Image Credit: Brookside Development The insulation system starts with a 1.5-inch layer of closed-cell spray foam to seal up any cracks or holes in the exterior walls. The closed-cell foam is supplemented by 2-inch thick fiberglass batts inside the walls. The walls also have a continuous layer of 1-inch polyisocyanurate on the exterior side of the OSB wall sheathing.
Image Credit: Brookside Development The foil-faced polyisocyanurate doubles as the water-resistive barrier (WRB). Windows are flashed with peel-and-stick flashing adhered to the foil facing of the polyiso.
Image Credit: Brookside Development Before the attic insulation was installed, ceiling air leaks were sealed with expanding spray foam.
Image Credit: Brookside Development About 90% of the home's lamps are compact fluorescent lamps (CFLs). The remaining 10% are light-emitting diode (LED) lamps.
Image Credit: Brookside Development The home is EPA WaterSense certified. The kitchen faucet is a low-flow fixture.
Image Credit: Brookside Development The home has a HERS Index of 45.
Image Credit: Brookside Development The living room windows are generously sized, providing plenty of natural light.
Image Credit: Brookside Development
The builder says that the incremental cost of the energy-efficiency features was only $6,000 more than minimal compliance with the the 2009 code
Builder Mark Nuzzolo of Brookside Development has energy savings all sewn up at his new development, Singer Village in Derby, Connecticut. The high-performance homes are located on land surrounding the historic Singer House, once home of the granddaughter of Isaac Merritt Singer, founder of Singer Sewing Machines.
The first home constructed in the seven-home community earned certification from the U.S. Department of Energy’s Zero Energy Ready Home program. The program requires homes to meet a host of energy, health, and durability requirements, including those of the Energy Star Certified Homes program and the U.S. Environmental Protection Agency’s Indoor airPLUS and WaterSense programs. In addition, they must meet DOE Zero Energy Ready Home prescriptive or performance requirements and a checklist of “renewable ready” solar power measures that ensure the home is wired for a future photovoltaic (PV) array and plumbed for a future solar thermal system in case the homeowner ever wants to install them.
The home was honored with a 2013 Connecticut Zero Energy Challenge Award sponsored by the State of Connecticut. The housing development, Singer Village, was designed to meet the National Association of Home Builders’ National Green Building Standards criteria and will become the first development in Connecticut to achieve a multi-star certification. This certification recognizes the builder’s efforts to design a development that reduces storm water impact on local waterways and infrastructures, preserves native habitat and wetlands, minimizes erosion, and reduces environmental impacts during excavation and construction.
The builder got serious about energy efficiency
Nuzzolo, a veteran home builder who has built more than 400 homes over a 30-year career, has been recognized with numerous home building industry awards from the Home Builders Association of Connecticut. Although educated as a lawyer, Nuzzolo chose real estate development and has served as president of the New Haven Home Builders Association and as a current member of the association’s board of directors. He is also a Certified Green Professional. Mark’s wife, D.J. Collins, works with him as a builder, marketer, and coordinator of sales.
Nuzzolo has been participating in the Energy Star Certified Homes program since 2004. He took a serious look at increasing the energy efficiency of his homes in 2008 when oil prices rose and the recession hit hard. “I thought, we’re never going to sell a house in this market doing the same old thing. Let’s change the equation from initial cost of the home to the cost of homeownership. We decided to push the envelope,” said Nuzzolo. Nuzzolo began participating in the Energize CT New Construction Program, which offers incentives to builders who build energy-efficient homes, with tiered amounts based on the level of energy efficiency the builder achieves.
Through this program, Brookside began working with Steven Winter Associates, a research partner in the DOE Building America Program, who told Nuzzolo about the DOE Zero Energy Ready Home program. With one DOE Zero Energy Ready Home done, Nuzzolo plans to build the remaining six homes at Singer Village to meet the program criteria. “The only thing I have to figure out is making the WaterSense water distribution requirement work with all of our house designs,” said Nuzzolo. “The other requirements all make sense. Building a house this tight, you almost have to do the things Building America requires.”
According to Nuzzolo, building to the DOE Zero Energy Ready Home requirements only cost him about $6,000 more than building a home that minimally complies with the 2009 International Energy Conservation Code.
R-68 roof insulation
Nuzzolo starts with a standard 2×4 16-inch on-center wood-framed wall, and insulates between the studs with the “flash and batt” approach (1.5 inches of closed-cell spray foam, followed by unfaced fiberglass batts). “I’ve tried both open-cell and closed-cell spray foam. The closed-cell spray foam increases the strength of the wall and provides exceptional air sealing,” said Nuzzolo.
On the exterior, the 7/16 inch OSB sheathing is covered with 1 inch (R-6.5) of foil-faced polyisocyanurate rigid foam. This continuous layer of foam provides a thermal break between the framing and the siding, reducing thermal bridging through the studs.
The polyiso is taped at the seams to provide a continuous drainage plane for any rainwater that might get past the vinyl siding. The walls have a total R-value of R-25.
The vented attic has 19 inches of cellulose (R-68) piled on the attic floor. All cathedral ceilings are insulated with R-50 of closed-cell spray foam.
Heating and cooling systems are in the basement
The heating and cooling equipment is located in the basement, which is insulated from the ceiling to 3 feet below grade with R-10 of foil-faced, glass-fiber-reinforced, polyiso rigid foam insulation. (While the 2012 International Residential Code requires R-15 in this location, R-10 meets local code requirements.)
The builder chose Thermax polyiso because Thermax offers a code-accepted thermal break, i.e., building codes allow it to be left without a covering of drywall. Therefore, the basement can be left for the homeowner to finish as desired. Beneath the slab is 10 inches of packed gravel and a polyethylene vapor barrier to keep moisture out of the slab and minimize radon. There is no horizontal rigid foam under the slab.
Space heating equipment consists of an air-source heat pump with a gas furnace for back-up. The 2-ton heat pump has a heating system performance factor (HSPF) of 8 and a seasonal energy efficiency ratio (SEER) of 14. (Minimum federal appliance standards are 7.7 HSPF and 13 SEER). The high-efficiency gas furnace has an annual fuel utilization efficiency (AFUE) of 96%, far exceeding the federal minimum of 78% AFUE. The system includes a MERV 10 filter.
All of the HVAC equipment and ducts are located within the home’s conditioned space.
The heat pump works in conjunction with natural gas fuel
The builder worked with Steven Winter Associates to select the HVAC equipment and settings. They recommended setting the heat pump switch point to 50°F, which means if the outside temperature drops below 50°F, the heating system will switch to the natural gas furnace. “Analysis by Steven Winter Associates showed the heat pump lost its cost effectiveness below 50°F because we have natural gas on the site,” said Nuzzolo.
The home was designed with enough roof space and the proper orientation to permit the installation of 5 kW of PV panels. Metal conduit has been installed from the attic to the electric panel to accommodate the future installation of a PV array. “We have tremendous solar capability on the site,” said Nuzzolo. The local electric utility lets the meter spin backwards, crediting the homeowner for every kilowatt-hour produced up to the amount used by the home, at a rate of 19 cents per kilowatt-hour. But, once the meter reaches 0, any surplus electricity produced is credited back to the homeowner at 4 cents per kWh rather than 19 cents per kWh. With the dual-fuel system, the homeowner can adjust the switch point on the heat pump to rely on electric power (the heat pump) for heating after the meter has reached zero to “absorb” the excess electricity, explained Nuzzolo.
To further increase energy savings, the home is equipped with an Energy Star refrigerator and dishwasher. The lighting includes a mix of high-efficiency strategies – the exterior and interior lights that are used most often are LEDs (about 10% of the total fixtures); the remaining 90% are CFLs. There is a daylight sensor on the exterior lamp. The ceiling fan in the master bedroom is Energy Star rated. The water heater is a tankless gas water heater with an energy factor of 0.92.
Clean air measures include active and passive ventilation and low-VOC products
The home meets all of the EPA Indoor airPLUS requirements for healthy air including a passive radon venting system; low-VOC paints, finishes, and carpets; moisture management details; and an exhaust ventilation system that meets ASHRAE 62.2 ventilation requirements.
After completing his first DOE Zero Energy Ready certified home, Nuzzolo said that he enjoyed the experience and he’s learned from it. “I’ve got the expertise now. The next house we do, we’re streamlining the design and possibly reducing the size to go for a lower price point,” said Nuzzolo. “I may adjust the products and reduce the size but I don’t want to compromise the energy efficiency. Your best shot at getting an energy-efficient house is to build it that way from the start. Once the envelope is closed in, you’ve pretty much lost your opportunity.”
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Mark Nuzzolo says that building highly energy-efficient homes requires some homework, teaching ability and collaboration.
"The first hurdle to overcome is gaining the science knowledge which enables you to teach. Take a building science course, lecture, read a lot of articles. Do it more than once as it takes time to absorb. I am still learning," said Nuzzolo.
"Once you acquire the knowledge, you must commit to a strategy. Do you want to get to zero at any cost, or do you want to reach the point of diminishing returns? Either way, you must team up with a competent, experienced, and knowledgeable rater.
"After committing to a whole-house strategy, you are able to seek supply chains and subcontractors and teach, teach, teach. Also, measure everything to determine value and effectiveness," he said.
Working to high energy standards can be frustrating because the code and knowledge lags behind cutting-edge technology.
"The whole concept of green building is to reduce the demand which enables you to use fewer resources to satisfy the demand. Most challenging is saving the money and resources after lowering the demand. The industry workers beginning with engineers right down to the HVAC mechanics force you to design to current standards, partly because the codes and standards lag and partly because they have little or no experience with high performance building and lack confidence," said Nuzzolo.
"I have been doing this for some years now, and I am content with my current systems. However, technology is changing every day. You must keep pace," he added.
The benefits of green building still suffer from a lack of awareness by both the pubic and the building industry.
"This is the next biggest or maybe even the biggest challenge. Builders, realtors, appraisers and customers have very little experience with high-performance homes and therefore cannot place a value on it. The sales force needs to be very educated and passionate and demonstrative. In order to get people's attention, we have guaranteed the energy costs," he said.
"Our economy (in Connecticut) has severely lagged the nation, we have had an exodus of employers and households. We have a large amount of foreclosures and short sales which have kept prices low. Development costs, building costs, and lack of demand has kept new homes at depressed levels. It is very difficult to obtain commensurate appraisals and there is therefore little incentive to add costs to a home," said Nuzzolo.
General Specs and Team
|Climate Zone 5A, Derby, CT
Builder: Mark Nuzzolo, Woodbridge, CT, Brookside Development Rater: Steven Winter Associates, Matt Slattery
Foundation: Conditioned basement with R-10 foil-faced rigid insulation from top of wall to 3 ft. below grade; no horizontal insulation under the slab.
Walls: 1 inch (R-6.5) polyiso on exterior side of OSB sheathing; 2x4 16-in. o.c. walls with R-18 flash and batt insulation; vinyl siding.
Windows: Vinyl windows with double-pane, argon-filled, low-e glazing; U=0.28, SHGC=0.30; basement U=0.46, SHGC=0.61.
Attic: R-68 (19-in.) of cellulose on attic floor; R-50 of closed-cell spray foam in cathedral ceilings.
Heating and cooling: 2-ton air-source heat pump (HSPF 8, 14 SEER); 96 AFUE gas furnace; ducts inside, MERV 10 filter
Domestic hot water: Tankless gas; EF 0.92
Mechanical ventilation system: 90 cfm exhaust-only system that meets ASHRAE 62.2.
Lighting: 10% LED; 90% CFL; daylight sensor on exterior lamp.
Appliances: Energy Star refrigerator and dishwasher
Blower-door results: 2.03 ach50
Solar: House is pre-wired for a future PV system and plumbed for a future solar thermal system.
HERS Index: 45
Projected annual energy cost savings: $1,730
Projected annual utility costs: $2,110
Annual Energy Savings: 6,319 kWh, 654 therms gas
EPA WaterSense fixtures
Storm water management during and after construction; invasive species removed; rain garden designed to accept all runoff from home; conservation easement planned.
DOE Zero Energy Ready Home Program
EPA Indoor airPLUS
2013 Connecticut Zero Energy
NAHB National Green Building Standard, whole development