NET ZERO HOMES
Two examples of new homes with added solar panels.
Built in St. Albert, Alberta
In designing the new home in St. Albert, it was important to us to meet several primary objects. Aside from fulfilling our family and lifestyle need, it had to be approved by the Feng Shui master that we consulted throughout the design process. Secondly, it had to be net-zero, as we are committed to minimize our energy foot print.
Once the basic design was established, we worked with our builder Heiko Lotzgeselle of Rosecrest Homes, to develop building specifications to meet that goal. We had met Heiko while visiting the Eco Solar Tour in previous years. We selected Rosecrest Homes as we were impressed with the energy efficiency and quality we found in their houses on earlier Eco Solar Tours. In addition to those fundamental requirements, Rosecrest prices seemed to offer very good value.
Rosecrest, in turn engaged the services of an energy advisor to model the energy profile of our home. We went through several rounds of energy modeling, using several different components before arriving at this final combination of having a house with a very low annual energy requirement (estimated and modeled at 56 gigajoules per year) and a reasonably priced photo voltaic system mounted on the roof of our home, capable and intended to produce 56 gigajoules per year to make our home a true net zero home. As we are also planning to switch our cars to completely electric (right now I drive a hybrid S.U.V.), we hope that our PV system may provide enough electricity for these future vehicles. If not, we do have some extra space on our garage roof to add more solar panels to power our cars.
The first time we modeled the house, we had already adapted a number of energy efficient features beyond code requirements, including the following: R 80 attic insulation, R36 exterior wall insulation, R40 basement wall insulation propose 1.0 air exchange rate, 96% efficient electric furnace, 96% efficient electric hot water tank, and a dual HRV system
We found that the specifications our house would need, about 100 gigajoules per year, and that the limited roof space on our house would require a large PV system with very expensive high efficiency modules costing in the vicinity of $75K (without provincial subsidy). In response to these findings, we reduced the energy requirements of our home as follows:
Increased the attic insulation from R80 to R100.
Targeted the air exchange rate to be reduced from 1.0 /hour to 0.8/hour.
Increased the insulation for the exterior walls above ground from R36 to R40.
Increased the insulation under the basement floor by installing radon guard insulation instead of gravel under the concrete slab. The Radon Guard insulation used by us has an R factor of 8. In addition to the Radon Guard, we placed another 4” of Styrofoam insulation over top of the Radon Guard, with an additional R16 factor, yielding a total of R24 under the basement slab.
We changed the electric furnace to a zoned air sourced heat pump style furnace, specially developed to function in our climate.
We changed the standard electric water tank to a hot water tank that derives its heat molecules also from an air sourced heat pump.
With these changes our modeler predicts an energy requirement of 56 gigajoules, the energy upgrades cost us approximately $18,000. More, but we reduced the cost of the PV solar system by about $40,000, which is a substantial net saving of about $22,000., and also with roof capacity to add more panes if needed.
We would also like to mention that we worked with Rosecrest to maximize the ‘green’ aspect of our house and expect our house to be certified ‘Platinum’ under the built Green Program.
In Summary, we have created a home that we expect to be self-sufficient, in energy consumption. It cost us about $50K more to build (including PV system after provincial subsidy), but we expect our monthly energy bill to average $100/month including fuel for our future electric vehicles. We know that if we would have built this house in accordance to the present energy code, our monthly energy costs for this house would average about $440/per month. Once we plug in our cars, the fuel bill for the vehicles will reduce by about $200/month. Once we do that, our home will generate monthly savings of $540/mo. or $6500 per year. With that we will recover our initial extra expense in 9 years, but more important to us, we are helping to combat climate change while living in a healthier home.