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Nevada Energy Star Partners Demonstrate Peak Performance

September 01, 2012
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September/October 2012
This article originally appeared in the September/October 2012 issue of Home Energy Magazine.
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Las Vegas may appear balmy and inviting with its sparkling pools and swaying palm trees, but those who live in Neon City know the truth: It’s too cold in the winter and too hot in the summer.

Unfortunately, hundreds of thousands of homes that were built during an amazing 50 years of rapid growth in the Southwest do not incorporate modern advances in energy performance to accommodate the wild swings of desert climate. As temperatures climb to 110°F in the summer, many homes leak large amounts of cooled air through gaps in ducts, roofs, windows, and doors. And when the frigid north wind drops the temperature below freezing in the winter, heated air escapes, leaving living rooms and bedrooms uncomfortably cold and drafty. While Las Vegans know their climate, they may not realize that they are paying to heat and cool the great outdoors.

Carmen Boulevard demonstration home ready for ribbon cutting on February 22, 2012. (Building Media Inc.)

Carmen Boulevard home with solar hot-water panels above garage, WaterSmart landscape, low-e windows. (Building Media Inc.)

Radial design ductwork from heat pump AC system. Each duct runs to the supply plenum. (Building Media Inc.)

Ceiling view of closed-cell foam insulation under roof deck. (Building Media Inc.)

Educational display for homeowner—steps to a high-performance home.

Ducts return to plenum in closet. (Building Media Inc.)

Rick Chitwood instructing licensed HVAC contractors. (Building Media Inc.)

Student learning how to test his own work to ensure high performance. (Building Media Inc.)

Rick Chitwood demonstrates moving pressure boundary above the soffit, to include ductwork in conditioned space. (Building Media Inc.)

Carmen Boulevard WaterSmart landscape with shade structures produced out of repurposed vinyl by Repurpose America from a conference, and posts are repurposed City of Las Vegas Light Posts. (Building Media Inc.)

The dramatic temperature shifts in the high-desert climate make Las Vegas an ideal place for homeowners who are looking to make their homes more comfortable and to save substantially on their energy bills. Funded in part by DOE’s Building America program, the Building America Retrofit Alliance is working with the Nevada ENERGY STAR Partners–Green Alliance (NESP–Green Alliance), and with Better Building Performance, a Las Vegas company, to upgrade two typical homes top to bottom. Their goal has been to show homeowners and remodelers how easy and effective energy performance upgrades can be.

For the past 11 years, as a volunteer-driven nonprofit organization, NESP-Green Alliance has encouraged energy efficiency and resource preservation, and this year, EPA honored the organization with its 2011 Leadership in Housing Award for ENERGY STAR. Part of its mission has been to recognize and promote the companies, organizations, and individuals that support these efforts. NESP-Green Alliance also organizes informational meetings, seminars, and special events that promote community awareness, education, and connectivity for developing a more-sustainable Nevada.

Demonstrating Energy Efficiency in Two Model Homes

The collaborative demonstration project cited above consists of extensive upgrades to two Las Vegas homes. (For details on the upgrades, see “Deep Energy Retrofit Training—Sierra Hills Residence” and “Deep Energy Retrofit Training—Carmen Boulevard Residence.”) The Sierra, in the northwest Las Vegas Valley, is targeted to achieve 30% energy savings. The Carmen, about half a mile away, is targeted for a 50% reduction in energy use. Both homes are part of the City of Las Vegas Neighborhood Stabilization program; the goal of this program is to maintain neighborhood quality in the face of the area’s unfortunate status as the epicenter of the national foreclosure crisis.

Completed in mid-February of 2012, the two homes provide a laboratory for construction and rehabilitation techniques. They demonstrate to Las Vegas homeowners—and, eventually, to homeowners nationwide—the real-world, bottom-line benefits of energy and water efficiency upgrades, especially for people on a limited income.

The question that many homeowners bring to NESP-Green Alliance is simply this: Are these upgrades achievable and affordable? The answer is yes. With these demo homes, NESP-Green Alliance and our partners can show homeowners cost-
effective ways to make their own homes more comfortable, safe, durable, and energy efficient.

Demonstrating Partnerships

A key component of the demonstration project at all levels is collaboration among diverse organizations and government agencies. Partners include DOE’s Building America Retrofit Alliance (BARA) and the Consortium for Advanced Residential Buildings (CARB), which is documenting the efficiency upgrades. Locally, NESP–Green Alliance is joined by Better Building Performance, the City of Las Vegas, HomeFree Nevada, Green Chips, the Southern Nevada Water Authority, NV Energy, Southwest Gas, and several building contractors.

This project demonstrates the true essence of an alliance. By working with our collaborative partners, nationally and locally, we can have a much greater impact on improving residential energy efficiency than we could if each organization set out to do it alone. That may be our greatest contribution to the national conversation about ways to achieve real energy efficiency. The demonstration project is, in many ways, a soup-to-nuts operation, which explains why there are so many partners. It took the national agencies and nonprofit groups, including DOE’s Building America program, to help get the project off the ground.

Manufacturers have donated the materials for the renovation, while students—many of them contractors’ employees—have donated their labor, as part of the educational program described below. CARB, managed by Steven Winter Associates, internationally recognized experts on energy efficiency in new and existing buildings of all kinds, is providing the engineering and design for the upgrades.

Richard “Rick” Chitwood, a California-based expert on residential building performance, has been essential in training local builders and contractors to implement the upgrades in the demonstration project. Founder of Chitwood Energy Management, Incorporated, Chitwood is chairman of the California Building Performance Contractors Association Technical Committee and has written for numerous publications on energy efficiency issues.

Chitwood worked directly with the contractors in the demonstration program. Contractors’ employees received hands-on training in HVAC systems for high-performance homes and in insulation installation best practices. Employees also completed a comprehensive workshop on home sealing, ventilation, moisture control, and combustion safety. “Learning by doing—there is no better way,” says Chitwood. “I found there was, and continues to be, a high level of readiness among the contractors and their employees,” Chitwood says. “They were ready and willing to collaborate with organizations and each other to succeed. We will look back at the readiness and high level of organizational collaboration as essential elements in this program.”

The willingness of the contractors and their employees to learn from others is moving the dial past the status quo. Students in most training programs typically experience a 90-day lag between taking the training and using that training in the field. One measure of the success of our training program is that the contractors have been able to put their employees into the field almost immediately, incorporating classroom skills with hands-on application to the model homes.

My firm, Better Building Performance, has provided direct oversight of the project and the workers on both of the demonstration homes. “The training sessions with Rick Chitwood were important to the field installers, as they were able to learn on their feet while in the field and to measure their own performance, giving them the confidence to do this work in other homes,” says Brandon Kephart, president of Better Building Performance. “With Rick’s experience and knowledge, he was able to demonstrate that once they are in the home, they can enhance their software modeling strategy and performance results with field experience.”

Kephart, who has overseen the weatherization of more than 3,000 homes in Las Vegas, predicts that the modeling software used on the demonstration homes will help them achieve the efficiency targets of 30% and 50% reduction in energy use. “We’re confident that these homes will exceed the projections through the combination of excellent modeling and field experience,” Kephart says. The contractor who understands building science can recognize structural opportunities in the actual home that don’t fit into the checklist of the software, and that’s a gap that the industry is working to fill.

Installing Lennox 2-ton heat pump in conditioned space. (Building Media Inc.)

Removing old 4-ton AC system. (Building Media Inc.)

Setting up AC plenum. (Building Media Inc.)

Preparing plenum fittings. (Building Media Inc.)

Deep Energy Retrofit Training—Carmen Boulevard Residence

Many energy features are difficult to model accurately, since modelers are often required to estimate the performance of specific energy features. Here are some examples that we found in this residence:

  1. The framing on this home had many wall cavities that were open to the vented attic, turning what should be interior patrician walls into exterior surfaces.
  2. The ceiling insulation on this home was kraft-faced fiberglass batts that were installed with inset stapling. This installation technique creates a live air space between the ceiling drywall and the insulation. This convective airflow cavity can reduce insulation performance by 80%.
  3. This home has large attic knee walls. The problem described under point 2 above is even more significant on these vertical surfaces. In addition, attic knee walls are often not included at all in the energy model.
  4. The HVAC supply grille delivery velocity in this home is very low. Low delivery velocity creates temperature stratification in both summer and winter. This means that the system must run much longer to provide comfort in the occupied part of the room. The high sidewall supply grilles in this home deliver hot air at a low velocity. This hot air stays high in the room and does little to make us (and our cold feet) comfortable.

The correction of hard-to-model items found during the retrofit are likely to improve this home’s performance by 60–80%.

Project Redesign

The instructor’s field experience led to a system redesign that simplified the mechanical system. Field experience teaches us repeatedly that installing a system well is hard—very hard. To make a mechanical AC system as easy as possible to install, the system must be as simple as possible. Keeping it simple not only improves the odds of a satisfactory installation but also reduces maintenance costs.

The simplification redesign included

  1. eliminating the forced-air zoning system;
  2. reducing the number of supply grilles from nine to six by eliminating the supply grilles in the small rooms; and
  3. changing the duct design to a radial design, with each supply duct running back to the supply plenum.
Field Redesign

There were two significant field redesigns based on the more complete body of information that becomes available when the installers start to spend more time at the home and are thinking through the installation details. The installers gained the following new information:

  1. There was 1 inch of foam under the exterior stucco. This made the wall’s actual thermal performance much better than the modeled performance.
  2. The U-value used in the system design was 0.47, but the new windows will have a U-value of 0.29.
  3. The door to the master bedroom is a 5-foot double-door set.
  4. The kitchen/dining knee-wall location on the mechanical system sketch was misdrawn; it shows the kitchen area as being larger than it actually is.

This additional information made it possible to further simplify the heating-and-cooling system. The return in the master bedroom was eliminated, since the 5-foot bedroom door undercut will allow a large-enough return air path. The supply grille in the kitchen was eliminated, since the kitchen supply grille and the dining room supply grille would have only been 6 feet apart.

The final performance testing showed that both of these field redesigns were successful, since the pressure across the closed master bedroom doors was only 0.9 Pa, and there was no temperature difference between the kitchen and the dining room.

Envelope Performance

The performance of the envelope was tested with a blower door and an infrared camera. The home’s infiltration rate is currently at 4.5 ACH50, but it will come down to around 3 ACH50 when all the retrofit measures are finished. Wall thermal performance is enhanced by having 1 inch of foam under the original stucco, which was installed 28 years ago.

Ventilation

The home is ventilated with an energy recovery ventilator. Spot exhaust ventilation is provided in both bathrooms, with a 20-minute off delay.

Mechanical System Performance

A detailed list of the air-sealing performance measurements taken and the mechanical system start-up and commissioning performance measurements is posted on the Home Energy web site at homeenergy.org. Here are some of the highlights:

  • System fan energy is only 140 watts for
    870 CFM of delivered airflow (0.16 watt per CFM).
  • System static pressure is 0.27 inch water column, or about one-third of the typical
    0.81 inch WC.
  • A 3.5-ton air conditioner was replaced with a new 1.4-ton air conditioner
  • The measured net delivered Btu matched the manufacturer’s performance data.
  • The system uses only 1,610 watts (a little more than a hair dryer uses) to heat and cool this 1,521 ft2 home.
  • Duct leakage to the outside is zero. Total duct leakage is 23 CFM25.

Consumer Education and Financing Partners

After the demonstration project is completed, the contributions of HomeFree Nevada, a local 501(c)3 nonprofit, will be critical to the success of Nevada’s Home Performance with ENERGY STAR program. With support from local municipalities and the state’s Office of Energy, Nevada residents can qualify for rebates and financing to help offset the cost of improvements to their homes. To qualify for this financing, improvements must lower the homeowner’s energy costs at least 20%.

HomeFree Nevada is the statewide sponsor for Home Performance with ENERGY STAR (HPwES), a national program jointly sponsored by EPA and DOE. As the statewide sponsor of HPwES, HomeFree Nevada takes a comprehensive whole-house approach that provides training for contractors and that reaches out to homeowners with awareness and education campaigns, and incentives and financing for efficiency upgrades.

Denee Evans, HomeFree Nevada executive director, says that the collaboration with NESP-Green Alliance will help to educate the community about the benefits of making homes more comfortable and more cost-effective. “HomeFree Nevada will point to these pilot projects as hands-on examples of what individual homeowners can do to improve the quality of life in their homes and save money in the process” says Evans.

Ultimately, the success of Nevada ENERGY STAR Partners will be determined not by the energy saved in the Carmen and the Sierra but by the number of homeowners who upgrade their own houses. Increasing the demand for upgrades through public education will help promote the success of the program as well as providing ways for homeowners to afford the work. Fortunately, one of the other partners in the collaboration has helped to create a low-interest loan program for home performance upgrades. Green Chips, a nonprofit agency created through a public-private partnership, has designed a program of loans of up to $7,500 with rates as low as 2.4%, offered through the local Nevada State Bank. The loans, combined with tax credits, provide financing for owners whose homes are projected to achieve a 20% energy efficiency improvement through the initial modeling. It’s a signature loan; no equity is required. The homeowner’s savings on the utility bill are redirected to the payment of the loan, making this a win-win solution.

Green Chips has received support from some of the biggest employers in the Las Vegas Valley; major supporters include the City of Las Vegas, Harrah’s, and MGM Resorts. Through these employers’ internal communication channels and via an online portal, Green Chips plans to reach thousands of residents with the sustainability message and inform them of the financial options for creating a more energy-efficient home.

Installing new Lennox 2-ton heat pump AC system condenser to roof deck. (Building Media Inc.)

Replacing inefficient batt insulation with loose-fill fiberglass. (Building Media Inc.)

Author insulating with fiberglass to R-38. No foam used in this residence. (Building Media Inc.)

Sealing ducts to registers. (Building Media Inc.)

Deep Energy Retrofit Training—Sierra Hills Residence

Many energy features are difficult to model accurately, since modelers are often required to estimate the performance of specific energy features. In this home, a very easy envelope improvement was not modeled—moving the pressure boundary to the bottom truss cord above the bathroom and hall. This simple change brings both the attic knee walls and the ducts inside.

Project Redesign

On this project, and typically on most projects, the system design changed only because certain HVAC equipment was unavailable. The project started out with a ductless mini-split heat pump system with four terminal units. A mini-split was not available, so the design was changed to a split-system heat pump with four supply grilles and ducts in the attic, and a condensing unit on the north side of the house, outside the kitchen.

Field Redesign

There was a significant field redesign based on the more complete body of information that becomes available when the installers start to spend more time at the home and are thinking through the installation details. The installers gained the following new information:

  1. There was no attic space above the bedroom 2 closet, where the supply and return ducts were to be located.
  2. There was not enough space for the condensing unit outside the kitchen.
  3. The pressure boundary could be easily relocated to the bottom cord of the scissor trusses. This relocation simplifies the ceiling insulation installation, brings the attic knee walls inside the thermal and pressure boundaries, and creates a space for the ducts to be located inside the thermal and pressure boundaries.
  4. There was 1 inch of foam under the exterior stucco. This made the wall’s actual thermal performance much better than the modeled performance.
  5. The U-value used in the system design was 0.47, but the new windows will have a U-value of 0.29.

This additional information made it possible to improve and simplify the heating-and-cooling system. The air handler was moved from the bedroom 2 closet to the hall closet. The condensing unit was put on the roof, where the old package unit had been located. Eliminating the supply grille in the kitchen reduced the number of supply grilles from four to three. Eliminating the kitchen supply grille was possible for two reasons.

  1. The kitchen is very open to the living room.
  2. The thermal envelope is better—that is, thermal loads are smaller—than we originally thought. This is because there is foam under the stucco, because window performance is better than expected, and because we relocated the envelope to the bottom truss cord above the hall bath and the hall. This eliminated the attic knee walls and created space for the ducts to be inside.

The final performance testing showed that the field redesign was successful, since there was no temperature difference between the kitchen and the living room.

Envelope Performance

The performance of the envelope was tested with a blower door and an infrared camera. Two infrared videos, with natural pressures and depressurized, were made. The home’s infiltration rate is currently at 4 ACH50, but it will be down around 3 ACH50 when all the retrofit measures (windows, doors, and tub surrounds) are finished. Wall thermal performance was enhanced by having 1 inch of foam under the original stucco, which was installed 24 years ago.

Ventilation

The home is ventilated with an energy recovery ventilator. Spot exhaust ventilation is provided in both bathrooms, with a 20-minute off delay.

Mechanical System Performance

A detailed list of the air-sealing performance measurements taken and the mechanical system start-up and commissioning performance measurements is posted on the HomeEnergy.org web site. Here are some of the highlights:

  • Simple system: three supply grilles, no return air system.
  • MERV 16 filtration (HEPA), 4 inch pleated, is installed in the air handler filter slot.
  • System fan energy is only 185 watts for 1,000 CFM of delivered airflow (0.18 watt per CFM).
  • System static pressure is 0.13 inch water column, without the supply grilles installed. The final static will be about 0.24 inch water column after the grilles are installed, or about one-third of the typical 0.81 inches WC.
  • A 3-ton air conditioner was replaced with a new 2-ton air conditioner.
  • The measured net delivered Btu exceeded the manufacturer’s performance data by 4%.
  • The system uses only 1,535 watts (or a little more than a hair dryer uses) to heat and cool this 1,130 ft2 home.
  • Duct leakage to the outside is zero. Total duct leakage is 17 CFM25.

Models for Neighborhood Stabilization

Another goal of the collaborative demonstration project is to make homeowners aware of the energy savings they may be missing out on in their own homes. NESP-Green Alliance will reach out to southern Nevada homeowners in 2012, and the demonstration homes will be open for public viewing through May.

The model homes themselves will serve as centers for disseminating information on utility rebates, loans, state rebates, tax credits, and other opportunities to help homeowners and contractors make efficiency upgrades. Homeowners want to improve their homes’ performance. What we are doing is helping them to discover the methods introducing the many financial tools that are available, and lining them up with qualified contractors. Ultimately they will be successful in reducing their energy consumption, and they too will become part of the big-picture solution to our nation’s energy crisis.

This project demonstrates energy efficiencies that can be realized by all of our neighbors—and that, honestly, is what excites the NESP-Green Alliance partners. This project is largely about awareness—awareness among home performance contractors, but awareness among consumers
as well.

learn more

To learn more about Nevada ENERGY STAR Partners–Green Alliance, go to www.Thinkenergystar.com.

Building America Retrofit Alliance Efficient Energy Remodeling web site: www.barateam.org/eer.

Tim Whitright, development manager for the Las Vegas Neighborhood Stabilization program, sees a long-term payoff for residents and city government. “Ultimately, [energy
efficiency] is going to help people stay in their homes,” he says. “Cutting the cost of utilities makes these neighborhoods more affordable and comfortable. A stable neighborhood is more attractive to new residents and investors. That translates into sustainability at all levels.”

Darren Harris, copresident of Building Media, Incorporated, the firm representing the Building America Retrofit Alliance, says the partnerships will have a positive impact on neighborhoods in Las Vegas and across the United States. “The BARA team is focused on creating a more sustainable future by helping to improve the energy performance of existing homes, using innovations created by DOE’s Building America program,” Harris says. “The Sierra and Carmen homes are test beds that allow us to examine certain performance goals and then communicate the results to a broad audience. The net result of the energy improvements will be used to create tools and resources for professionals and consumers, so that they can retrofit homes to create peak energy performance.”

Annette Bubak is president and cofounder of Nevada ENERGY STAR Partners–Green Alliance and vice president of Better Building Performance.

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