It's taken freakin' forever to line up both contractors and complete a punch list of renovations, but today we've made some major progress towards our goal of #stopburningstuff before 2030:
Heat pumps. We moved into what we hope will be our home for the next several decades just over two years ago; a former summer-cottage-turned-house. Like many homes in the area it relied on an oil-fueled boiler and hot water radiators in every room. The boiler was installed in 1990, and while well maintained it was past its service life and not terribly efficient. The home itself was 2x4 stick-framing with R-13 fiberglass in the exterior walls. Half the house is over a crawl-space and half sits over a basement with a cement foundation.
First we spray-foamed the decking of the crawlspace (encapsulating wasn't a great option because of a giant chunk of ledge). Then we replaced two broken, double-hung single-pane windows with some casement windows that met northern energy star standards (U-factor = 0.26). "While we were at it" for window replacement we added housewrap at the sheathing level for both an air-barrier and drainage plane, and then 3" of rock wool continuous exterior insulation along one end of the house. Added furring strips to create an air-gap before installing new cedar siding (the old was rotted beyond salvation). That was all done by us over the last 10 weeks.
Today we hit another milestone; installation of heat pumps! After much load calculations and design we went with a single exterior unit which drives a single ductless heat pump in the main living space, and then a triple-unit which connects to three smaller units in the two bedrooms plus out small home office. Four zones for a 1,000 sqft home, which seems a bit crazy, but that's where we are now.
The boiler is still in place until late spring, when we will remove that and the oil tank entirely as part of the next phase of our renovations. We have about 100 gallons int eh tank and that should be the last time we ever buy heating oil. The only thing the boiler will do from now on is heat our water tank, but that will become unnecessary when we install a hot water heat pump in the coming weeks. Then the entire aging system will just be a backup this winter while we make sure everything is working properly. In all likelihood we'll have to pump most of that 100 gallons out of the tank this spring.
Meanwhile, we've got a list of air-sealing and insulating left to tackle.
$6,000 state rebate + $2,000 federal credit + $1,200 local rebate chops the total cost of the new system plus removal and decommissioning of the old system in half.