Buildings XI Conference -- Measured Performance of Side-by-Side South Texas Homes PDF

As part of the U.S. DOE Building America program, the Florida Solar Energy Center (FSEC), CPS Energy, and Woodside Homes of South Texas are collaborating to evaluate the performance of three homes in San Antonio, Texas with identical ~2,000 ft2 floor plans and orientation. Measurements include whole house gas and electric use as well as heating, cooling, hot water, major appliances, and indoor and outdoor conditions. One home built to builder standard practice will serve as the control, while the other homes demonstrate high performance features.

These dual-fuel homes will provide utility peak electric load comparisons to assess the merit of envelope and equipment improvements. The control home uses natural gas for space and water heating only, while the improved homes have gas heating and major appliances with the exception of a high efficiency heat pump in one home.

Data collection began in July of 2009 and will continue for at least one year. Energy ratings for the homes yielded E-Scales (aka HERS indices) of 86 for the control home, 54 for one improved home and 37 for the other home which has a 2.4kW photovoltaic array. Envelope improvements include:

• Sealed attic with R-28 open cell spray polyurethane foam at the roof deck
• Frame walls insulated to R-15 + R-3 rigid insulating sheathing
• Energy Star windows, U = 0.34, SHGC = 0.33
• Enhanced air sealing

Equipment improvements include tankless gas water heaters (versus gas tank), right sized (per ACCA Manual J) SEER 18 two-stage air conditioning (versus SEER 14), Energy Star appliances, and 100% fluorescent lighting.