As the sixth report in its 'Building America Best Practice Series', the US Department of Energy published a guide on using solar thermal and PV systems (attention: large pdf file!) in combination with good insulation as a best practice for zero-energy homes.
The term 'zero-energy home' is used loosely in the report to mean houses with at least 50% reduced utility bills compared to standard practice.
The combination of energy efficiency with solar is cost effective compared to conventional homes as the reduction in energy bills is larger than the increased mortgage payments from the additional investment. This is a bit misleading though, since insulation will produce the largest part of the cost savings, whereas solar consumes most of the additional investment. Still, it may make sense to a home owner to use part of the cost savings from good insulation to help finance solar technologies.
To the builder, near zero-energy homes are premium homes. They offer the benefits of being more attractive to buyers, and may command a price premium. Especially for the high-end of the housing market, the additional cost of going solar is relatively modest.
To home owners, these homes are premium homes as well - they provide a hedge against raising electricity prices. The combination of the four riders of reduced energy bills, increased environmental performance, possible increased value of property and solar subsidies provides a powerful incentive.
However, solar systems require capital, which is often in short supply when building a house, but much less so 5-10 years later. Therefore, the guide offers a checklist to make homes solar-ready for later installation: