Solar energy is an appealing solution to our home’s water-heating, heating, and electricity needs. Solar collectors on a roof capture people’s imagination far more readily than adding 4 inches of foam insulation to a home’s exterior. However, insulation, air-sealing, the use of efficient appliances, and providing shade to reduce air-conditioning electricity consumption will return your investment at least three times as fast as any application of solar energy.
It is prudent to reduce your energy consumption by at least 50% before investing in solar energy. Installing solar systems to a home typically provide only a fraction of the energy needed by a conventional home.
Homeowners often pay a lot of money for a solar energy system that doesn’t give them most or all the required energy because the home itself still wastes too much energy.
Passive-solar space heating contributes to the energy efficiency of many current homes with south facing windows. Optimizing the siding, windows, and shading of new homes for passive-solar heating makes perfect sense. Active solar space heating is just too expensive and complicated for widespread application.
When active-solar space heating has been successfully employed, it is combined with solar domestic water heating. The problem encountered in this combination is that you have unlimited hot water in the summer and unlimited space heat too, but you don’t need the space heat in the summer. The solar space and water heating system can get too hot in summer forcing the use of purge coils pr pressure and temperature relief valves that make the system more complex and decrease its reliability.
In the winter, when the sun is weak and low in the sky, there is barely enough solar energy to do the water heating. The space heating energy just isn’t there during the winter months unless you cover your roof and yard with expensive solar collectors.
We favor instead concentrating your initial investment on the building shell, because you can accomplish more money savings and carbon-emissions reductions with less investment by air-sealing and insulating.