Q: Does HITS apply to new construction?
A; The HITS recipe makes it fairly easy to make money by cutting your carbon footprint dramatically on existing houses. It is far easier to do the same on a new house. This is because it cost very little more to install 6” cavity walls and fill them with insulation than it does to install 4” cavity walls. If the sheathing (plywood) outside layer is made from structurally insulated panels (which are boards made of an insulating layer like a 2” ISO board glued to a plywood structural layer which is painted in the factory to have a water proof and vapor proof layer on the outside which then has the seams between the panels taped and sealed on site) you can prevent water penetration, vapor penetration, drafts, gain rigidity and insulation in a single installation. This takes far less labor time to install than it does to install each component separately. Adding triple-glazed low-E windows costs only a few % more than double-glazed windows. Hence, it costs very little extra to build new a house with an excellent thermal envelope that will dramatically cut the carbon footprint and heating bills than it does to build a standard house. Since the heating and cooling loads are far lower than in a code-built house, the house probably needs smaller heat pumps to heat and cool the house, which saves money compared to a standard house. If the house is designed to have the back facing south with no shade then the roof can generate all the electricity needed to go zero carbon zero bills.
The moderator on our call, Bruce Sullivan, built his own house with 10” thick walls. He heats it entirely with a single air-sourced heat pump, even in the depths of winter in St. Louis. He powers the entire house with solar panels on his roof. He pays no utility bills.
While I have not built one of my own, I think the ROI on newly built zero carbon, zero bills houses is excellent.
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