David Good and his wife Mela Breen are cofounders and the builder and principal designer, respectively, at Atmosphere Design Build in Grass Valley, California. They specialize in high-performance construction, frequently seeking net-zero energy and Passive House certifications for their design/builds. When the pair decided their next project, Good Haus, would be their family home, continuing the high-performance trend was a no-brainer and the home was built with passive-house goals in mind.
“Designing and building our own house was an opportunity to find balance and harmony between the three intersecting areas of our work: the handmade house, modern architectural forms and a commitment to high-performance building standards,” said Breen. “Everything from the window choices to the HVAC system were determined by both our performance and aesthetic goals and trying to intersect them in a harmonious way.”
The right HVAC system is essential to any high-performance home and Good Haus was no exception. Breen and Good worked with HVAC contractors Dan Perunko and Gavin Healy of Balance Point Home Performance to select an energy-efficient solution: Mitsubishi Electric Cooling & Heating Zoned Comfort Solutions®.
Designing for High-Performance
While selecting the home’s HVAC system, Good and Breen faced the challenge of conditioning a compartmentalized and multi-level space. Heating and cooling loads were calculated at roughly one ton for the entire home, but even with such low loads, they needed an HVAC system that could operate in two zones.
The Mitsubishi Electric system, using split-ductless units, offered that capability while minimizing any room-to-room variance in temperature within the zones. Perunko and Healy were able to meet climate-control goals with three ductless, wall-mounted units. Since the first level of the home spans over 60 feet, two wall-mounted units are at opposite ends to combat hot and cold spots. The total load of the downstairs units is 8,000 BTU. Upstairs, one wall-mounted unit, with a 4,000 BTU load, is likely to be used more for cooling demand.
“There may be times when just one of the smaller units is running. Despite the high summer temperatures in our area, there should be long stretches when we let the units sit idle. With our tight, well-insulated house and a typical 30-degree temperature swing at night, we can flush the house with cool night air and close it up during the day,” explained Breen.
Breen and Good also opted to pair each indoor unit with its own outdoor unit, which significantly increases the equipment’s efficiency. With a 6.5 kW photovoltaic system added to the roof, their home is on track to exceed expectations of net-zero energy consumption and produce a surplus of energy each year.
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