Act Now: List or Update Your Home in the Inventory of Zero Homes
CategoriesSustainable News Zero Energy Homes

Act Now: List or Update Your Home in the Inventory of Zero Homes

Did you know that as of the end of 2020, there were more than 17,000 zero energy housing units in North America? That’s a 26% increase over the previous year. Many more are in the pipeline for 2021. Other interesting facts: 75% of zero energy residences in North America are multifamily, and London, Ontario, Canada has more zero energy residences than any city in North America. This is the kind of information you can access from Team Zero’s Inventory of Zero Energy Homes

The Inventory of Zero Energy Homes provides a crucial metric to demonstrate the growth and viability of the zero energy movement. If you have designed, built, or purchased a zero energy home, be sure it is listed in the Inventory.  Because there are now new inventory data fields where you can provide more useful information on your home, if you already listed a home, please update your listing. You can add or update your listing here.

But act fast. Team Zero, EEBA, and the Zero Energy Project encourage builders, designers, and homeowners to submit new zero energy homes and update previously listed ones soon — so they’ll appear in the 2021 Inventory of Zero Homes report. 

The Inventory covers many categories: homes currently under construction, those in the design phase, and completed homes — whether they’re zero energy, positive energy/net producer homes, zero energy ready or passive homes. The 2021 Zero Home Inventory report will help build momentum for zero homes. Stand up and be counted by listing or updating your zero home in the Inventory now!

 

Reference

Go Small, Live Well – Zero Energy Project
CategoriesSustainable News Zero Energy Homes

Go Small, Live Well – Zero Energy Project

Hopefully, this period of human existence will be known for the rapid and effective response to the existential crisis of climate change. Either that, or human culture will descend into a Mad Max scramble for survival. Either way, homes will be changing. Perhaps the most noticeable change will be the shrinking of living space. The median square footage of a new home sold in the US in 2020 was 2,333 square feet, and many “luxury” homes range from over-sized to gargantuan. Fortunately, there is a counter trend of modest-sized houses that are more affordable and fit better on small urban lots. And that counter trend has deep roots. In the late 1940s, the average new home was just 750 square feet. In the 1950s, it increased to 950 square feet, 1,100 square feet in the 1960s and 1,350 sf in the 1970s. In fact, most of us at an age to purchase a home were raised in houses that are much smaller than those we see on the market today. 

 

Small homes have smaller carbon footprints. They consume fewer building materials, need smaller equipment, cost less, and require less energy to operate. Even better, they require less time and effort for cleaning and maintenance. You may think that less living space means sacrifice, but a well-designed home can live big in fewer square feet. 

 

The right size home is the smallest that will work for your current needs. Many homebuyers fall into the trap of buying for “resale.” They buy rooms and features that they don’t really want or need, because they may believe the market demands these features. If it was ever true, it’s now a myth perpetuated by some real estate brokers. There’s a need to educate today’s homebuyers to see through the myth that “bigger is better.” In fact, as the housing market changes, it’s likely that large homes with empty bedrooms and high energy bills may not compete well in the market as smart buyers migrate to small, energy-efficient homes with lower operating costs. And today’s homebuyers will want to be in the vanguard of this trend, not the tail end. 

 

Everyone is different and has different needs, but here are some basic size considerations: 

  • Single person or couple: 600-1,000 sq. ft.
  • 3 to 4 person family: 1,200 – 1,600 sq. ft. 
  • Larger families 1,800 to 2,000 sq. ft. 

 

Good design can deliver comfort, utility, and a feeling of spaciousness in a smaller space. The deciding factor should be that homes fit the owner’s current needs and known needs for the future in the smallest possible footprint. 

 

Follow the principles of smart, small home design 

 

Keep it simple. Architectural complexity increases cost and complicates insulation and air sealing details. This doesn’t mean that we need to live in cubes. However, when you add corners beyond the usual four, make sure the benefit outweighs the costs. Think of the home’s footprint as two or more connected rectangles — small ones. 

Invite natural light. Careful selection, sizing, and location of windows can flood a small space with natural light, making it look larger without increasing energy use. Windows with higher sill heights limit total window area while preserving views, and light — providing ample space to place furniture against the wall below the windows. 

Share light between rooms. Indoor windows, glass block partition walls, full- or half-lite glazed doors, and transoms allow light from a brighter space into an adjacent area that has less natural light. Operable transoms also allow better air circulation in small homes that use ductless heating and cooling systems. 

Open floor plans. Most modern layouts connect cooking, eating, and living spaces in a more open pattern. This makes each individual space feel larger and allows for long interior views and good air circulation. 

High ceilings. Smaller rooms need not feel cramped. High ceilings (nine or ten feet) add an airy feeling and visual interest. Consider well insulated cathedral ceilings, which create more interior volume. Some of this volume can contain usable space, such as lofts, mechanical rooms, or heated storage. Even if it’s not directly functional, high ceilings bring visual appeal to smaller rooms. 

Reduce circulation paths. Shorten or eliminate hallways, unless they serve a dual purpose. Traffic patterns can flow around the perimeter of rooms with open floor plans adding to the perception of spaciousness.

Eliminate formal spaces. Formal living and dining rooms are seldom used. Most people gather in kitchens, family rooms, or outdoor spaces. Avoid showcase rooms that are rarely used.

Create soft separations. Distinguish between functional spaces without building walls. Divide large rooms with “soft” visual cues, such as differing floor finishes, wall colors, moveable partitions, hanging plants, or furniture arrangements that differentiate the spaces. Or you can tie spaces together visually using similar materials, such as flooring, wall coverings, and trim, giving the overall impression of greater space.

Multi-use spaces. Every space in the home should serve more than one function. A home office and guest bedroom is a common combination. A hall or stairway can be used as a library or gallery, a landing can be a reading nook, the mudroom or bathroom can be a laundry. Install built-ins for exercise equipment and media, rather than using separate rooms — or include an exercise nook in the garage.

Build in furniture. Cabinets, bookcases, benches, work desks, and eating nooks use less space when they become part of the structure. Recess bookcases or display cases into interior walls. 

Create privacy. Everyone needs a place to spend a bit of quality time alone. This can be difficult in a small house, so create a private space. It could be a cozy window seat, a secluded loft, or a comfy chair in a solitary corner. 

Laundry in a closet. The washer and dryer don’t need privacy. Instead of getting their own room, stack them in a closet or in other space, such as a mudroom, bathroom, or utility closet. Several utilitarian functions, such as laundry, water heating, and ventilation equipment can be located in a mudroom. Add shelves and cupboards for cleaning supplies and linens, and space for hanging clothes to dry. 

Contain the mess. Clutter makes spaces seem smaller. There are countless methods to stay organized. Give the kids their own built-in cubbies in the mudroom to store coats, hats, and other personal gear. Add shelves and cupboards above a mudroom laundry. Add closets under stairs.

Include unheated space. Storage, hobbies, and exercise can tolerate a wide range of temperatures. Expand unconditioned spaces, such as the garage, full basements, or sheds to accommodate these functions at much lower cost per square foot. 

Encourage outside living. Large patios and decks extend the living space during mild weather. 

Bring in the outdoors. Locate windows and glazed doors for optimal views of the outdoors to create a visual extension and bring the outside in. Patio, deck, or courtyard doors extend the living space past the outer walls during fair weather. 

Work-at-home space. Remote workers cherish a quiet place to concentrate. Combine a home office with a complimentary function. A bedroom can be used at night for sleeping and during the day for office work — and these functions can be kept distinct. A Murphy bed will hide away during the day, and desk and work tools can be concealed by a cabinet or a curtain when not in use. 

Provide ample storage. When people want a “bigger house” they may actually need more storage. In small homes, careful planning can provide densely packed, three-dimensional, tightly organized storage — so it does not add square feet. Instead of large walk-in closets and pantries, consider making them open spaces where you can easily access three walls of shelves. If you have a closet door, you can use the back side of the door for hooks, racks, or baskets. Make use of the stairwell walls for hooks or cupboards. Always use the space below a staircase, but be more sophisticated than a simple closet door leading into an oddly shaped room. The shorter regions near the base of the stairs could have large drawers that fully use the space below the bottom steps. 

Stop swinging. Sliding doors use less space than swinging doors. Consider using pocket doors that slide into a wall cavity, a rolling door that hangs on the wall surface, a simple curtain on a rod, or no door at all. Rolling doors don’t seal tightly, which could be a concern for privacy. On the other hand, there is ample airflow around the door for ventilation and space conditioning to penetrate. 

Plan for flexibility. The design should allow for changes in lifestyle. A young couple may have children. Grown children will leave the nest. A business could be born in the kitchen and grow in the guest bedroom. Plan for these changes. Pre-plan a future addition or consider ways new uses could be accommodated inside the existing footprint. The upstairs or basement could become an apartment for an aging relative. 

 

Stock Plans for Small Homes

We may think that building small homes is a new idea, but in the 1950s through the early 1970s the Canada Mortgage and Housing Corporation released a series of small house designs to encourage affordable housing. The concept behind these plans holds up well today, but it needs to be updated to zero energy and contemporary expectations, such as multiple bathrooms. 

 

Some modern designers are also embracing the idea. Here’s a contemporary take on small house plans that can be upgraded with energy-saving features. Zero Energy Plans offers plans for a range of small zero energy homes. Just click on “Plan Filters” and go to the zero energy home size choices to find a suitable match. 

 

If you can’t find the perfect house plan, consider a custom zero energy design that meets your size needs exactly. Seek out zero energy designers and builders who understand the trend towards smaller more energy-efficient homes. With good design and conscientious construction, you may find that a small, custom-built, zero energy house is not only within reach but lives very well! 

Reference

The 2021 EEBA Team Zero Inventory of Zero Energy Homes Is Now Underway
CategoriesSustainable News Zero Energy Homes

The 2021 EEBA Team Zero Inventory of Zero Energy Homes Is Now Underway

MINNEAPOLIS, December 2, 2021 (Newswire.com) – The Energy & Environmental Building Alliance (EEBA) is embarking on the 6th annual EEBA Team Zero Inventory of Zero Energy Homes and invites all zero energy (ZE) builders, designers, architects, developers and owners to upload their projects to the database.

The yearly report tracks ZE single and multifamily home trends and leaders across the U.S. and Canada. Currently, the Inventory includes ~28,000 ZE projects voluntarily submitted.

As of the 2020 report, all projects are zero-energy ready and above, with the minority of projects listed in the Inventory as net zero or net producers. “The reality is that many homes, although they may not achieve that absolute goal, are designed as part of the larger movement towards zero energy, and we can learn from all of them. So, we included all of them,” the report explains.

“Maintaining the Inventory is important because it sheds light on North American ZE growth patterns, high-performance technologies used, as well as the major players who are adopting ZE design and construction as a profitable business model,” EEBA’s CEO, Aaron Smith, says.

The need for ZE housing is clear. According to the U.S. Department of Energy, U.S. homes consume ~ 21% of the total energy used annually. As for carbon emissions, the average home releases 70% more CO2 into the environment than a typical car or about 17,320 lbs. yearly. Thus, reducing home energy demand to net zero is economically and environmentally critical as well as achievable.

EEBA Team Zero started tracking the proliferation of U.S. and Canadian ZE homes in 2015. Since then, the yearly report has shown a consistent upward trend, with the multifamily sector leading the pack. “Multiunit developers don’t adopt practices that aren’t profitable,” concluded Smith.

Those interested in submitting their projects to the Inventory can go to https://teamzero.org/add-your-listing/. Projects approved before Feb. 15, 2022, will be added to the 2021 report. For questions regarding the Inventory or other media inquiries, please contact mary@eeba.org.

 

About EEBA Team Zero

For over 35 years, EEBA has provided the most trusted resources for building science information and education in the construction industry. EEBA delivers turn-key educational resources and events designed to transform residential construction practices through high-performance design, marketing, materials, and technologies. In addition, EEBA reaches thousands of key decision-makers and other essential industry players each year through our educational events, the annual Summit, and various publications and resources. In 2021, the nonprofit Team Zero integrated their services and expertise into EEBA’s organization. This integration includes “The Gateway to Zero” and The Inventory of Zero Energy Homes Database and related reports. To learn more about EEBA Team Zero, visit www.eeba.org.

Reference

Low-Cost, High-Value Opportunities to Reduce Embodied Carbon in Buildings
CategoriesSustainable News Zero Energy Homes

Low-Cost, High-Value Opportunities to Reduce Embodied Carbon in Buildings

Buildings account for at least 39% of energy-related global carbon emissions on an annual basis. At least one-quarter of these emissions result from embodied carbon, or the carbon emissions associated with building materials and construction. The solutions for addressing embodied carbon in buildings have not been widely studied in the United States, leaving a significant knowledge gap for engineers, architects, contractors, policymakers, and building owners. Further, there is little information about the cost-effectiveness of reducing embodied carbon in buildings.

RMI’s new report, Reducing Embodied Carbon in Buildings: Low-Cost, High-Value Opportunities, helps fill this knowledge gap. The report demonstrates low- or no-cost options to reduce embodied carbon in buildings and provides design and construction strategies that can help limit a project’s embodied carbon. The case studies showcased in the report show an embodied carbon savings potential of 19% to 46% at cost premiums of less than 1%. Current practice indicates that we can achieve these reductions by specifying and substituting material alternatives with lower embodied carbon during the design and specification process. Far greater reductions are possible through a whole-building design approach.

This report was developed to help building owners, designers, contractors, and policymakers understand the low-cost and no-cost solutions for reducing embodied carbon in buildings. To accomplish that, we studied three building types and considered design strategies that can reduce embodied carbon at any stage of a project’s design and construction phases. The report quantifies the construction cost difference associated with low-embodied-carbon solutions and points to next-generation solutions that could drive even greater reductions.

 

Top categories of building materials for reducing embodied carbon.

 

Critical Materials Driving Embodied Carbon in US Buildings

In order to tackle embodied carbon in buildings, we first need to understand the carbon impact of the industries driving embodied carbon emissions. A building’s structure and substructure typically constitute the largest source of its up-front embodied carbon, up to 80% depending on building type. However, because of the relatively rapid renovation cycle of building interiors associated with tenancy and turnover, the total embodied carbon associated with interiors can account for a similar amount of emissions over the lifetime of a building. Our report focuses primarily on structural materials, metals (including steel and aluminum), cement, and timber. Each of these materials has a different embodied carbon content but is critical to our consideration of structural systems in this context.

 

Proven Solutions and Strategies to Reduce Embodied Carbon

Today, there are many solutions that can be leveraged to limit embodied carbon in new buildings. The totality of low-embodied-carbon solutions includes a long list of offerings that span a wide range of complexity.

Most simply, low-embodied-carbon solutions for buildings can be broken down into three main categories: whole-building design, one-for-one material substitution, and specification. In general, whole-building design solutions can drive the greatest embodied carbon savings. However, material substitution and specification can also result in substantial embodied carbon savings, especially when these solutions target carbon-intensive materials such as concrete and steel. Furthermore, these categories are not mutually exclusive — they can be combined or performed in parallel to drive deeper embodied carbon savings.

The following graphic demonstrates embodied carbon best practices that can be implemented throughout the building design and construction process.

Case Studies in the Economics of Low-Embodied-Carbon Buildings

One core objective of the report is to answer the question: How much can we reduce embodied carbon in new buildings at no additional cost?

In short, this study shows that embodied carbon can be reduced by 19% to 46% in mid-rise commercial office, multifamily, and tilt-up-style buildings by leveraging low- and no-cost measures. Together, these measures increased overall project costs by less than 1%, which is within the margin of error for most construction project budgets.

 

Skanska, one of the world’s leading sustainable construction firms, provided cost data from three actual projects in the Pacific Northwest and conducted an analysis under the guidance of RMI to generate the results of this study.

These case studies lead us to a few powerful observations. Even though the strategies employed do not include comprehensive, whole-building design strategies, they still yielded reductions of up to 46% in up-front embodied carbon through specification and material substitution measures. Given that these conclusions are based on three case studies in the Pacific Northwest, we can note them as strong anecdotal evidence, rather than broadly applicable conclusions.

Given the fact that we were not able to redesign building structural systems, we were unable to draw deep conclusions about the cost, carbon, and material impacts of whole-building design solutions, such as substituting more structural steel and concrete with wood. Given this scope, our key findings are:

  1. Optimizing the ready-mix concrete design can lead to significant embodied carbon reductions (14% to 33%) at no cost, or with a possible cost reduction in some cases.
  2. Rebar contributed up to 10% of total project embodied carbon in two case study buildings, but rebar’s up-front embodied carbon can be cut in half with minimal cost impact to the overall projects. These results may vary by location, as rebar with high recycled material content may not be available at a low cost premium in other regions.
  3. Insulation material selection can be a significant factor in project-level embodied carbon, with insulation making up approximately 20% of one building’s baseline embodied carbon content. Insulation products utilizing hydrofluoroolefin (HFO) or other foaming agents with low global warming potential can reduce embodied carbon impacts significantly, and several emerging plant-based products have the potential to store more carbon than is emitted in their production.
  4. Glazing remains a critical challenge for reducing embodied carbon, between the significant amount of heat required for glass production and the high-embodied-carbon materials often used for framing. Products available today can cut embodied carbon in glazing by approximately 25%, but at a 10% cost premium.
  5. For some finish materials such as flooring, carpet tiles, ceiling tiles, and paint, embodied carbon reductions of more than 50% are possible at no up-front cost premium. In some locales, carbon-sequestering materials may even be available.

 

Read the Report to Learn More

The Reducing Embodied Carbon in Buildings report includes detailed information about each of the three building case studies, sections exploring related topics such as tenant fit-outs and building reuse, and further analysis of our key conclusions. Download the report to learn more about opportunities for reducing embodied carbon in buildings, and why embodied carbon needs to be addressed now to drive the most impact.

 

Matt Jungclaus is Manager of Carbon Free Buildings at the Rocky Mountain Institute

Reference

Interior Design Ideas for Living Big in Small Spaces
CategoriesSustainable News Zero Energy Homes

Interior Design Ideas for Living Big in Small Spaces

While some large-scale builders still cling to huge home floor plans and many upscale buyers still demand them, there is a rapidly growing interest in smaller homes. Small homes use less energy, require a lower carbon input, and cost less to maintain than the typical suburban estate. If you’re building a new home, you have many options for reducing size and living very comfortably (link to Part I). If you’re buying or living in an existing small home, you also have opportunities to make it live bigger without ripping into walls or raising the roof. It’s amazing how creative interior design can expand the visual space and increase the comfort and utility of a small home. Here are some tips.

 

Interior Design

Keep it light. Paint the walls a light color. Various shades of white or beige are classic choices. If you’re more adventurous, consider light yellow or pastels. Accent walls of brighter hues can add interest. To make a room seem brighter, select an eggshell finish that is slightly more reflective than flat wall paint. Use semi-gloss paint in bathrooms to reflect light and reduce vapor diffusion into walls. 

Choose flooring material. Using the same flooring material for connected spaces will tie the spaces together visually and make them look larger. For example, a kitchen and dining area could have the same tile flooring. Using different materials, distinguishes spaces without actually interrupting the view. A living room next to the dining area can be defined with a hardwood floor, but not blocked off. 

Install mirrors. Reflecting light and extending interior views can be accomplished with strategically placed mirrors

Occupy window sills. Most zero energy homes have thick walls, which brings the added benefit of wide window sills. Consider enhancing their interest with bold sill material, such as stone, tile, or another unique finish. Make the most of these built-in shelves to grow houseplants or display decorative items. 

Enhance trim and detail. High-quality trim and detail can be a key focus of a small house. For example, high-quality hardware and moulding, and other aesthetic touches, can draw attention to the details creating more visual interest with less need to clutter the room with knick-knacks.

Add a focal point. Each room should have one attractive attention-getting feature. This can be a building element, such as built-in furniture, a work of art, or an intriguing light fixture.

 

Furnishings

Choose quality. Too much clutter makes homes seem small. Small homes should have small comfortable furniture or a smaller amount of carefully selected larger furniture. 

Open up. Select chairs and sofas with open legs instead of those with enclosed bases. These pieces seem lighter and offer a bit more visual space in the room because you can see below them. 

Include storage. Some furniture pieces come with storage, such as an ottoman or footstool, that opens up and contains storage. Some bed frames come with storage below the mattress, either in drawers or the mattress itself may lift. 

Make it tall. Well-designed small homes have high ceilings. Much like clothes with vertical stripes make people look taller, tall furniture pieces will accentuate tall ceilings and draw the eye upward. Similarly, a tall plant will reach into the higher spaces and create visual interest.   

Fold it. Find furniture that transforms to different uses. A coffee table can become a dining table. Tables that hinge down from the wall will allow them to be deployed without moving objects sitting on the floor. The classic space-saving transformer is the Murphy bed. This allows the bedroom to have a day job, too. 

Hidden offices. There are many “hidden” desk ideas that allow for a home office to be discreetly hidden or camouflaged in a living area or bedroom.

Seek niche storage. Look for the small empty spaces that can hold your stuff and reduce clutter. Cabinets can hide less attractive household items, while open shelves can display your treasures. Examine the back side of the closet and pantry doors. Is there space for wall-mounted storage baskets or hooks that will be out of site, but easily accessible? 

 

Few small homes will use all these ideas, but each one has its merits. Apply the ones that make sense for your situation to make your small home look and live bigger. Be proud that your small home reduces your carbon footprint, has less upkeep, and saves you money without sacrificing comfort.

Reference

Net-Zero vs Passive House: What are the Similarities and Differences?
CategoriesSustainable News Zero Energy Homes

Net-Zero vs Passive House: What are the Similarities and Differences?

Have you ever wondered what the difference is between a net-zero house and a passive house? They’re both buzzwords in the green industry. But also appear in the mainstream news and the speeches of politicians. Gaining in popularity, it’s good to be aware of the differences. In some cases, it’s the smallest of details. But these different approaches to building can have a big effect on cost, comfort, true sustainability, environmental savings, and much more. We’ll explain the differences so that you can make an informed decision on which type of green building to pursue when designing or renovating your own home. We’ll also share how our family approached our first net-zero solar home renovation project, and how we kept costs to a minimum.

What is a Net-Zero Energy Home?

A net-zero home produces as much energy on an annual basis as it consumes. Design and engineering usually involve off-the-shelf energy-efficient technology and renewable energy sources, such as solar panels, to reach zero net energy use throughout the year. It may not necessarily be completely engineered to use the lowest energy possible, but if it produces enough to make up for those shortcomings, it could be considered net-zero.

 

An overhead drone shot of our first net-zero home in Cape Coral, Florida. It shows a newly renovation white 1,836 sq ft home with a big solar system on the roof.Our own affordable net-zero home renovation project in Cape Coral, FL.

(See more at Our First Net-Zero Solar Home Renovation (And How We Did It) – Attainable Home)

What Is a Passive House?

You’ll find many definitions on the web. But most agree that a passive house has highly engineered energy efficiency and stringent design standards while using environmental factors, such as passive solar, to keep energy use as low as possible. It’s a voluntary standard to achieve comfort, affordability and the lowest ongoing environmental impact possible. Here’s how the Passive House Institute defines a passive house: “Passive building comprises a set of design principles used to attain a quantifiable and rigorous level of energy efficiency within a specific quantifiable comfort level.”  Another way to describe it is that it “optimizes gains and losses” based on climate. You can learn more at Passive House U.S.

What Similarities Do These Homes Share?

The good news is both are extremely more energy-efficient and sustainable than an average house. And it doesn’t even have to cost that much more either.

Passive houses and net-zero homes share much in common. Both types of homes aim to make sure that their energy consumption is as close to zero as possible. 

There are many differences in how they accomplish this, but for the most part, both passive and net-zero houses follow similar principles. 

Common Characteristics of Both Net-Zero and Passive Homes:

None of these are requirements, but all energy-efficient homes, regardless of the label, usually aim to have most or all of these characteristics:

  • The building envelope is as air-tight as possible within budget. If you can control the air inside and prevent air leakage, the mechanical systems run less.
  • Elimination of thermal bridging when possible. A thermal bridge is a component in the house that acts as a thermal conductor between the inside and outside of the house, such as window and door frames.
  • High-performance energy-efficient windows.
  • Thick and continuous insulation through the entire building envelope. Insulation acts like a blanket around your house (similar to your to-go coffee mug that keeps your coffee warm for longer).
  • Mechanical ventilation that keeps air healthy and fresh. Because your building envelope is so tight, the air inside your home has nowhere to go. You must move that stale indoor out and bring fresh air in from the outside while retaining the heat using an energy recovery ventilation system.
  • Efficient mechanical systems and appliances. Things like HVAC, your hot water heater, washer, dryer, refrigerator, stove, dishwasher, and others must be energy efficient. But perhaps more importantly – they must be designed correctly for the home. If systems are too big or small for their actual workload, they can work overtime and burn out.
  • Some use of shading. Ideally, you have shading on the roof that is optimized to let the warm sun in through the winter (when the sun is lower in the sky) and shade for the windows in the summertime.
  • Renewable energy. Even with energy-efficiency measures and stringent passive house standards, you may still need to generate some power to get to net-zero. This is where solar energy, small wind turbines, geothermal, or perhaps small micro hydropower might come in. We did a whole article on solar alternatives if you’re interested in learning more about that.

The major difference between passive and net-zero homes is that Passive House’s stringent standards for insulation, air sealing, and use of passive solar reduce the energy needs of the building to the point that very little solar may be needed to get to net zero. On the other hand, net-zero homes have less stringent standards and may require more solar to get to zero.

How Much Do These Energy Efficient Homes Cost?

Many factors contribute to the total cost, so it’s hard to say exactly. The best graph we’ve found appears in  Rocky Mountain Institute’s 2019 report, “The Economics of Zero-Energy Homes,” which shows that net-zero homes only cost about 6-8% more than traditional homes.*

Courtesy of the Rocky Mountain Institute study entitled The Economics of Zero-Energy Homes

Similarly, according to the Passive House Institute US, a passive house typically costs 5-10% more than a typical home. For the net-zero home renovation we did (see below), the efficiency measures and solar energy costs equate to 6.8% of the final appraised home value, so nearly dead-on with RMI’s findings.

A Case Study – Our Attempt at a Net-Zero Home Renovation

I wanted to create the most affordable net-zero home renovation I could muster. The goals were clear and deliberate:

  1. Keep the total cost under the median average home price of the area.
  2. Ensure that it could rent for 10-15% above all ownership costs, including long-term maintenance. This is because things change in life and I wouldn’t  be forced to sell in a down-market.

I was aware of the Passive House concept before starting, but my goal was to get to net-zero as affordably as possible. The reality is, unless you’re building from the ground up, a Passive House design is difficult to implement because most existing homes would require extensive renovation to meet Passive House standards.

My approach was to use energy and financial models to go after the lowest hanging fruit. This created the freedom to let the spreadsheets tell me what to do on the project. This is house-specific, so each project is different.

Going After The Lowest Hanging Fruit – A Surprising Example

The house had a 2007 13 SEER HVAC system. Naturally, I thought that I must replace it to achieve net-zero. As it turned out, while doing the energy and financial modeling, that wasn’t the case. In my location, at least on this house, with my electric rates, and a Florida climate, adding more solar panels on the house cost less than upgrading to a new higher SEER HVAC system. By going after the cheapest and most effective energy-saving measures possible, the overall project was a success and not as big a hit on the wallet. With this approach – even with this being my first renovation ever – the total efficiency and solar energy costs equated to 6.8% of the final appraised home value, in line with the studies mentioned above.

Power for the Electric Car, Too

As a bonus, the 9.38KW solar system could, in addition to powering my home, produce enough power to drive a Tesla Model 3 for 10,000 miles per year. At the rate that my current system is producing, it is turning out to be more like 12-14,000 miles per year.

Here’s a picture from our Enphase Enlighten app, showing solar production in blue and home usage in orange throughout

the day.

Conclusion

Although there are differences between Passive House and net-zero home standards,  the end goal is nearly the same – to use as little energy as possible on a net basis.

The exciting thing is that these approaches are growing so much in popularity and have world governments behind the concept to boot. The technology is getting cheaper, the building science is getting better, and the overall economic picture makes it much more affordable to build or renovate homes more efficiently on a grand scale.

While there are so many variables with all of this, just know that there are plenty of ways to meet the goals of using less energy, reducing carbon, and building more efficiently, whether it be a passive house, net-zero, or any other way you are able to get there.

 

Erin Shine

Founder | Attainable Home

Original Article Posted on AttainableHome.com  

 

 

 

Reference

Zero Accessory Dwelling Units: Low Income Housing that Works
CategoriesSustainable News Zero Energy Homes

Zero Accessory Dwelling Units: Low Income Housing that Works

We all know there is a considerable lack of affordable housing in the U.S. and that addressing it effectively has been challenging. Now that many states and municipalities are altering their zoning to allow Accessory Dwelling Units (ADUs), there is a new opportunity to expand truly affordable rental housing – building low-cost zero energy ADUs – sometimes referred to as in-law apartments, garage apartments, attic apartments, tiny homes, or casitas. But how to make them truly affordable?

Small ADUs are Affordable

By their very nature, ADUs will cost less to rent because they are smaller, and building them uses fewer materials.  This is even more likely in an above the garage, basement, or attic ADU where existing structural elements can be used. They also have no land costs because they are built on an existing lot or above an existing garage. And there are no landscaping costs other than restoring any construction disruption. Sewer, water, and electricity are close at hand.  And, if they are zero energy ADUs, they will need no gas hook-up.  More importantly, they will have no, or almost no, energy bills for their residents.

Zero Energy Bills

There are two legs to affordability.  One is the rent – the other is the monthly utility bill. The second one is almost always overlooked when considering affordable housing, but high energy bills can play a devastating role in making an ADU rental unaffordable.  Zero Energy ADUs solve that problem and offer a more truly affordable rental.  The challenge is how to get to zero at least cost, so the rent can be kept low.

Cost Cutting Zero ADU Construction 

The first step in low-cost zero energy construction is conducting energy modeling on the planned structure.  Energy modeling will help select the lowest cost mix of energy-saving measures such as insulation and air sealing, energy-saving equipment, and solar. For example, energy modeling and price comparisons will quickly determine whether it is more cost-effective to use a heat pump water heater or add some additional panels and use a standard water heater – or whether to use insulation with a higher or lower u-value.

There are other potential savings related to the smaller size of an ADU.  Windows are expensive. Locating them to optimize light and views, and eliminating or reducing them where they are not needed, may allow smaller glazed areas. Since mini splits can be ductless, there is no need for ductwork.  Most ADUs can be heated and cooled with one small unit, which is quick and easy to install.  Since heat pump HVAC systems should never be oversized, smaller ones are usually the best choice. 

In small homes, such as ADUs, energy or heat recovery ventilation systems can be installed without ducts, using a Lunos e2 through-the-wall HRV or a Panasonic Whisper Quiet ERV to provide fresh filtered air. The size of the water heating system can be tailored to a smaller number of inhabitants. A smaller 30 or 50-gallon heat pump water heater is an excellent but more expensive option. Using a small well insulated standard electric water heater with added solar panels may be less costly. An even more economical option might be using one or two-point of use tankless electric water heaters – one in the bath and one in the kitchen – and adding sufficient solar to cover its energy use.

An ADU Solar Advantage

Another significant potential savings with constructing a stand-alone ADU is a second chance to install solar on the main property.  If the original home does not have a good solar orientation, it may be possible to orient and design an ADU with enough solar for both the original home and the ADU. Any ADU-related shed or garage can be designed to optimize solar exposure. Large roof overhangs to shade the southern or western sun to avoid overheating can also expand the solar area. Or depending on orientation, sufficient solar can be installed on the main home to supply both the main house and the ADU – or some panels can be installed on the sunniest areas of each roof. In any case, optimizing the number of solar panels will lower the cost of ownership and renting.

Small ADUs can Live Large

The key to a successful small ADU is designing it for large living.  Building inexpensive non-conditioned storage spaces outside of the conditioned ADU, either in an attached or stand-alone shed or added to a connected or stand-alone garage, is affordable and leaves room for ample storage outside and living inside.  Smart kitchen/dining areas design can provide all the amenities in a small space. Creating accessible storage spaces under stairs and over cupboards optimizes the use of space, as do multipurpose rooms like office-bedroom spaces.

Our Experience

We decided to add ADUs to our two small rental homes on two different properties in Bend, Oregon, where the city changed the code to allow ADUs. We conducted energy modeling to determine the least-cost path to zero. We sealed the building envelope using Aerobarrier and insulated it well.  We used a small heat pump mini split for HVAC and a small heat pump water heater, used one Panasonic Whisper Quiet ERV in the bath and one in the kitchen, and installed energy-efficient electric appliances, including an induction stove. We added generous unconditioned storage areas outside of each unit. Because neither of the existing small homes had a good solar orientation and the ADUs did, we added enough solar on each of the ADUs to power both the ADU and the original house on each lot. So they both became zero energy homes.

Perfect for Low Income Housing

We can profit from rents while the tenants enjoy no energy bills. We have rented out two units, with two more on the way, to people with low incomes, referred by local non-profit organizations, providing them with affordable small, well-designed living spaces with no energy bills.

By Joe Emerson

Joe is the founder of the Zero Energy Project

Reference

BlocPower: Renovating Buildings and Cities on the Path to Zero
CategoriesSustainable News Zero Energy Homes

BlocPower: Renovating Buildings and Cities on the Path to Zero

By Joe Emerson, Founder, The Zero Energy Project

Brooklyn-based BlocPower is an innovative for-profit startup that aims to renovate thousands of older buildings to become highly energy efficient, all-electric, and low–carbon emitting. All while creating good jobs for low-income people. As a “public benefit” corporation, BlocPower’s core goals include energy efficiency, renewable energy, greenhouse gas reduction, economic development, job creation in low-income communities, and financial return for its investors.

BlocPower contracts with building owners, local governments, and utilities to decarbonize residential buildings. They start by making them all-electric, removing all the fossil fuel–powered HVAC, stoves, and water heaters; replacing them with highly efficient heat pump heating and cooling systems, heat pump water heaters, and electric stoves with induction ranges. Wherever possible, they add rooftop solar or purchase renewable power for the buildings.

Making It Simple for Owners and Residents

Using advanced modeling and project-management technology, BlocPower handles the contractors; engineering and design; the equipment, removals and installations; as well as the construction loans. Sure, it’s challenging for building owners and residents to go through this process, but BlocPower does everything they can to make it easier. In addition, they provide the financing needed to pay for the project in a way that saves the owners money, usually from the very first year.

BlocPower reports that owners often save 40–60% on their utility bills after the renovation. So the annual total loan payments for the renovation are often less than the annual energy savings. As a result, even though BlocPower lends the money with interest, the owner pays less each year because of the energy savings.

Aiming High

BlocPower has a contract to electrify every residential building in the city of Ithaca within 4 years. Other cities with climate action plans are negotiating with BlocPower to assist them in decarbonizing. While they help to decarbonize a city, BlocPower hires local, low-income residents to do the work.

As an investor-backed company, BlocPower is growing its financial clout in order to scale up its building energy renovations and lending services to meet building energy efficiency needs nationwide. They systematically take advantage of all available government grants, and they’re developing Silicon Valley and Wall Street investors,  as well as crowdfunding. As BlocPower plans to go public and take their operations nationwide, they could have a massive impact on carbon emissions as they move homes and buildings across the country forward on the path to green energy.

BlocPower aims to make it possible for cities to meet their climate goals while creating a profit center for investors; creating healthier residences and workplaces; and lowering energy bills.

Reference

Elemental Green and the Zero Energy Project Join Forces to Accelerate Zero Carbon Homes.
CategoriesSustainable News Zero Energy Homes

Elemental Green and the Zero Energy Project Join Forces to Accelerate Zero Carbon Homes.

We have exciting news to share!

The Zero Energy Project has found a new home within Elemental Green, a leading green building media company dedicated to accelerating adoption of more sustainable residential building products and techniques.

By joining forces, the Zero Energy Project will reach a wider audience and have a greater opportunity to build consumer demand for zero energy and zero carbon homes, while encouraging building professionals to increase supply. Elemental Green and the Zero Energy Project, in partnership, aim to further our reach and impact – improving the discovery process for new products and professional services,  and increasing understanding of how we can build homes that are energy efficient, sustainable, and healthy.

Thank you for being part of the Zero Energy Project story and for continuing that journey jointly with Elemental Green as we all work toward creating a zero-carbon future.

Joe Emerson
Founder, The Zero Energy Project
Advisory Board, Elemental Green

Sheridan Foster
CEO, Elemental Green

Blog.

Reference