I now have almost four years of electricity and natural gas use for my house via our utility companies. We put in a heat pump in May 2022. Previously, we had two window ACs in bedrooms that we ran almost entirely at night (and only some nights) and a bunch of fans. Last summer, with intense heat, you can barely see an increase in usage—particularly when you factor in inflation and a slow climb upwards in rates. (These are all two-month billing periods and average temps.)
This winter, with some bitter cold temps for Seattle last month, it looks like we paid about 5% less with the heat pump than the same period last year. But it's likely we used substantially more therms to heat the house. (Still compiling that data; it's hard to get apples-to-apples.) This chart shows hours used for AC, heat pump heat, and nat-gas heat. (We're still using the nat-gas furnace a bit; need to consider whether turning it off turns into a maintenance problem.)
Based on sheer hours during the coldest parts of December, it's possible we saved something like $75 to $100 in fuel over two months. Hard to pay off a heat pump with those savings, but the overall comfort and the switch to mostly electrical heating and cooling for environmental reasons and efficiency, *and the elimination of all the noise in the summer from fans!* absolutely worth it.
@glennf how expensive was the heat pump and what kind of footprint does it take up? (I’m thinking of getting one for our small San Francisco home and am very curious)
@exkclamation We spent $10K for a modest house (1200 sq ft main floor; not using heat/cooling in day-lit basement) — 2-stage model. We didn't have any of the piping in place. So they had to "plumb" 40 feet of flexible piping and install the outdoor unit. They can be quite small! Ours is nearly a cube and the volume of maybe a standard refrigerator/freezer if you turned it into the cube.
@exkclamation However, we could locate the whole unit outside and tie it into an existing furnace unit that was set up to also add a heat pump. (For once, I future proofed 15 years ago when we had to suddenly replace our dead furnace.) You might do better with a ductless mini-split that has a fan inside in a unit you mount up on the top of a wall and then the outside part is much more modest.
Glenn Fleishman
kcǃ