EchoHaven: A Net-Zero Community In Calgary

Walton sited the house toward the south, for good reason. The large, south-facing, energy-efficient windows have a high SHGC rating that allows solar heat to warm the home, thus reducing the need for mechanical heating. The windows bring in abundant natural light, as well, reducing the need for lighting that requires electricity (except at night, of course). The windows, in combination with a completely sealed and well-insulated building envelope, have made the home’s passive solar heating strategy possible.

The home utilizes radiant electric-heat panels developed by Thermaray. The panels are hidden behind thick drywall ceilings, allowing the drywall to capture more of the released heat. Thick drywall (5/8”) and concrete floors act as thermal mass that helps absorb and retain heat gain from the passive solar heating as well. As temperatures drop at night, the heat from the sun that was captured during the day is released into the home. Two solar thermal panels integrated into the exterior finishes supply to part of the household’s solar thermal/on-demand hot water heating.

The walls achieve an impressive R59 insulation rating—significantly higher than building code. This is achieved through three-and-a-half inches of two-pound polyurethane insulation, along with eight inches of dense-pack cellulose insulation fiber at the interior, which protects the home from frigid Calgary winters. The roof achieves a whopping R108 insulation rating. The floor is R70. The home’s passive house design, with a focus on extreme airtightness, shields the couple from the outside elements.

Energy Efficiency and Lessons Learned 

The couple has carefully documented and monitored their home’s performance since occupying it in June 2012. Home monitoring is an eligibility requirement for certification through the International Living Future Institute. To reduce their overall home electricity demand, the couple incorporated several other energy-efficiency measures.

LED lights, in combination with natural light, reduce energy demand while keeping the interior bright and lively at night. The home’s interior is light-filled, comfortable, and quiet.

A condensing, vent-less clothes dryer minimizes heat loss through the building envelope. Condensing clothes dryers help eliminate an envelope penetration for exhaust. Captured condensate can also be cleaned and used for use, such as watering plants.”

Smart ventilation, including the use of a Heat Recovery Ventilator (HRV), was required to protect the airtight house’s interior air quality. This ventilation strategy also eliminates the need for air conditioning, which reduces the home’s summer energy demand. The home also has a unique “kill switch” located in the garage. This switch essentially allows the home to be turned “off” and can drastically reduce the “ghost load” or phantom power that contributes to energy use.

International Living Future’s project write-up also notes that “Inline fans in [the] mechanical air system were an innovation to deal with bathroom moisture and kitchen exhaust and avoid envelope penetrations. The fans are activated individually by timers. Exhausts go through the HRV rather than vented directly outside. There was some concern about kitchen exhaust particulates accumulating in the HRV filter, however, this has not been the case.”