Frugal and Energy Efficient Living

Now they've added heat pumps. Originally it was super insulation, and stone/water/masonry energy storage. Then the industry developed double and triple window glazing, rooftop hot water energy collectors. All of this went down the tubes when REAGAN ended the energy credits on which the industry grew.

You do have to be careful with such tightly sealed houses. Building materials can off-gas toxicity, and building materials need to breathe to combat moisture buildup.

There are Ytube vids with homes in northern US with 6 or 8 inch walls filled with foam. Just no beating the investment.