Please pump me up

May 5, 2023 2:25 PM

I’d like to replace my ancient oil burning furnace with a heat pump. I have no idea where/how to start. As always…

Our house uses a stinky and expensive oil burning furnace. I’d like to replace it with a heat pump. Due to window, wall configurations, and weird layout, minisplits aren’t a good solution. So we need a whole house/central solution. I’m not sure where to start. This is in the central Puget Sound area for people who want to make specific recommendations.

- Do we start with selecting the installer or by equipment brand?
- What questions should we be asking the installer?
- What specs should we look at? Brand recommendations?
- What red flags should we keep an eye out for?
- What might the costs be for a 1400ish sqft house, mostly one floor? (ballparks here, i know this is tough to quantify)
- Any rebates or tax writeoffs to be aware of?
- Honestly anything you’d like to share that might be helpful; the good the bad the ugly.
- Our ducting sucks as well, so we are considering replacing that as well; should we roll that into this work or do at a later time?

Thanks y’all!

posted by 0xABADBABE to Home & Garden (21 answers total)

Best answer: Start with this - the Inflation Reduction Act info. Ask for good HVAC contractors from people you know. Most contractors will work with one or two brands. We replaced a furnace recently with a hybrid heat pump - has a furnace component as well because heat pumps alone aren't great with winter temps below 30F and here in Michigan we definitely get that cold. Puget Sound is mild enough you can probably get by with just a heat pump. There are two kinds of heat pumps - air and earth (or geothermal). Geothermal systems require digging - either a deep vertical well or a lot of horizontal piping. So depending on your lot it might not be a good option. We went for an air exchange one. The brands that were bid on for us were American Standard and Bryant. We went with Bryant. We got three bids and it was a little bit like comparing apples and oranges in terms of the options presented.

Heat pumps come in two varieties - two stage or multi-stage. My understanding is that the multi-stage ones come on more frequently, run less hard and are more efficient. They are often more expensive but work better and are a bit quieter. Do look at sound levels - some heat pumps are much louder and depending on where the outside unit sits you may care a lot.

I can't guess what it will cost - too different a situation from what we did. We just did this a couple months ago so can't speak to what winter will be like but the house is more comfortable, it's very quiet. Our contractor told us to not set the thermostat lower at night because that undoes the efficiencies built into a heat pump system - it has to use a lot more energy to come back up to the daytime temp so it's better to keep at a constant.
posted by leslies at 3:17 PM on May 5, 2023 [1 favorite]

Best answer: Our ducting sucks as well, so we are considering replacing that as well; should we roll that into this work or do at a later time?

You’re probably going to have to also have a new air-handler installed with the heat pump, so you might have to replace a chunk of the ductwork anyway, to get it to connect to the new air handler.
posted by Thorzdad at 3:36 PM on May 5, 2023

Best answer: Depending on where your oil tank is you will also need to factor in the cost of filling it with foam so it doesn't just corrode and leave big gaping hole in the ground or removing it per Washington State Law.

For central Puget Sound check out Evergreen Home Heating. They took over the service of my heat pumps and I've been very pleased with them.
posted by brookeb at 4:15 PM on May 5, 2023 [2 favorites]

Best answer: The material of choice in Oregon for filling decommissioned oil tanks is sand. You might consider a ductless systems if your ducts are deep in your foundation and inaccessible without serious concrete work.
posted by fiercekitten at 4:24 PM on May 5, 2023

Best answer: Yes, you have to fill in your old oil tank. Laws, safety, home value.

Our former neighbor was an HVAC guy, so he got us a deal on a Mitsubishi heat pump. Seems pretty big, but we have a mid-century split level, more sf than you, and in the downstairs all the registers are in the ceiling, lol.

I don't know if these were the folks who installed it or not, Premiere Mechanical & Electric, nor their range (Seattle here), but have been happy with their servicing us.
posted by Windopaene at 4:28 PM on May 5, 2023

Best answer: Heat pumps (the part outside) and air handlers (the part inside) are available in 1 speed, 2 speed, or variable speed models. The variable speed models are much nicer: Instead of cycling on & off, they adjust the output to the heating (or cooling) needs. This is generally much quieter, and often more efficient too. They cost a bit more, but in my opinion are worth it.
posted by soylent00FF00 at 4:49 PM on May 5, 2023

Info on heat pumps from Green Building Advisor.
posted by spamandkimchi at 5:05 PM on May 5, 2023

Best answer: Mitsubishi and Fujitsu are generally regarded as the best brands for heat pumps, especially for performance in cold weather. The American brands are generally significantly less efficient at colder temperatures. I find the Fujitsu controls are not great and people with Mitsubishi tend to be happier, but there is a significant price difference.

It can be a reasonable idea to oversize your heat pump a little bit as the cost for a larger unit is not likely to be much more and this gives you more heating capacity at colder temperatures and higher efficiency because the unit isn't working as hard.

Bear in mind that a heat pump does not heat the air up as much as an oil-fired furnace, so you will need to move significantly more air in order to heat your house (and the fan will be running fairly constantly, not on and off). If your ducts are marginal now, this will probably be a bigger problem with a heat pump. But rather than replacing the ducting, you might want to consider a ductless system, which has significant advantages (you can have multiple zones for independent control, you don't need as much space as ducts take which can make life a lot easier).
posted by ssg at 6:01 PM on May 5, 2023 [1 favorite]

Best answer: For Seattle, I would start here on the PSE rebate page. They also work with qualified contractors, so take a look at that too.
posted by dbmcd at 6:23 PM on May 5, 2023

Best answer: I concur with the above point about going a bit oversized, if you get a variable speed compressor (and I did, and I recommend it) - it doesn't have the historical problems with oversized systems (bakes the room for ten minutes then shuts off) because it will put out only as much heat as it needs to, not all the heat when it's in and none when it's off. The size of a variable speed heat pump system is the most heat it can put out, rather than the only level of heating it can do.

If you search for heat pump equipment, it's actually pretty cheap for what it is. The install is more than half the total cost - in my experience, quite a bit more. So you don't really make much of a saving by going cheap on the brand or sizing - the install is the same anyway.

My heat pump actually doesn't move much air - makes sense in a way, because it's putting out a little bit of heat and moving a little bit of air all the time rather than operating at full blast for a short period. You still want good sized ducts, though, to reduce air resistance.
posted by How much is that froggie in the window at 7:13 PM on May 5, 2023 [1 favorite]

Best answer: You’ll definitely want to seal the fill port with concrete, so that some kind of error doesn’t have an oil provider filling your basement with oil.
posted by SillyShepherd at 8:53 PM on May 5, 2023

Response by poster: ( quick reminder that ductless/mini-splits don’t work because there’s no where to mount them)
posted by 0xABADBABE at 11:59 PM on May 5, 2023

Best answer: Have your installer optimize your ducting and spend that money now, or you will likely be disappointed with the performance of the new pump, or at least not getting the maximal benefit. Remember that you also get an air conditioner now, which is a delightful surprise! We replaced our old oil furnace in a Seattle house with a mini split system and it works really well.
posted by Pantengliopoli at 1:51 PM on May 6, 2023 [1 favorite]

Mini splits also come in models which go in the ceiling or mount on wall near the floor like a radiator.

Ducting is expensive. You're probably looking at $20k-$35k assuming you're anywhere near Seattle.
posted by flimflam at 2:58 PM on May 6, 2023 [1 favorite]

Best answer: I'm in the Puget Sound area and I got a multistage heat pump and replacement gas furnace system installed last year from DVAC. I've been quite pleased with the Daikin system they installed; the heat pump takes care of the majority of our heating needs, only occasionally firing up the gas furnace on especially cold days, and AC in the summer is great to have. We had an existing forced-air system and ductwork.

I don't think our costs will be exactly comparable, but the heat pump portion I believe netted out to around $15,000 of the total cost. Since you wouldn't be installing a new gas furnace, but would be dealing with the old oil tank and potentially ductwork, there are enough different variables that you'll probably need to start getting quotes from HVAC installers to get a good sense of cost. They'll probably also be able to give better advice on options for the ductwork.
posted by Aleyn at 3:12 PM on May 6, 2023 [1 favorite]

Response by poster: fantastic answers, reached out to a few places, and we’ll see what happens. thanks all!
posted by 0xABADBABE at 1:18 PM on May 7, 2023

Best answer: There are also ducted minisplits, by the way. If your ducting is too expensive to fix, this can allow you to tuck away a unit somewhere convenient with shorter duct runs that only service one or two rooms (meaning much less ductwork, potentially).

It's going to be more expensive than a simple swap, but if you do need significant ductwork reworking, it isn't a simple swap you're looking at.
posted by How much is that froggie in the window at 6:15 PM on May 7, 2023

Response by poster: it’s good to know that minisplits can be mounted anywhere or be ducted or not, but our house is not a very open space and has poor airflow. we would need to buy one for 1) bedroom, 2) office one, 3) office two, 4) kitchen, 5) living room. i’m open if it’s a less expensive option to buy and install five minisplits, but i’m skeptical.
posted by 0xABADBABE at 10:57 PM on May 7, 2023

Best answer: The room-by-room design you mention is the typical one here in Australia with mini-splits (“heads”) off of the same base unit. We have a system with split units in the bedroom, living room, and office.

Especially in a house with poor overall circulation, this will be more efficient because you can set the individual room temperature preferences, leaving out the rooms you’re not using.

I don’t know if it’s the most efficient way to do it, but it’s rarely below freezing here, so we usually turn things off or way down when at work. But in that Australian construction codes are pretty weak, I suspect the heat would be leaking out anyway. (The joke is “Australian 5 star energy design or in the US, to code.”) Probably different in places where you want a minimum heating all the time to avoid burst plumbing from freezing…
posted by ec2y at 10:18 AM on May 8, 2023

Best answer: To add on - in my experience (Seattle house and a Winthrop house and ADU with three total heat pump installations), the outdoor units for most mini splits can usually support a maximum of 4 internal heads, so it's very likely that a 5 room setup will require two outdoor units.
posted by Pantengliopoli at 4:47 PM on May 8, 2023

Pantengliopoli - that might be dependent on the model and the system setup. My Mitsubishi has a separate five way splitter in the crawlspace (with some intelligence, I think, since it's wired in) and I think you can install two of them on the outdoor unit if you wanted to. But agreed there's always going to be an upper limit and you need to know what it is.
posted by How much is that froggie in the window at 3:32 PM on May 9, 2023 [1 favorite]