There are added costs associated with extra insulation, triple-pane windows and door, the HRV system, etc. There is a reduction in the cost of the heating system which would otherwise be needed however.
This article talks more about the costs and payoff:
David- Only one home at Belfast Ecovillage has a solar thermal system for domestic hot water. Because most of the homeowners spend only $200 to $350 a year for heat, it didn't seem worth the upfront cost. None of the homes use wood heat. The builder wanted to minimize the penetrations in the building envelope and it could create air quality issues because the homes are nearly airtight.