Mastodawn

Glenn Fleishman Jan 24, 2023

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.)

Glenn Fleishman Jan 24, 2023

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.)

Glenn Fleishman

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.

Davy Buntinx Jan 24, 2023

@glennf Which heat pump, if you don't mind me asking? (We're renovating.)

Glenn Fleishman Jan 24, 2023

@dbuntinx Had to look it up! American Standard Gold 17 SEER Heat Pump
Model #: 4A7A7036A1000B

It's a 36000 BTU model, which has seemed about the right size for running it efficiently. I think if we'd gone smaller, we might have had to run it a lot more, reducing its lifespan and costing more.

Jeff Clatworthy Jan 24, 2023

@glennf Hi Glenn. Took us a bit to get our head around just how much of a difference it makes stabilising a total house’s thermoclimate with a heat pump (air conditioning). Once it’s done, there’s less temperature fluctuation, and lower overall power use required to maintain. 🙂

Glenn Fleishman Jan 24, 2023

@jeffcgd I hadn’t thought about that. A furnace is really WUMPFFFF and then pffffff cooling down. I do notice that the temperature seems more even. We love the reduction in noise. And we're not igniting fire in our house—none of that burned dust smell. (We have to figure out if we shut the furnace down entirely if we were to need it—heat pump dies and it's days to fix it—whether we could just fire it up. I should ask around.)

kcǃ Jan 24, 2023

@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)

Glenn Fleishman Jan 24, 2023

@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.

Glenn Fleishman Jan 24, 2023

@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.

kcǃ Jan 24, 2023

@glennf thank you for the info! Much appreciated!

kcǃ Jan 24, 2023

@glennf thanks! We're at 900sqft, so seems comparable!

Did you also get rid of previous heater? Or wait... (thinking) perhaps if you are in the PNW you just had baseboard heaters? We have a big box gravity-feed heater now (no blower, just heat floating up to the house), and wondering if it can take over the existing ducting.

Glenn Fleishman Jan 24, 2023

@exkclamation We're not that moderate in temp! We have a nat gas furnace with integrated heat pump coil, so they just wired that up. We didn't remove the furnace as its integral to the install. We use it now as an automatic boost in the morning then it doesn't run the rest of the day

Jemal Cole Loves Each of You Jan 24, 2023

@glennf Electrifying everything is its own reward, but the best deal going is heat pump water heaters which pay for themselves pretty quickly!

John Griffith Jan 24, 2023

@jemaleddin @glennf any suggestions on which brand heat pump hot water heater? Our current hot water tank is in the basement.

Jemal Cole Loves Each of You Jan 24, 2023

@johndgriffith @glennf not from me! There was only one model (from A.O. Smith) available in the supply chain last summer, so we took that one. In general they have slightly larger tanks and cost a little more up front, but pay for themselves in like 2 years. (My wife is an environmental economist who works in regulating energy companies, so I leave this kind of thing to her.)

Drew Pickard Jan 24, 2023

@glennf I love the idea of heat pumps, but the downer for me is the big minisplits on the walls. We're thankfully electric already so I don't know if I can sacrifice the beauty of our bare walls 😅
I guess we'll see with our next evolution of the Seattle Summer™

Glenn Fleishman Jan 24, 2023

@drewpickard We already had ductwork and I somehow had the foresight 15 years ago, when replacing a suddenly dead furnace, of buying a slightly more expensive set up with the potential to add a heat pump later. So we have an external unit between us and the neighbor’s (who got a heat pump before us!), fortunately both on the non-bedroom sides of the house. No additional ductwork inside!