We toured a net zero house in Calgary. The house was built in 1984, and fully renovated a year ago.
They re-insulated the outside, with a spray-on vapour barrier and 4″ of insulation, coated with a finish. The windows were replaced with triple-paned windows.
The gas furnace was replaced with a heat pump, and a second heat pump for the new water tank. They hooked up to existing electrical, duct work and plumbing. The heat pump can heat or cool, but they rarely use air conditioning, as the house doesn’t heat up much in the summer.
Solar panels were installed on the garage roof. The panels produce more power than the house uses in summer, and is fed back into the grid. In winter, they buy power, at the same price as they sell it. They pay a monthly fee for the meter and access to the grid. In their first year they produced slightly more power than they used.
They expected the project to pay for itself in 25 years, but with the Alberta carbon tax coming in 2017, that payout will drop to perhaps 15 years, and continue dropping as power prices climb.
Next, they want to install another set of solar panels on the house roof, for an electric car.
We found it useful to actually see the heat pump in the utility room, with a second unit outside. The simplicity of the change from gas furnace was surprising and encouraging. We’re still waiting for some more price shifts, but we’re getting closer.