It helps that brothers Ray and Mark Pung are electrical engineers; their zealous attention to detail and penchant for inspection results in homes that are buttoned up tight. “Our goal is to make sure we are properly inspecting our jobs and that all subs are meeting our high level of expectation,” Ray explains.
Just as important as staying on the details is making sure the green products they use will perform as promised. “We set out specs that we have to hit, and the biggest thing in such a tight house was considering types of insulation. Our was to not just take what the manufacturer claims. Because you don’t know what their baseline was for that claim. Was it slapped up or a quality job? We make sure we’re verifying our results in the field and making sure we can get good results that are in the best interest of customer.”
Insulation is one area where Ray thinks fieldwork and education can result in a superior practice. “It’s not always the most expensive option you have to use,” he says. “You’re told you have to do SIPS, you have to do spray foam, you have to spend all this money. Let’s not spend big bucks on technology, which are great in and of themselves, but that’s not for every situation.” This house was built for about $130 a square foot total.
For example, in this particular 2,856-square-foot house in Rockford, Mich., the team insulated the roof with spray foam in the penetrations, put 1” rigid foam around the can lights then sealed them with foam, and also sprayed all the divider walls. Then, they used cellulose for the rest of the job. “We used spray foam in targeted areas and less expensive cellulose to get the R-value. It’s a matter of thinking of the house as a system. Foam is great for air sealing but it is the same R-value as cellulose. Cellulose doesn’t stop air flow but is a good insulation once you’ve stopped the air with foam.”
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The Pung-owner team opted for a geothermal heat pump for this project, but only because of the tax credits. “With the 30% tax credit [on an approximately $24,500] it is only a couple thousand more than a high-efficiency natural gas furnace.” The geothermal system with a Desuperheater, also provides 70% of the home’s domestic hot water needs. “In the summer, a lower cost electric hot water heater kicks in. That heater is the storage tank for the Desuperheater.”
The value engineering the Pungs do on each house takes more work, but saves money for their customers. “If it was me, I would appreciate my builder being stewards of our money and not just using expensive materials in a shotgun approach.”
Energy Features
• Foundation: R-22 Insulating Concrete Form basement + modified frost-protected shallow foundation
• Wall Construction: 2x4 at 16" o.c.
• Wall Insulation: R-15 open cell foam + R-5 XPS exterior foam
• Rim Joist Insulation: R-15 open cell foam + R-5 XPS exterior foam
• Roof Construction: Trusses at 24" o.c.
• Ceiling Insulation: R-38 open cell spray foam + blown cellulose
• Windows: Low-e, gas-filled; U-0.31, SHGC 0.43
• HVAC: 23.7 EER, 5.0 COP geothermal heat pump; Energy recovery ventilation system
• Ducts: All supply ducts and 90% return ducts in conditioned space; Multizone distribution system
• Water Heating: Desuperheater + 0.92 EF electric auxiliary
• Lighting: 20% ENERGY STAR fixtures; 80% compact fluorescent lamps
• Appliances: ENERGY STAR refrigerator, dishwasher, and clothes washer
• On-Site Energy Generation: None
• Duct Leakage Test: 0 cfm total at 25 Pa; 0 cfm to exterior at 25 Pa
• Blower Door Test: 240 cfm at 50 Pa; 0.5 ACH50
• HERS Index: 53
• Energy/Green Building Programs: Energy Star, Green Built Michigan, LEED-H, DOE Builders Challenge qualified house