Heat pump in the PNW?

[travel2020]

Our furnace (17+ years old) requires some major repairs to keep it going and I’m looking into potentially replacing it instead of dealing with ongoing repairs. We currently don’t have an AC or a heat pump.

Of course, everyone I’ve called in for estimates is recommending not just replacing the furnace but adding a heat pump as it’ supposedly pays for itself over 7-8 years due to lower heating costs, and summers in the PNW are getting hotter. The cost difference is substantial at $7k for furnace vs $15k for furnace+heat pump.

I can think of 3-4 weeks each of the last few years where we could have definitely used AC but the number of weeks per year does seem to be increasing. At this point, a heat pump for cooling during the summer feels like a nice to have but not a necessity (not yet anyway). But if the cost savings are real, it might be better to get it done now vs. getting it retrofitted in a few years.

If anyone else in the PNW area has added a heat pump, please share your experience/data points.

Thanks

[seattlecyclone]

We replaced our dying furnace with a heat pump earlier this winter. It's nice to have mini-split units in some rooms so that we can control the temperatures of individual rooms more carefully. The Inflation Reduction Act provides up to a $2,000 tax credit to offset the cost of a heat pump, and rebates up to $8,000 for people on incomes less than 1.5x their local area median. I believe the tax credits are available now, while each state has to figure out its rebate program and that might not happen for several months or even into 2024. So if you're in the rebate-qualifying income range you'll probably want to wait on this upgrade until the rebates become available...unless your furnace is likely to need more than $8,000 worth of repairs to keep your house warm until then.

In terms of overall cost I really doubt the heat pump will save us money. Our furnace was the only gas appliance we had. We spent about $750 on gas in 2021. Even if electricity was free (which it definitely is not), a $750/year savings would take over a decade to recoup the price difference between your two options. Really too early to get a sense for how our electricity costs will change over the course of a year. I expect minimal cost savings there, at least in the short run.

That said we still chose the heat pump for a few reasons:
1) Our environmental impact and home fire risk are lower when we are no longer burning methane to heat our house.
2) The new mini-splits remedied some deficiencies in the prior heating system, namely no direct heat provided to the main bedroom, and insufficient heat provided to the basement.
3) Either system would be a commitment for a couple of decades. I strongly suspect that the price of natural gas is going to increase relative to the price of electricity over that time, and am placing my bets accordingly.
4) Climate change is making air conditioning less of a "nice to have." The quotes we got for a new gas furnace plus a separate air conditioner weren't too far off from the price of the heat pump. Due to the layout of our existing ductwork the mini-split heat pump was expected to be more effective at cooling than the other option.

[FINate]

What part of the PNW are you in, coastal or inland?

We're in Boise and recently replaced our HVAC. I looked into a furnace + heat pump, but our heating season is too cold for heat pumps to work efficiently, needing resistive heat strips and/or expensive geoexchange. Summers are hot, hence the AC. The only time the heat pump would make sense is during our short shoulder seasons. So we went with furnace + AC.

If we lived closer to the coast with a mild climate then I would have gone for a heat pump.

[travel2020]

We replaced our dying furnace with a heat pump earlier this winter. It's nice to have mini-split units in some rooms so that we can control the temperatures of individual rooms more carefully. The Inflation Reduction Act provides up to a $2,000 tax credit to offset the cost of a heat pump, and rebates up to $8,000 for people on incomes less than 1.5x their local area median.

Thanks, didn’t know about the Inflation Reduction Act credit. That will definitely be helpful. Doesn’t look like we would qualify for the income based rebate.

That said we still chose the heat pump for a few reasons:
1) Our environmental impact and home fire risk are lower when we are no longer burning methane to heat our house.
2) The new mini-splits remedied some deficiencies in the prior heating system, namely no direct heat provided to the main bedroom, and insufficient heat provided to the basement.
3) Either system would be a commitment for a couple of decades. I strongly suspect that the price of natural gas is going to increase relative to the price of electricity over that time, and am placing my bets accordingly.
4) Climate change is making air conditioning less of a "nice to have." The quotes we got for a new gas furnace plus a separate air conditioner weren't too far off from the price of the heat pump. Due to the layout of our existing ductwork the mini-split heat pump was expected to be more effective at cooling than the other option.

Good points about environmental impact and future considerations due to likely climate change.

Thanks.

[travel2020]

What part of the PNW are you in, coastal or inland?

We're in Boise and recently replaced our HVAC. I looked into a furnace + heat pump, but our heating season is too cold for heat pumps to work efficiently, needing resistive heat strips and/or expensive geoexchange. Summers are hot, hence the AC. The only time the heat pump would make sense is during our short shoulder seasons. So we went with furnace + AC.

If we lived closer to the coast with a mild climate then I would have gone for a heat pump.

In the Seattle area so definitely much milder climate than Boise. AC option is slightly cheaper but looks like heat pump option might work better for our area.

[chemistk]

@seattlecyclone sums up some of the most important things to consider very nicely.

I think a heat pump would work great for you, and you might even be able to consider foregoing the gas furnace completely, opting for resistive heat strips for the (very rare) occasions that you would actually use them.

I live in the Mid-Atlantic with colder winters than you. This warm winter (for us) notwithstanding, I was walking with my wife and kids yesterday and heard no fewer than two dozen heat pumps running while we were out. There are 8 houses on our street alone (ours included) that have a heat pump. Ours is more of an entry level option, and our house ~1800 conditioned sqft. The resistive strips haven't kicked on above exterior temps of ~25F, at all.

I think it's important to reiterate SC's point about the future of natural gas - residential NG, in areas that don't get brutally cold, is likely to decline over the next two decades (that is, of course, my opinion). Many municipalities (irrespective of Federal action and the hand wringing about gas stoves last month) are requiring new construction to be 100% electric, and heat pumps are almost at parity with a NG system in many places (other than operational cost). The health risks associated with long-term NG combustion in residential spaces are starting to become more obvious. It's generally more efficient to combust NG at a power-plant scale than it is to deliver it through leaky infrastructure to people's homes.

Or in other words, NG might be cheap now, but I wouldn't be surprised if it's much more expensive and much more difficult to get in certain areas in the next few decades.

[TomTX]

Heat pumps are a divisive subject, and I think that this is due to people having experience with badly designed or badly selected heat pumps from decades ago - so this myth of the ineffective heat pump was born.

A modern heat pump, appropriate to the climate should have no problems with retaining a CoP of 2 at 0F, and still work even lower without resistance/strip heaters.

As an example, the Mr. Cool Universal. North Dakota winter, heater strips disabled. Worked fine even at -24F. There are also plenty of Asian minisplits with similar performance.

https://iwae.com/resources/videos/mrcool-universal-heat-pump-heats-24-degrees.html

CoP is a measure of how effective the heat pump is, and is basically a multiplier for efficiency. A CoP of 2 means that it will heat your house 2x as much (or heat the same amount with half the electricity) as strip/resistance heaters. At milder temperatures, a CoP of up to 4 is reasonable for many heat pumps.

Personally I'd ditch the furnace and go straight heat pump. Just be sure to get an appropriate installer - these myths about heat pump performance are prevalent even among HVAC professionals.

[GilesMM]

If one is replacing a "conventional" ducted forced-air gas furnace combined with an outdoor AC condenser (inside coil) with a single heat pump system, is that cost-effective?  My 5 ton AC, 97k BTU furnace and coil cost $17k to replace.  I'm guessing a 5 ton heat pump would be around $15K?   That is about $5k for the unit and $10k for other bits and installation.  Thoughts?

[chemistk]

If one is replacing a "conventional" ducted forced-air gas furnace combined with an outdoor AC condenser (inside coil) with a single heat pump system, is that cost-effective?  My 5 ton AC, 97k BTU furnace and coil cost $17k to replace.  I'm guessing a 5 ton heat pump would be around $15K?   That is about $5k for the unit and $10k for other bits and installation.  Thoughts?

Right now that depends on quite a lot of factors -

-How old is your system? Does it need to be replaced soon?
-What kind of climate do you live in? Do you frequently experience temperatures well below 0F in the winter?
-How big is your conditioned space? How well insulated is it?
-What's the cost of natural gas where you are? Electric?
-Can you, but more importantly your family, tolerate air that's not scorching hot out of the vents?
-Do you qualify for any Federal or State tax credits?
-How climate minded are you? Do you accept higher costs for more climate friendly options?

If I threw a dart at a map that included all the places where you might live, I'd guess (especially based on the size of your conditioned space if you need a 5-Ton condenser) that unless your system is >20 years old, you're not going to be saving money anytime soon, at least if your current system could be repaired (and assuming that repair lasts a few years).

Given that, at least for the time being, NG is much cheaper than electric it's likely that your utility costs would be higher with an all-electric system. You'd certainly see improvements in the summer but the winter would be costlier.

[uniwelder]

OP should look at quotes for heat pump only, with no gas furnace.  I don't live there, but Seattle has a very mild climate. 

[travel2020]

I think a heat pump would work great for you, and you might even be able to consider foregoing the gas furnace completely, opting for resistive heat strips for the (very rare) occasions that you would actually use them.

Thanks. All the quotes I’ve had so far all only provided options for gas furnace paired with a coil and a heat pump. Didn’t know it’s possible to skip gas furnace altogether for milder climates. Will need to explore this option as a no furnace option should decrease the overall costs significantly even if we have to go with a higher end heat pump.

[travel2020]

OP should look at quotes for heat pump only, with no gas furnace.  I don't live there, but Seattle has a very mild climate.

Thank you. None of the bids so far have included heat pump only option which is interesting. Time to dig deeper and ask some clarifying questions.

[TomTX]

OP should look at quotes for heat pump only, with no gas furnace.  I don't live there, but Seattle has a very mild climate.

Thank you. None of the bids so far have included heat pump only option which is interesting. Time to dig deeper and ask some clarifying questions.

Yep. Be sure to get the CoP/temperature chart for each of the proposed units. Feel free to post/link them and we can eyeball the appropriateness. The installers may be quoting you for a crap heat pump designed in 1980.

[FINate]

OP should look at quotes for heat pump only, with no gas furnace.  I don't live there, but Seattle has a very mild climate.

Thank you. None of the bids so far have included heat pump only option which is interesting. Time to dig deeper and ask some clarifying questions.

Yep. Be sure to get the CoP/temperature chart for each of the proposed units. Feel free to post/link them and we can eyeball the appropriateness. The installers may be quoting you for a crap heat pump designed in 1980.

All good suggestions. I'll add that the Energy Star Rating was updated in 2023 to include a standard for cold climate heat pumps. This includes things like minimum HSPF and CoP at certain ambient temperatures.

That said, I think there are other variables to consider as well. We heard mixed results from neighbors with modern heat pumps, with some very happy with the performance and saving a lot of money, whereas some others who were very displeased because the heat pump struggled to keep the house warm which means they're spending a ton augmenting with resistive heating. I'm pretty sure this comes down to home size and insulation/sealing. While our house is reasonably well insulated/sealed, it's large (3200 sq ft w/ high ceilings) which is why I suspect the HVAC places all recommended dual-fuel for a heat pump solution. A 4-ton heat pump puts out around 50,000 BTU of heat, whereas the furnace we had installed puts out twice that.

I would have no hesitation about a heat-pump only installation in Seattle unless your home is unusually large or very poorly insulated/sealed.

[TomTX]

We're considering replacing the current NG furnace and 15+ year old AC (original SEER of 13) with a modern heat pump due to the incentives. If we also replace the stove/oven and water heater, we can cancel natural gas entirely and eliminate the ~$300/yr in fees just for being hooked up.