Ultra-efficient "passive house" building standards are moving from niche eco-projects into mainstream developments.The approach relies on airtight construction, heavy insulation, and heat-recovery ventilation to nearly eliminate the need for active heating or cooling. Builders who once saw it as a costly specialty are finding that prefabricated components have brought the price premium down close to conventional construction. Homeowners report utility bills a fraction of comparable homes, a selling point that's driving demand even among buyers uninterested in the environmental angle.
