile homes typically have much larger thermal energy consumption per square foot than other building types. This inordinate energy intensity increases in older mobile homes in cold or mixed climate regions, where oil and gas heating are common; but is also problematic in hotter climates, where electric heating and cooling dominate.

Retrofitting mobile homes will likely offer an array of benefits for occupants, starting with reduced energy bills. Often, this might entail replacing the unit completely, although there could be significant barriers, such as local codes, taxes and ownership structures, as well as potential equity implications of displacing occupants.

Electrification

Fossil fuel–based space and water heating must be replaced to achieve decarbonization. These are the largest contributors to energy intensity and total loads. Again, electrification is needed across the US, in colder climates where oil and gas space and water heating are most common, and warmer regions with less reliance on fossil fuels. By benchmarking the different segments, the study informs decision-makers on where existing technologies are cost-effective, and where additional incentives or other cost reductions might be needed. (The DSIRE database is a great place to easily search and find a wide variety of state and federal financial incentives for sustainable new construction and renovations.) Some housing segments may also require envelope retrofits, to make electric heating pencil out, such as in the cold Northeast and Mid-Atlantic regions.

Solutions work across segments

The good news is that retrofit and building solutions are largely transferable among different residential segments. For example, energy efficiency packages developed for single-family detached, midcentury wood frame construction (which is the single-family segment with the highest thermal energy use in three of the five climate regions) will likely be applicable to other segments, such as other wood frame single-family detached vintages, as well as low-rise, wood frame multifamily buildings. Similarly, solutions developed for Marine-climate multifamily buildings, where water heating is the largest energy end use, could potentially apply broadly, as water heating retrofits aren’t impacted by the existing envelope.

Next steps to zero carbon

Local policymakers and building professionals should check out the free online dashboard that accompanies this report. Deep dive to explore building characteristics by specific state or county, examine nonthermal energy use, explore detailed HVAC configurations, and more. The online dashboard can serve as a baseline for the development of local efficiency and decarbonization strategies; and inform businesses on local opportunities. The commercial building recommendations and dashboard are also worth exploring.

In addition, this comprehensive, building characterization study will directly support technology and development goals nationwide, and further the work of the Advanced Building Construction Initiative as they explore avenues toward better performance and zero carbon. Beyond the major takeaways above, the ABC Analysis Working Group will identify additional home segments and strategies to prioritize for high decarbonization impact. And then model individual and packaged upgrades appropriate for particular segments.

Reference

Electrifying? You May Not Need an Electrical Panel Upgrade
CategoriesSustainable News Zero Energy Homes

Electrifying? You May Not Need an Electrical Panel Upgrade

By Zarkon Group,

The growing number of homeowners seeking to abandon gas and oil and electrify their older homes are bringing newfound attention to electrical panels. These oft-forgotten metal boxes in the wall of your garage, basement, or other out-of-the-way space form a choke point for electrification, nationwide. Will you need a full electrical panel upgrade to meet your home’s increased electric demand?

“Many people don’t even know where their electrical panel is, and now it’s become one of the most important players in the whole electrification conversation,” said Brian Stewart, Co-Founder of Electrify Now. “The electrical panel is the unsung hero of the electrification project.”

Electrification—switching from gas and oil to all-electric appliances and heaters—will cut CO2  and other emissions, but it will likely increase your home’s electrical energy consumption. Watch out, because your electrical panel has a hard cap on how much electricity it can deliver to your house; how many amps at once. If you live in a home less than 50 years old, there’s a good chance you have a 200 A electrical panel that’s more than capable of handling these bigger electrical loads. But what if you live in an older home with a 100 A panel?

Let’s look at a typical energy load for an all-electric house and break down the range of options available if your electrical panel needs some help to meet the increased energy demand.

The basics

An electrical panel, also called a breaker box or circuit panel, is responsible for safely delivering electricity from the utility’s power lines to your home and then distributing loads throughout. A single, large switch controls the main breaker, turning your entire home’s electricity on and off. The row or two of smaller breakers circuit to different appliances, lighting zones, and areas.

You can tell how many amps of service your panel receives by

  • Inspecting the utility’s meter box (outdoors) for a label with an amperage rating
  • Inspecting your electrical panel for a label with its amperage rating
  • Checking the size of the main breaker on the panel

Do you need electrical panel upgrades?

To electrify your home, you may or may not need more electricity. “Over half of homes in the US have electrical service less than or equal to 100 amps,” explains Cora Wyent, Research Associate for Rewiring America. Let’s consider how that compares to a typical power load in an all-electric home:

  • Lighting and plugs: 6 kW
  • Electric vehicle (EV) charger: 10 kW
  • Electric cooktop and oven: 10 kW
  • Electric dryer: 5 kW
  • Heat pump water heater: 5 kW
  • Dishwasher, microwave, and other appliances: 1.5 kW each

Wyent calculated that running electricity to everything on that list would require around 121 A. So, if you have a 100 A electrical panel, you likely need to undertake some sort of upgrade to electrify:

  1. A full electrical panel upgrade and/or upsize of utility service
  2. Panel optimization
  3. Deploy technology, like smart panels, to manage your electrical load

1. Service upsize and electrical panel upgrade

To increase your home’s energy cap, you’ll need to upgrade your electrical panel, rewire it to increase the service you get from your utility, or both. This process can cost anywhere from $2,000 to $30,000 and take up to 6 months. Yikes! The Inflation Reduction Act offers rebates and tax credits to help offset the cost, but it’ll still be an expensive, time-consuming process.

“Sometimes upgrading and upsizing are unavoidable, but most homes with a 100 A circuit breaker have faster, safer, and more affordable options for electrifying their homes,” said Hannah Bruegmann, Director of Programs at Build It Green. “They’re just not as common because not enough people are familiar with the available options.” Even in older homes, you may not need a full electrical panel upgrade.

2. Panel optimization

“Panel optimization can help people electrify existing homes as quickly, cost-effectively, and equitably as possible,” Bruegmann says. In homes with 100 A panels or greater, you can often avoid a full utility service and electrical panel upgrade by optimizing the panel, through appliance choice and whole-home electrification planning. To do this, you’ll need to combine power-efficient appliances with circuit-sharing devices to manage your home’s energy use.

Not only does panel optimization save money compared to service upgrades, it also keeps the additional pressure off your local utility’s grid. And those same rebates and tax credits available for electrical upgrades often apply to energy-efficient appliances too. Upgrading to efficient appliances that draw less power makes optimization more feasible, effective, and comfortable.

Panel optimization strategies

“Even at peak use, most homeowners only utilize approximately 30% of their available electricity,” Bruegmann explained. So optimizing your panel may be easier than you think. Some strategies to manage your electrical load include

  • Selecting power-efficient appliances—they’re often nearly identical to less efficient models in cost and performance.
  • Air sealing your home to reduce heat and cooling losses.
  • Avoiding oversized EV chargers.
  • Pausing EV charging when other power-intense appliances, such as the washer and dryer, are running. You can do this manually or with a prioritized circuit-sharing device.
  • Selecting appliances that combine two functions, like a cooking range and oven, reducing the need for separate high-power circuits.

 

Span’s smart electrical panel provides monitoring and controls for all circuits plus flexibility for battery backup during power outages.

3. Smart electrical panel upgrades

A growing number of devices can help with panel optimization, including load-sharing devices, meter collars, smart circuit breakers, smart panels, and sub-panels. These tools can manage your electricity demand and avoid exceeding the overall energy supply (100 A) and the draw on specific circuits.

“Electrification can stress a home’s infrastructure,” explained Chad Conway, Head of Products at SPAN, a smart-panel manufacturer. “Intelligent load management can address the infrequent instances of high demand, automatically managing energy use in real time and saving the homeowner thousands of dollars compared to the cost of a [utility] service upgrade.”

With smart panels, smart circuit splitters, and other high-tech panel add-ons, you can prioritize electrical loads for each circuit. When the circuit reaches a certain draw, the technology will avoid overloading by shutting down the load designated with lowest priority. “This technology really enables a more efficient use of both the infrastructure in your home and the infrastructure on the grid,” Conway says.

A popular example is a shared circuit between an EV charger and an electric clothes dryer. The EV charger automatically pauses when you turn the dryer on, and then resumes charging when the dryer finishes. Unless you’re running laundry all night, your car will still be charged for your commute by the morning. No expensive electrical panel upgrade necessary!

Smart tech that prioritizes loads is also advisable if you plan to use solar panels and a solar battery system to power your home during an outage. You might also be able to take advantage of your utility’s time-of-use rates, or a demand-management rate, on a regular basis. These controllers offer user-friendly dashboards or apps to control your power balancing during emergencies or other special circumstances.

Electrify everything

“To hit our climate goals and reduce human environmental harms, we need to transition from natural gas to electric power as quickly, equitably, and cost-effectively as possible,” emphasized Bruegmann. Sometimes, electrical panel and service upgrades are unavoidable. But, many homes with 100 A electrical panels can electrify quickly and affordably via panel optimization, energy-efficient appliances, and power-managing technology.

Note: This article springs from Electrify Now’s webinar on “Electrical Panel Upgrades.” For more strategies and technologies to electrify your home, visit their YouTube Channel.

By Catherine Poslusny

Reference

Embodied Carbon: Reduce Your Home’s Hidden Carbon Footprint
CategoriesSustainable News Zero Energy Homes

Embodied Carbon: Reduce Your Home’s Hidden Carbon Footprint

By Zarkon Group,

Operational carbon is usually what we think of when energy costs are discussed. That is, carbon emissions that come from the energy used to power our homes, cars, etc. over their lifetime. Your home’s energy efficiency comes into play here. Generally, operational carbon emissions can be modeled and predicted, so you can compare one appliance or building product against another. Often, a label will show how much energy a certain appliance is likely to draw over a lifetime of operation, or how much a well insulated house will reduce your energy needs annually. But embodied carbon takes this modeling to a whole ’nother level.

Embodied carbon is the carbon footprint of a product, process, or service starting with the extraction of raw materials through the manufacturing process to market (cradle to gate) and then beyond to delivery and installation (cradle to site). Operational carbon is often considered separately, but adding the carbon embodied in a product’s end-of-life disposal (cradle to grave) or reuse or recycling (cradle-to-cradle) gives a complete lifecycle analysis. In other words, embodied carbon represents the total amount of greenhouse gases (including CO2) emitted during extraction, transportation, manufacture, delivery and deployment, and then end-of-life. Looking at both the embodied carbon and the operational carbon give you the true “carbon cost” of your product or project.

Let’s picture a new countertop for your kitchen. The embodied carbon of that countertop that you will enjoy in your home comprises the energy that goes into mining the stone, transporting the raw material from the mine to a facility for processing, its processing and preparation (cutting, strengthening, and polishing), transporting to a wholesaler, and then to your home where we include the energy emissions of cutting to size and setting it up in your kitchen. And finally its end-of-life, which hopefully includes reuse or recycling wherever possible.

Hardware store assortment, shelf with stainless steel mortise sinks, nobody. Building materials and tools choice in diy shop, rows of products on racks

Embodied carbon hides in your home

For homes, the biggest sources of embodied carbon are typically in materials. Many common materials used in construction, such as concrete, stone, steel, and lumber, tend to be high in embodied carbon either due to energy-intensive extraction or manufacturing processes. Even products made from rapidly renewable materials, or by a manufacturer that uses renewable energy, may waste a lot of water, or raw or finished materials. Or the product must travel overseas, or lasts only a short time before it heads for the landfill and must be replaced.

An exception to looking for the lowest carbon equation would be if the building materials are used for carbon sequestration. For instance, natural renewable materials such as wood from sustainable forests, or wool, or bamboo will hold carbon safely within the walls and furnishings of your home, while the natural source is replenished and continues to grow and pull more carbon from the atmosphere.

To reduce the embodied carbon in your home, as the saying goes, you can’t manage what you don’t measure. The most accurate analysis of the embodied carbon in extraction, transportation, and manufacturing is going to come from the product manufacturer. Eco-conscious companies often use environmental product declarations (EPDs) and post the data on their websites. These look beyond carbon and account for multiple environmental impacts. Further, they provide a lifecycle assessment (LCA), and include both embodied carbon through end-of-life and operational carbon.

Experts can help

Many software tools exist to help conduct LCAs. One of the best free tools out there is the Embodied Carbon in Construction Calculator (EC3). This tool can technically be used by anyone, but it is most efficient if used between your architectural, engineering, and construction professionals along with a trained sustainability professional or firm. Increasingly, the emphasis shifts to embodied carbon as building codes call for increased energy efficiency, and more homes and utility grids are powered by renewable energy—thus significantly lowering the carbon footprint of operational carbon emissions.

By looking at these issues, weighing pros and cons, we can help reduce the embodied carbon and thereby the total lifecycle carbon in our homes. Particularly in new construction and all-electric homes, just a few adjustments in key areas—insulation, cladding, and concrete—can make strides toward meeting our collective climate change commitments and averting the worst of the climate change catastrophes to come.

 

The Author: Sustainability Consultant Arnaldo Perez-Negron is an environmentalist and social entrepreneur based in the Tampa Bay area.

 

Energy Efficient Homes Zero Carbon renovation.

Reference

Cold Climate Heat Pumps Warm Homes on the Coldest Days
CategoriesSustainable News Zero Energy Homes

Cold Climate Heat Pumps Warm Homes on the Coldest Days

By Zarkon Group,

In the US, about 13% of total CO2 emissions come from heating residential and commercial buildings. Because so many buildings rely on natural gas and heating oil, significant opportunity for reducing heating emissions lies with electric heat pumps. Heat pumps have been popular in the South for decades, but there are a lot of questions about how well they work in colder climates.

“A huge portion of our global emissions come from heating buildings,” says Brian Stewart, co-founder of Electrify Now, a volunteer organization devoted to electrification. “Since our homes are a big part of that, it’s important for us to understand the options we have for zero-carbon heating.”

Recently, researchers from the University of California, Davis did the math on switching from a gas furnace to an electric heat pump. Even with the mix of fuels that currently powers the electrical grid, a heat pump will produce far fewer emissions than a gas furnace, no matter where in the US you live. As the grid gets cleaner, the difference between electric and gas heating emissions will only continue to grow.

“We know that electrification works from a decarbonization standpoint, and we know that these heat pumps work in many situations,” says Stewart. “But we still have so many people wondering: Will heat pumps work in cold temperatures?”

Heat pumps, not just for warm climates

“With a standard heat pump, you start to lose efficiency as temperatures dip below 40°F,” explained Shawn LeMons, Performance Construction Manager for Mitsubishi Electric Trane HVAC US. “So, the system needs more electric power to extract heat from colder air.”

That’s where cold climate heat pumps come in.

Also known as high-efficiency heat pumps, these high-tech systems are specially designed to operate at a higher heating capacity in lower temperatures. “Cold climate heat pumps may look similar to standard heat pumps, but their internal technology and computer programming are far more advanced,” LeMons added. “They’re specifically built to function at subzero temperatures, all while operating as efficiently as possible.”

Location, location, location

Cold climate heat pumps are purpose-built for heating comfort and ease of use in inclement weather. You can use them in any “heating-dominated” region where HVAC systems spend most of the time heating instead of cooling. This includes climates with frequent snow and ice, as well as coastal climates with cold rain and fog. As long as your system is operating properly, it should be able to handle prolonged subzero temperatures, even at elevations thousands of feet above sea level, explained LeMons.

Households in milder temperature zones may also prefer a cold climate heat pump when the weather outside starts to get snowy or icy. You may not necessarily need a cold climate heat pump year-round, but having one will give you added benefits and comfort during the cold winter months.

Buying a cold climate heat pump

“Generally, because of the special features and programming, cold climate heat pumps can cost around 20% to 30% more than standard heat pumps,” said Jonathan Moscatello, Business Development Manager for Daikin North America. That’s because you’re paying for the system’s ability to pump heat in colder temperatures, and that’s where cold climate heat pumps shine.

“Compared to traditional heat pumps, they produce more heat per dollar spent, making them a better value in the long run,” said Moscatello. And that’s before you consider the potential tax incentives you’ll get when you make the switch!

Take note: Some manufacturers put all their premium technology into their cold climate models, so you’re also paying for features unrelated to the cold climate performance, Moscatello pointed out. So don’t be afraid to shop around for the best value.

What should you look for when picking out a cold climate heat pump? It depends on whom you ask. Start with the EnergyStar and Northeast Energy Efficiency Partnerships (NEEP) published standards for cold climate heat pumps. Most utility and government rebate programs also use these specifications.

“Manufacturers also have their own standards for what qualifies a heat pump for cold climate operation,” added Moscatello. “Examples of this include Mitsubishi’s Hyper-Heat line and Daikin’s Aurora line.”

Ratings and features to look for

LeMons and Moscatello recommend the following guidelines when shopping for a cold climate heat pump:

  1. Rated performance at 47°F.
  2. Maximum performance at 5°F.
  3. Capacity ratio at 5°F. This is the ratio of #1 and #2 above; the closer this number is to 100%, the better it can handle very low temperatures.
  4. Coefficient of performance at 5°F You want this number to be below 2. The lower the number, the better the system’s heat efficiency.
  5. Published performance at very cold temperatures, such as -13°F, -15°F, or -22°F. Keep in mind that these numbers give an idea of how the heat pump will perform on the coldest days. Many systems continue to work well at even lower temperatures.

Some typical features to look for:

  • Inverter compressors and advanced motors for greater energy efficiency
  • Advanced programming for cold climate operations, such as hot discharge air temperatures and “just right” airflow
  • Intelligent defrost cycles and drain pan de-icing
  • Optional wind baffles for an outdoor unit

At the end of the day, you’re buying a heating appliance, and you want to make sure it’s purpose-built for cold winter comfort. So, definitely read reviews and ask around before you buy!

Infographic showing advantages of heat pumps optimized for cold climates

The US Department of Energy’s Residential Cold Climate Heat Pump Technology Challenge is working with manufacturers to develop next-generation electric heat pumps.

Busting heat pump myths

Myth #1: You need a backup system to handle the coldest winter temperatures.

“Dual fuel is a legitimate path, but it’s not really necessary with a cold climate heat pump,” explained Stewart. Sure, standard heat pumps may need an alternate heating source like a furnace or boiler to take over when temperatures drop below freezing. Cold climate heat pumps, on the other hand, are equipped to handle the most frigid winters.

Laura Martel, Research and Evaluation Manager for Efficiency Maine offered an example of cold climate heat pump performance. “Caribou is a town in northeast Maine that’s IECC zone 7, the coldest climate zone in the United States. Homes in Caribou need their heaters for 6,444 of the 8,760 hours in a year.”

According to data from Efficiency Maine, it’s cheaper and more efficient to heat a home in Caribou with a cold climate heat pump than with a dual fuel system, natural gas, propane, or oil. While natural gas or propane systems may become more efficient when outdoor temperatures drop below 0°F, that only accounts for around 500 total hours each year in Caribou. Therefore, natural gas is more efficient than heat pumps only 5% of the time. For propane, that number drops to 1%.

“When you look at annual operating costs for various systems, heat pumps save people between $1,000 and $3,000 or more per year. Even if you switch to natural gas or propane for the small fraction of time that they’re cheaper, you’d only save an additional $26 per year, max,” said Martel. So, even though cold climate heat pumps may cost around $2,500 more to install than boiler systems, the yearly cost savings can quickly add up to make up for that initial expense.

Myth #2: Turning down the heat at night saves energy.

“We’ve been told for decades that we should turn down our home heater systems when we’re sleeping to save energy. That works great for boilers and furnaces, but I wouldn’t recommend it with heat pumps,” says Martel.

While furnaces can quickly blast heat into your home, heat pumps take longer to raise the temperature. When you turn your heat down at night, you reduce the rate of heat output of your system, temporarily lowering your energy usage. But when you turn it back up in the morning, your heat pump has to work extra hard to get the temperature back up. It doesn’t help that it’s usually colder in the early morning.

“Turning the heat down or off at night just isn’t as efficient as picking a comfortable temperature, setting it, and leaving it alone,” she said.

Still have questions?

If you’re interested in learning more about heat pumps, check out Electrify Now’s electrification fact sheet. You can also use this savings calculator from Rewiring America to estimate the tax incentives you’d receive from installing a heat pump in your home. Note that this article springs from Electrify Now’s cold climate heat pumps webinar, so check out their YouTube channel for more eco-friendly tips and technologies.

By Catherine Poslusny

Reference

Heat Pump Dryers: Low-Impact Laundry
CategoriesSustainable News Zero Energy Homes

Heat Pump Dryers: Low-Impact Laundry

By Zarkon Group,

If you’re interested in shaving off perhaps 10% of your household energy use (and your electric bill) with a single purchase, it’s time to look into heat pump dryers. “An electric dryer can use anywhere from 700 to 1000 kilowatt-hours of electricity each year. That’s about a tenth of the average American’s electricity usage,” said Joe Wachunas, electrification advocate for Electrify Now and Project Manager at New Buildings Institute. “You can cut that by 75% or more using heat pump dryers.”

With options on the market that use as little as 200 kWh of energy in a year, it’s not hard to see why their market share is increasing. “Heat pump technology is critical here in America, especially,” Wachunas says. “And heat pump dryers are an exciting, relatively new technology.”

Traditional vented dryers

Vented dryers can be either gas or electric, and they require venting to the outside of the home through ducts. A heating element heats the air in the drum, evaporating the moisture from clothes. Then as the dryer runs, the hot, moist air is vented outside and replaced with air pulled in from your laundry room, basement, or wherever it’s located. This influx of fresh air must be heated to continue drying the clothes.

Ga-Young Park,  Residential Appliances Manager at ENERGY STAR, pointed out another inefficiency. “Because vented dryers pull in cooled or heated air from your home and vent it outdoors, your air conditioner or heater has to work even harder to maintain the indoor temperature.” Also, vented dryer drums get very hot during operation, which—aside from the fire risk—can overdry clothes and potentially damage fabrics.

Heat pump dryers

Electric-powered heat pump dryers (aka ventless or condensation dryers) dry clothes without using a heating element or vent. Instead, heat pump technology pulls air into a condenser, heats it, and sends it into the drum, where it absorbs moisture from the wet clothes. Then, the air cycles to an evaporator, where it’s cooled. As the air gets colder, it loses moisture, which is either drained or collected in a removable tray.

That same air is then pulled from the evaporator into the condenser to be reheated while it’s still warm. In other words, heat pump dryers recycle warm air instead of venting it to the outdoors. Not having to heat fresh, cold air leads to big energy savings. Park added, “Heat pump models dry laundry at lower temperatures, which is much gentler on clothes. And unlike vented dryers, there’s basically no fire risk.”

Hybrid heat pump dryers

Hybrid heat pump dryers combine the heat pump cycle with the heating element of a vented dryer. This pairing helps the dryer drum get hotter, so clothes dry faster. Hybrid heat pump dryers are much more efficient than vented dryers, but because of the heating element, they’re less efficient than pure heat pump dryers.

Bosch heat pump dryer in butler's pantry setting; white tile and gray cabinets

Bosch WTG86403UC 300 Series 24 Inch Smart Electric Dryer, ventless. Images courtesy Amazon.

Size, price, and dry time

“People often think heat pump dryers take way longer to dry clothes because they use lower temperatures,” said Park. In reality, heat pump models can have dry times comparable to many vented dryers on the market today. All models with the ENERGY STAR label meet an 80 minute maximum dry time for a “typical” cycle, and some newer models demonstrate dry times as low as 50 to 35 minutes.

Historically, heat pump dryers have been compact in size, smaller than typical US household dyers. Things are changing, though. Park reported only ten options for standard-size dryers with heat pump technology, but expects that more standard-size heat pump dryers will continue to come on the market, particularly as hybrid models become more available.

Heat pump dryers are definitely more expensive than traditional vented dryers, but more and more, utility-sponsored rebates are available to offset the cost differential. Owners may also save on installation. Heat pump dryers do not require venting ductwork, which makes them simpler and less expensive to install. Homeowners can install the dryers nearly anywhere, provided the condensed water is allowed to collect or drain along with the washer.

Of course, you’ll also see major savings on your monthly energy bill.

Finally, the Inflation Reduction Act (IRA) will provide additional rebates and tax credits for homeowners looking to make energy-efficient home upgrades. (This savings calculator can help you estimate how much money you can save on a heat pump dryer through the IRA.)

Note: European households use an average of 3,700 kWh of electricity each year, just a third of what Americans use. Not coincidentally, while most of the world saves big money and energy by hanging clothes outside to dry, the practice is restricted or completely banned by many communities across the United States!

ENERGY STAR’s 6 Most Efficient Dryers

ENERGY STAR, run by the US Environmental Protection Agency, has overseen testing and labeling of quality, energy-efficient products for more than 30 years. The blue ENERGY STAR label signifies brands and models that are leaders in energy efficiency.

ENERGY STAR ranks dryers based on their Combined Energy Factor (CEF), a measure of energy efficiency. The higher a dryer’s CEF, the more energy efficient it is.

ENERGY STAR’s six most energy-efficient clothes dryers are all heat pump dryers (as of January 1, 2023).

Blomberg – DHP24404W 

  • Combined Energy Factor (CEF): 11.0
  • Estimated Annual Energy Use: 217 kWh/yr
  • Estimated Energy Test Cycle Time: 67 minutes
  • Additional Features: Sanitization cycle, Filter cleaning indicator, Steam cycle, Drum light, Time remaining display

Beko – HPD24414W 

  • Combined Energy Factor (CEF): 11.0
  • Estimated Annual Energy Use: 217 kWh/yr
  • Estimated Energy Test Cycle Time: 67 minutes
  • Additional Features: Sanitization cycle, Filter cleaning indicator, Steam cycle, Drum light, Time remaining display

Miele – PDR908 HP

  • Combined Energy Factor (CEF): 9.75
  • Estimated Annual Energy Use: 245 kWh/yr
  • Estimated Energy Test Cycle Time: 53 minutes
  • Additional features: Filter cleaning indicator, Drum light, Wrinkle prevention option, Time remaining display

Asko – T411HS.W.U

  • Combined Energy Factor (CEF): 9.1
  • Estimated Annual Energy Use: 263 kWh/yr
  • Estimated Energy Test Cycle Time: 80 minutes
  • Additional features: Filter cleaning indicator, Drum light, Wrinkle prevention option, Time remaining display

Samsung – DV53BB89**H*

  • Combined Energy Factor (CEF): 8.5
  • Estimated Annual Energy Use: 281 kWh/yr
  • Estimated Energy Test Cycle Time: 69 minutes
  • Additional features: Sanitation cyle, drum capacity 7.8 cu-ft

LG – WKHC202H*A 

  • Combined Energy Factor (CEF): 8.0
  • Estimated Annual Energy Use: 299 kWh/yr
  • Estimated Energy Test Cycle Time: 72 minutes
  • Additional features: Wrinkle prevention option, time remaining display, drum capacity 7.2 cu-ft

This article springs from Electrify Now’s webinar on Heat Pump Dryers. For more strategies and technologies to electrify your home, visit their YouTube Channel.

By Catherine Polslusny

Reference

7 Simple Steps to Decarbonize Your Home
CategoriesSustainable News Zero Energy Homes

7 Simple Steps to Decarbonize Your Home

By Zarkon Group,

By Peter Dull

With carbon emissions reaching an all-time high, it is important to discuss how we, as a global community, can minimize the carbon load of our buildings. As of March 29th of 2019, we surpassed over 410 ppm (parts per million) of carbon dioxide (CO2) in our atmosphere. To put this into perspective, our sea levels have risen between 0.1 to 0.13 inches per year; and our global temperature rises 2 to 3 degrees Celsius yearly because of carbon emissions. These astronomical figures are the necessary wake-up calls we need in order to help meet the goals of the Paris Agreement*.

*The Paris Agreement is a worldwide initiative that calls for action on the threat of climate change. The agreement consists of two parts: decrease the global temperature by 1.5 degrees Celsius yearly and increase access for countries that require resources (i.e. technology and finance).

What is Decarbonization?

Decarbonizing our homes is one of many ways we can be more conscious of our current lifestyles. Decarbonization refers to the removal of carbon from the environment. In the case of housing, homeowners can reduce energy use and reliance on fossil fuels (i.e. gas furnaces), and choose building materials that require either low amounts of carbon emissions to manufacture and transport, or actively sequestrate carbon by storing carbon that is drawn from the atmosphere. We will address why you should consider your energy and material uses, and how you can develop a carbon-neutral home.

How Can You Decarbonize Your Home?Graphic show three strategies to decarbonize your home

 

Energy Efficiency

When considering how to decarbonize your living space, first think of this in terms of the amount of energy (and carbon) being used. You can reduce your carbon load by losing less energy to leakage, making use of passive heating and cooling, and upgrading the efficiency of your appliances.

Insulate and Eliminate Air Leaks

As Katrin Klingenberg, Co-Founder and Executive Director of Passive House Institute US, says “The greenest energy is the energy we don’t use at all.” A well insulated house which is extremely airtight has an oversized impact on the heating and cooling needs and therefore reduces carbon emissions. If you go for a Passive House standard, you can see overall energy savings as much as 90% on space heating. Innovative new products such as Havelock wool insulation and Aerobarrier have envelope sealing technology that make this easier and more cost effective than ever before.

High-Performance Windows & Doors 

You may ask yourself “aren’t all windows and doors created the same?” While this may sound realistic, there are advantages when you invest time researching these products. Not only can you allow natural ventilation in your home, you also can have a virtually airtight seal when closed.

Natural Lighting and Passive Solar

Using skylights and repositioning your windows at home are some savvy ways to change-up your home. Skylights and windows reduce the need for artificial lighting and rely on more beneficial, natural lighting to lighten up the aesthetics in your home. By repositioning your windows to face southward, your home can be protected with overhangs to protect against the high summer sun and be aligned with the recently-trending design of Passive solar. If you are looking to buy supplies that reduce your sunlight intake, buy some awnings and window shutters to make that possible.

Efficient Lighting and Appliances

Your electric load can be greatly reduced by using LED lighting in your home.

Always look for Energy Star appliances that are certified to use less energy to get the job done.

Intelligence Controlled

As a quick reminder, always remember that when you are not using something, turn it off or close it off! As simple as it sounds, many homeowners seem to forget, resulting in a utility bill higher than their expected value.

Now that we are immersed in the “digital age,” it is easier than ever to control your home through your smartphone and/or virtual home assistants. This type of intelligence can save you money as you can monitor and control your usage from virtually anywhere to reduce energy use. Some innovative products include airtouch and switchmate.

Renewable Energy

Currently, the average American household produces 7.5 tons of carbon dioxide per year. By switching to renewable power sources, homeowners not only save money on their utility bills, but can reduce their carbon footprint. Keeping additional carbon out of the atmosphere takes us closer to meeting goals that correlate to sustainable living.

What does it mean to have “cleaner energy” on the grid?

Expanding your grid is like adding colors to a painter’s palette. As you discover new ways to diversify your power sources, you have more options to work with and it can be easier to construct a house through a variety of styles and sources. By incorporating appliances and innovations that rely on and produce renewable energy, you decrease your carbon output and help reduce the amount of “bad energy” that’s being utilized. In addition, you can install battery storage that helps bridge the gap between times of excess energy generation during the day and times of lower renewable production.

Solar

The most well-known renewable energy solution homeowners are investing in is solar energy. Solar panels, either placed on their roofs and/or walls, are helpful for homeowners in locations where the sun is apparent throughout the year. Solar photovoltaics (or PV for short) increase your grid security and are a very economical source of energy.

The SunPower Equinox system, for example, offers innovation at every level, from its Maxeon solar cell technology to each panel’s individual microinverter to the SunPower SunVault battery. The latter allows the solar panels to remain powered for longer even in times of power outages and shade.

Wind

As much as the term “wind turbine” sounds daunting, there is nothing to be scared of! If you have a large plot of unused land, consider installing a small turbine. These windmill-like structures generate energy through the rotation of their propellers and then transfer that energy to an electricity grid for use. With an average payback of fewer than 13 years (machines last 20+ years), this is a smart investment in the long-run.

Geothermal

Geothermal energy can be an option to provide heating, cooling, and hot water for the home. Although there might not be any volcanoes near your home, modern heat pump technology becomes handy when warming your living space. These systems take advantage of the relatively constant temperatures below ground to transfer heat and apply cooling properties where they are needed. Even though this system may be costly up front, they are a great carbon-neutral option for your home’s operation – even Alphabet is getting in on the action with their spin out Dandelion.

bright metal pot (double with lid) on flat black industion cooktop surrounded by white couterntop and walls of kitchen

Going All-Electric

As your home’s grid takes in more renewable sources, it makes sense for homeowners to switch to all-electric appliances and systems. Modern high-efficiency electric systems such as heat pump water heaters and induction cooktops are more effective and efficient than their gas counterparts – it is all win and no loss. Now that you can cook with an upgraded system, your stoves reduce the output of CO2 to zero and you and your family can keep warm without the worries of fossil fuel. As a bonus, you can also invest in transportation that is dependent on electricity, like hybrid cars and your local train system.

Materials

So far, we have been discussion “operational carbon”. The carbon emissions that are generated in order to run your home.

You should also consider “embodied carbon”. This is the carbon that was used to create, extract, fabricate, and transport the materials to your site.

When selecting materials for your build or renovation, you can ask yourself some basic questions:

  • Is this manufactured and transported in a low carbon manner?
  • Does this store (sequester) carbon in my home by using materials which pulled carbon out of the air?

If any of your answers are yes, then congrats – you are on your way to decarbonizing your home. When you consult with a local construction firm, keep in mind not only the structure of your ideal home, but how different sustainable materials can save you energy and money. You can explore certifications such as the LEED or the Living Building Challenge. You can find information on your product choices through online resources such as the Carbon Smart Materials Palette.

Low-Embodied Carbon Materials

CO2 emissions, which are used to manufacture and transport a material, are referred to as the ’embodied carbon’ of that product. Between 2020 and 2050, it is expected that embodied carbon will be responsible for almost half of total new construction emissions. So how can we work as homeowners to reduce carbon in our materials? Just keep on scrolling down!

Renovate and Reuse

When undertaking a new project, it is almost always more carbon efficient to renovate instead of demolishing and building anew. If you are taking out an existing structure, look for opportunities to donate and reuse building materials instead of sending them to a landfill. By using reclaimed materials for your project, this will result in a net-zero carbon product and will take less labor to start something new.

Avoid Carbon Intensive Materials

With the continued push towards transparency, it is becoming easier to understand the carbon footprint of materials. Databases such as the Inventory of Carbon and Energy provide critical insights that allow homeowners to better comprehend what they are installing for their home. Some carbon-intensive materials (i.e. concrete) can be produced using materials which are waste (such as fly-ash) and other materials (i.e. cork) that are naturally low-carbon or even no-net-carbon.

Consider Materials that Sequester Carbon

If your project uses materials that pull carbon out of the air, aka materials that are natural and undergo photosynthesis, then those materials can be said to sequester carbon in your home. When constructing your home, it is important to consider the longevity of your building and how carbon can be drawn from the air and be safely stored in your home. By supporting sustainable forestry practices in your choices, you will contribute to carbon drawdown and the overall green movement.

New products such as cross-laminated timber (CLT) allow wood to replace steel and concrete for many structural applications.

For your consideration

Thanks to programs such as the Technology and Equipment for Clean Heating (TECH) and Building Initiative for Low Emissions Development (BUILD), which are both found in California, sustainable living can be a reality for homeowners. These complementary, statewide initiatives facilitate easier access to water and heating equipment at a lower cost and require residential and commercial buildings to cut their carbon emissions by 2040.

Search online to see if your state has tax incentives and rebates to make your greener housing dreams possible.

See how easy this was? Watch as your home becomes more energy efficient by incorporating practices of renewable energy from your own system or the grid. Just as a reminder, you should select products and materials that were created via efficient use of carbon and consider opportunities that store atmospheric carbon with materials within your home. Good luck and happy building!

Reference