This project is a total net zero house with everything completely installed by The Radiant store: insulation, duct-work, thermal and electric solar energy, plus the Greenspeed Heat Pump and recovery ventilator.
The entire building has a tightened envelope. Closed cell spray foam insulation is applied throughout the home reducing the heating and cooling load over standard building code by 75%.
When a building is tightened up mechanical air changes are provided using a recovery ventilator to insure good air quality. The recovery ventilator gently moves air from indoors to the outdoors and replaces it with outdoor air on a set schedule. The air coming in passes through the recovery ventilator’s specially designed core to be reheated before entering the living environment.
Greenspeed Air Source Heat Pump
The most efficient air source heat pump available works in low ambient temperatures and has the highest coefficient of performance of any ASHP on the market. The Greenspeed heat pump utilizes ambient air down to 10 degrees and turns it into heated air very efficiently. For every unit of heat input, the Greenspeed produces 3 units of heat output. That is 300% efficiency.
Since the goal was to heat the house with distributed solar energy, it was important to find the most efficient Air Source Heat pump available to minimize the size of the solar array needed to accomplish the task. The Carrier heat pump co-efficiency of performance is unmatched. It boasts a HSPF rating of 12 while its closest competitor is 10.5.
Solar electric supplies enough electricity to run all of the home’s lighting, heating, and electrical needs. The sizing of the system was reduced proportionally by doing other energy conservation measures. By spray foaming the building and tightening the envelope, we reduced the electricity needed for heating. By installing solar water panels we reduced the electricity needed for water heating, and so it goes when designing a net zero home.
Solar thermal provides all the hot water for the home. By reducing electricity consumption by 5200 kilowatt hours annually, the solar hot water system allowed us to reduce the size of the solar array by 8 300 watt panels: a significant reduction in cost for the homeowner. In the final analysis, the cost of additional energy saving measures were more than offset in the reduction in the price of the solar electric system because we did not need as large of a system to produce the required power.