Planning our solar home was a time consuming process!
This once-retired couple pondered many issues when they designed their Montana solar home. They especially considered locations close to fishing with outstanding views. They searched hard, finally finding a property that fulfilled their dreams. It even offered a great south polar exposure with great views. There was plenty of land to accommodate a sizeable house with an attached garage/shop. The extra land in front of the view would insure that no solar obstructions could be built in the future. The couple would accomplish their energy goals by actually building a true net zero home in Montana!
A heat pump for heating and cooling seemed the best choice for a solar home using solar Photo-Voltaic panels. One cannot use wood or gas if you want a true net zero home! So, to be truly net zero, we chose to design an all-electric home that would run off only solar panels.
A number of roof mounted solar panels power our electric heat pump, which was a good decision. The electric well pump conveys relatively warm well water to the heat pump which extracts heat for the radiant floor. Sadly, air to air heat pumps available at the time did not work well in Montana because of extreme temperatures.
The Climate Master is the foundation of the heating/cooling system in our solar home.
An electric furnace is not feasible for a solar home.
Solar panels were relatively expensive when we planned the house (about $1.30 compared to maybe $0.50 today). Even with today’s prices, electric furnaces require gobs of electric energy! We chose the electric heat pump to save energy and to both heat and cool our home year round. A heat pump uses about a third of the energy an electric furnace uses. For reasons explained in other parts of this section, we purchased a water-to-water heat pump.
A heat pump, water source well and a discharge well all form a system to extract geothermal energy from the ground. People call these “Pump and Dump” geothermal heating systems. It was like we discovered an oil well in the back yard when we discovered our well water was about 60F. This opened up the prospect for doing a pump and dump system with a heat pump. The heat pump extracts heat from fresh well water and dumps it into a discharge well. The discharge water temperature is maybe 12 to 18F cooler when it enters the same aquifer unpolluted by our system.
Other important design considerations for our solar home.
I divided the design process into several information tabs under this Solar Home Design parent tab. In time I expect to be continually updating my thoughts and findings regarding each of the various design subjects.
We considered many important parameters when designing the net zero energy home. Placing “(done)” below indicates the job was completed:
Passive issues affecting the performance of our solar home:
- Passive solar heating with reasonable R value, excellent fenestration (air leakage) specifications and Low E glass (done)
- Concrete floors for excellent transfer of radiant floor heat and passive solar heat storage capacity (done)
- Super insulation of floors, walls, ceiling, windows, doors and fixtures such as recessed lighting and solar tube lights (done)
- Top notch caulking and sealing against air fenestration throughout to achieve an outstanding blower door test result (done & passed)
- Extra spray foam insulation over thermal bridges, recessed lighting fixtures and top plates over walls, under soffet baffles and around
- solar lighting tubes (done)
- Special attention to using spray foam to totally surround each electrical outlet and light box plus exposed wire chase channel ends in the SIP walls (done)
- Install insulated shades and maybe drapes to reduce the winter window heat losses by as much as 30 to 60 percent (yet to be implemented)
Active solar issues considered in the design of our solar home:
- Active solar electricity production from a 10 kW peak (now 18.5 kWp) roof mounted PV (Photo-Voltaic) panel system (done)
- Heat pump conversion of electrical energy to transfer heat from our well water to our radiant floor heating water (done)
- Heat recovery and HEPA filtered outside air ventilation to avoid replacing hot indoor air with cold outside air (done)
- Install a fan between the house and garage/shop to maximize solar heat gain distribution (done)
- Utilize LED lighting throughout for super energy savings while the new low prices are hard to pass up. (done)
- Employ low-energy appliances wherever possible, especially well water pumps, refrigerators, freezers and whole house fans (done)
- Purchase a heat pump “De super heater” option to cut hot water heating energy by about 66 percent (yet to be implemented)
- Make use of fans and HEPA filters instead of the heat pump for cooling to save summer cooling costs (done)
The reader will find numerous detailed descriptions of these and more items of interest elsewhere on this site. Hopefully these ideas will contribute to any solar home construction or remodeling project.