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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

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 Zarkon Group,

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

A Summer Home Rebuilt on the Path to Zero
CategoriesSustainable News Zero Energy Homes

A Summer Home Rebuilt on the Path to Zero

By Zarkon Group,

The blue cottage in a historic Chautauqua community in Lakeside, Ohio, had hosted families for nearly a century and had been the beloved summer getaway of Frank and Brenda Baker’s family for the past 15 years. So when a tree fell on their summer home in June 2009, it crushed more than just the structure. At first, the Bakers hoped to save some of the original building, but a thorough inspection determined that even the areas that didn’t take a direct hit were too compromised to be reused. That news prompted the Bakers’ plan B: to rebuild the cottage from the ground up as a model of energy efficiency and sustainable building while maintaining the character of its 100-year-old  predecessor. To that end, they hired both a designer and a builder experienced in both sustainability and historic preservation.

Frank and Brenda have christened their project “The Lakeside Green Cottage” and have engaged like-minded professionals to bring it to life. Their designer, Dennis Feltner is an advocate for eco-friendly design and plans to adapt the sustainable building principles used in this home into his future work.  Additionally, the construction contractor, Tom Dearth, is a Certified Green Builder through the National Association of Homebuilders. Partnering with the  Lakeside Association’s sustainability initiative, the Lakeside Environmental Stewardship Society, the Bakers host tours of the cottage to help educate the public about the value of green renovations. “We want to show people that eco-friendly building technology and historic character can go hand-in-hand,” Frank Baker said. 

“We really think this will be an asset to the community, and perfectly aligned with the Lakeside spirit and mission, he adds. 

Sustainable Building  Measures

The Baker cottage incorporates timber frame construction, with visible posts and beams used on the first floor.  Timber trusses support the roof and create vaulted ceilings in the second-story bedrooms. They used structural insulating products for the shell of the house, incorporating structural insulating panels (SIPs), insulating concrete forms (ICFs), and flexible EPS insulation sheets. The result is a super-tight building envelope that keeps conditioned air in, vastly reducing energy use – and energy bills.

In keeping with the Baker’s sustainability goals, materials from the original cottage were reused wherever possible, including the staircase, banister, and spindles; beadboard paneling; red pine floor planks; interior doors; bathroom fixtures, and some kitchen cabinets.

Products Used

PFB® insulating building products were used throughout the Lakeside Green Cottage. The high insulating properties of the products are due to their primary component, expanded polystyrene  (EPS), a rigid foam material that has special properties due to its structure. The individual cells of low-density polystyrene make EPS extremely light and strong, able to support many times its own  weight. The individual cells prevent heat and air from moving through the EPS, making it a great insulator. 

 

Advantage ICFs were used for the foundation of the cottage. These insulated concrete forms are interlocking blocks of EPS insulation with a void in the center. Once the blocks are in place and are filled with concrete, they create a poured, insulated foundation in one step. The ICF  blocks remain in place, isolating the concrete and preventing temperature conduction from the outdoors. Plasti-Fab Durofoam flexible insulation was installed beneath the basement floor, working in concert with the ICFs to create an unbroken “envelope” below grade. The foundation walls have an R-value of 23 and the floor is R15.

 

Insulspan SIPs are an “insulation sandwich” made of two sheets of structural oriented strand board (OSB) laminated to a continuous core of expanded polystyrene insulation (EPS). The resulting panels were used for walls and roofs, allowing the structure to be erected and insulated in one step. The span of solid insulation left no room for air movement, vastly improving energy efficiency compared to traditionally framed construction methods. The vaulted ceiling had an R-value of 38. And the whole home had 1.5 Air Changes per Hour.

Structural Timbers 

Timber framing, a centuries-old construction method, uses visible timbers as the building’s structural  “skeleton.” Timber framing requires less wood than conventional construction and makes use of a renewable resource. In addition, harvesting mature, healthy trees for this purpose ensures that the CO2 the wood has absorbed stays put, rather than being released back into the atmosphere. 

Riverbend Timber Framing created the visible posts and beams that were used on the first floor, with timber trusses supporting the roof and creating vaulted ceilings in the second-story bedrooms. 

The timber was forest salvaged Douglas Fir from fire-damaged forests and thus contributed further to the sustainability of the construction.

The Home Energy Rating 

The Bakers were committed to excluding fossil fuels from their summer home. So they used electric baseboard heat, electric hot water, and an electric stove, so they no longer use natural gas in their home; and when their local grid moves to renewable energy they will be totally fossil fuel free. Because it is a summer home they initially decided that it was not cost-effective to invest in heat pump HVAC or heat pump water heating. Nonetheless, this super airtight and highly insulated 2,479 square foot home qualified for the  NAHB’s National Green Building Standard certification at the Emerald level – the program’s highest and most demanding certification, which requires a  high level of resource and energy efficiency. The original HERS rating was 68 based on projected year-round use. 

Improving the HERS Rating

Several years after the home was completed in 2010, the Bakers replaced the baseboard electric heating with heat pump mini-splits and plan to replace the standard electric water heater with a heat pump water heater. And they are planning to have their energy consultant conduct blower-door-directed air sealing to check for and remedy any air leaks that may have occurred due to settling over the last 12 years. Then they will obtain another HERS rating. They are projecting that these energy upgrades will lower their energy use significantly and they are projecting receiving a HERS rating below 50 – qualifying the home for zero energy ready status.

Zero Energy Ready

For a home to qualify as zero energy ready it must have a HERS rating of 50 or less and be capable of having all its energy needs met by renewable rooftop solar.  While the Baker’s home is designed with roof orientation, area, and slope sufficient to enable rooftop solar, adding solar panels would not be cost-effective since it is not a year-round residence. Nonetheless, the Zero Energy Ready Home status ensures that energy costs will be very low and that its operational energy use will have a minimal carbon impact. With these new ratings, the Bakers plan to continue using their home and their more recent energy-efficient upgrades to educate and inspire others to get their homes on the path to zero through the Lakeside Environmental Stewardship Society (LESS) of Lakeside Chatutauqua. 

.

By Frank Baker

Frank Baker is the founder of Riverbend Timber Framing and Insulspan in Blissfield, Michigan. He is a founding member and President of Team Zero, a non-profit organization committed to building consumer demand for zero energy and zero carbon homes. He is also the current president of LESS and advocates for renewable energy with his son Peter through his website lenaweesolar.com.

 

Reference

A Lakeside Summer Home Rebuilt on the Path to Zero
CategoriesSustainable News Zero Energy Homes

A Lakeside Summer Home Rebuilt on the Path to Zero

By Zarkon Group,

The blue cottage in a historic Chautauqua community in Lakeside, Ohio, had hosted families for nearly a century and had been the beloved summer getaway of Frank and Brenda Baker’s family for the past 15 years. So when a tree fell on their summer home in June 2009, it crushed more than just the structure. At first, the Bakers hoped to save some of the original building, but a thorough inspection determined that even the areas that didn’t take a direct hit were too compromised to be reused. That news prompted the Bakers’ plan B: to rebuild the cottage from the ground up as a model of energy efficiency and sustainable building while maintaining the character of its 100-year-old  predecessor. To that end, they hired both a designer and a builder experienced in both sustainability and historic preservation.

Frank and Brenda have christened their project “The Lakeside Green Cottage” and have engaged like-minded professionals to bring it to life. Their designer, Dennis Feltner is an advocate for eco-friendly design and plans to adapt the sustainable building principles used in this home into his future work.  Additionally, the construction contractor, Tom Dearth, is a Certified Green Builder through the National Association of Homebuilders. Partnering with the  Lakeside Association’s sustainability initiative, the Lakeside Environmental Stewardship Society, the Bakers host tours of the cottage to help educate the public about the value of green renovations. “We want to show people that eco-friendly building technology and historic character can go hand-in-hand,” Frank Baker said. 

“We really think this will be an asset to the community, and perfectly aligned with the Lakeside spirit and mission, he adds. 

Sustainable Building  Measures

The Baker cottage incorporates timber frame construction, with visible posts and beams used on the first floor.  Timber trusses support the roof and create vaulted ceilings in the second-story bedrooms. They used structural insulating products for the shell of the house, incorporating structural insulating panels (SIPs), insulating concrete forms (ICFs), and flexible EPS insulation sheets. The result is a super-tight building envelope that keeps conditioned air in, vastly reducing energy use – and energy bills.

In keeping with the Baker’s sustainability goals, materials from the original cottage were reused wherever possible, including the staircase, banister, and spindles; beadboard paneling; red pine floor planks; interior doors; bathroom fixtures, and some kitchen cabinets.

Products Used

PFB® insulating building products were used throughout the Lakeside Green Cottage. The high insulating properties of the products are due to their primary component, expanded polystyrene  (EPS), a rigid foam material that has special properties due to its structure. The individual cells of low-density polystyrene make EPS extremely light and strong, able to support many times its own  weight. The individual cells prevent heat and air from moving through the EPS, making it a great insulator. 

 

Advantage ICFs were used for the foundation of the cottage. These insulated concrete forms are interlocking blocks of EPS insulation with a void in the center. Once the blocks are in place and are filled with concrete, they create a poured, insulated foundation in one step. The ICF  blocks remain in place, isolating the concrete and preventing temperature conduction from the outdoors. Plasti-Fab Durofoam flexible insulation was installed beneath the basement floor, working in concert with the ICFs to create an unbroken “envelope” below grade. The foundation walls have an R-value of 23 and the floor is R15.

 

Insulspan SIPs are an “insulation sandwich” made of two sheets of structural oriented strand board (OSB) laminated to a continuous core of expanded polystyrene insulation (EPS). The resulting panels were used for walls and roofs, allowing the structure to be erected and insulated in one step. The span of solid insulation left no room for air movement, vastly improving energy efficiency compared to traditionally framed construction methods. The vaulted ceiling had an R-value of 38. And the whole home had 1.5 Air Changes per Hour.

Structural Timbers 

Timber framing, a centuries-old construction method, uses visible timbers as the building’s structural  “skeleton.” Timber framing requires less wood than conventional construction and makes use of a renewable resource. In addition, harvesting mature, healthy trees for this purpose ensures that the CO2 the wood has absorbed stays put, rather than being released back into the atmosphere. 

Riverbend Timber Framing created the visible posts and beams that were used on the first floor, with timber trusses supporting the roof and creating vaulted ceilings in the second-story bedrooms. 

The timber was forest salvaged Douglas Fir from fire-damaged forests and thus contributed further to the sustainability of the construction.

The Home Energy Rating 

The Bakers were committed to excluding fossil fuels from their summer home. So they used electric baseboard heat, electric hot water, and an electric stove, so they no longer use natural gas in their home; and when their local grid moves to renewable energy they will be totally fossil fuel free. Because it is a summer home they initially decided that it was not cost-effective to invest in heat pump HVAC or heat pump water heating. Nonetheless, this super airtight and highly insulated 2,479 square foot home qualified for the  NAHB’s National Green Building Standard certification at the Emerald level – the program’s highest and most demanding certification, which requires a  high level of resource and energy efficiency. The original HERS rating was 68 based on projected year-round use. 

Improving the HERS Rating

Several years after the home was completed in 2010, the Bakers replaced the baseboard electric heating with heat pump mini-splits and plan to replace the standard electric water heater with a heat pump water heater. And they are planning to have their energy consultant conduct blower-door-directed air sealing to check for and remedy any air leaks that may have occurred due to settling over the last 12 years. Then they will obtain another HERS rating. They are projecting that these energy upgrades will lower their energy use significantly and they are projecting receiving a HERS rating below 50 – qualifying the home for zero energy ready status.

Zero Energy Ready

For a home to qualify as zero energy ready it must have a HERS rating of 50 or less and be capable of having all its energy needs met by renewable rooftop solar.  While the Baker’s home is designed with roof orientation, area, and slope sufficient to enable rooftop solar, adding solar panels would not be cost-effective since it is not a year-round residence. Nonetheless, the Zero Energy Ready Home status ensures that energy costs will be very low and that its operational energy use will have a minimal carbon impact. With these new ratings, the Bakers plan to continue using their home and their more recent energy-efficient upgrades to educate and inspire others to get their homes on the path to zero through the Lakeside Environmental Stewardship Society (LESS) of Lakeside Chatutauqua. 

.

By Frank Baker

Frank Baker is the founder of Riverbend Timber Framing and Insulspan in Blissfield, Michigan. He is a founding member and President of Team Zero, a non-profit organization committed to building consumer demand for zero energy and zero carbon homes. He is also the current president of LESS and advocates for renewable energy with his son Peter through his website lenaweesolar.com.

 

Reference