Economics of Heat Pumps

Steamhead

Follow the money, folks. Who stands to benefit from programs like these?

Solid_Fuel_Man

@Voyager you sure are the only one, but that is great! Stick to it and dont let us wet heads bother you! It's ok to be an airhead!😁

@Steamhead who benefits from these programs? I've retrofitted countless (literally in the thousands) of HID lighting to LED and flourescent to LED. All of which were primarily driven by state rebates. That has saved a lot of kWh. 

I've also installed hundreds of mini-splits which have added to the grid load on a pretty linear basis. So I'd bet the net electric usage is much higher now. 

The POCO is making more money, they are selling (delivering) more watts than before. But the massive LED craze has saved lots of watts as well. 

I remember back in the 80s when the local POCO would give away electric water heaters, you just had to pay the sales tax on the MSRP of the heater. They made money there for sure. 

Also the heat pump water heaters are selling faster than wholesalers can get them in. With the state rebate they cost less than an electric one. 

Voyager

@Solid_Fuel_Man Oh, I will definitely hang around. I have learned a lot here and I enjoy the stories and banter.

And I am a BMW rider and they make airheads, oilheads and now waterheads! Although, as a K-bike rather than R-bike rider, I have always ridden a water cooled BMW. 😁

Jamie Hall

Oh come now. We can get another debate going! The only bike I ever had was an R50/5!

Solid_Fuel_Man

I passed up a '78 R80/7 when I was in college for an '82 Honda CX500. Then had a Yamaha XVS1100C. Ah...all sold now. 

Larry Weingarten

OK, I had a 1962, R 69 S. Put about 85,000 miles on it. That bike generated some stories

Yours, Larry

archibald tuttle

SuperJ said:

(but normally I'm using the wood stove).

you carbonophile you

archibald tuttle

Solid_Fuel_Man said:

Super insulation and well detailed air sealing is key.

getting insulation right definitely way more important than heat pump vs. combustion heat source. and the first thing to do if you want good insulation that last longer than your average heat pump or condensing boiler is kill all the squirrels, mice and rats within like 100 miles.

Solid_Fuel_Man

Just gotta build mouse proof. It can be done.

Funny you say that, I've shot (.22LR w/scope) at least 50 red squirrels! And more mice than that have been trapped. It took over a year to get all the little places mice can get in sealed up. Those burgers can scale anything! 

Jamie Hall

One can build mouse proof. It's not easy. It's almost impossible to mouse proof and existing structure, particularly with field stone foundations. Ask me how I know...

A couple of ambitious cats for indoors, and the .22 LR for outdoors (also good for chipmunks and squirrels). And traps. Works for me.

archibald tuttle

the scope is the thing. i used to have a pellet rifle with a dialed in scope for a 50 to 60 foot shot with the silver streak loads. that thing was deadly.

Jamie Hall

Scope makes it easy (my daughter has one on her Henry (22 LR lever action...). Me? A long barrel Colt SAA chambered for 22 LR. More sporting...

Solid_Fuel_Man

Sport has nothing to do with my relationship with the vermin..... I take every unfair advantage I can get! 

Peanut butter
Traps 
Scopes
Electricity 
Lead
Steel wool
Caulking
You name it, it's used to WIN! 

Canucker

Solid_Fuel_Man said:

Sport has nothing to do with my relationship with the vermin..... I take every unfair advantage I can get! 

Peanut butter
Traps 
Scopes
Electricity 
Lead
Steel wool
Caulking
You name it, it's used to WIN! 

I'm picturing you dressed up like Carl Spackler wandering around your property

TAG

In NJ to get the max rebates with a split system it has to be a heat pump. The incentives make the better systems cheaper vs going standard. The "clean energy" program in NJ provides high rebate levels if you follow the program. In PA they are almost nothing.

The better mini splits seem to last. I did an LG back in 06 and a Fujitsu in 2012 -- neither have been touched. My oldest Mitsubishi is only 5 years ..as is the carrier 5 speed. Again -- not touched.

The success with mini splits for heat is as much about the building as anything. Trying to heat a drafty space with a mini split is not going to work IMO. That's lots of older houses.

When I was a kid our small cape at the beach had electric heat in the plaster walls and ceilings .... like back in the womb. It was comfy .... my guess not cheap w/ NJ electric rates

SuperJ

With good heat pump options, I think going with a heat pump instead of cooling only for AC makes sense for a lot of people. Nice to have some heating options and a plan B, even if you don't like the economics of solely heating with heat pumps.

Jamie Hall

Actually, oddly, I agree -- if you are going to have AC, you might just as well have the heat pump option.

Just don't count on it to heat the place in the middle of winter...

deyrup

I think this would be a no-brainer for me if I used AC in the summer. I only get half of the savings for heating in spring and fall.

TAG

Previously, with some type of hot water heat all my houses had straight AC. Thought a waste when I had to get the HP vs straight AC in order to get the rebates and energy grant/loan .... in reality we use the HP all the time. Instant head on a cool morning when the radiant system is not on for the season ... same when I want to bump the temp up. I have also found with the zoned ducted system -- I use it to balance out any hot or cold spots.

flat_twin

Voyager said:

@Solid_Fuel_Man Oh, I will definitely hang around. I have learned a lot here and I enjoy the stories and banter.

And I am a BMW rider and they make airheads, oilheads and now waterheads! Although, as a K-bike rather than R-bike rider, I have always ridden a water cooled BMW. 😁

Well isn't that interesting, we have several air head riders here. My forum name is a carryover from BMW forums. Sold the oil heads but still have a 82 R100 in the garage.

Voyager

flat_twin said:

Voyager said:

@Solid_Fuel_Man Oh, I will definitely hang around. I have learned a lot here and I enjoy the stories and banter.

And I am a BMW rider and they make airheads, oilheads and now waterheads! Although, as a K-bike rather than R-bike rider, I have always ridden a water cooled BMW. 😁

Well isn't that interesting, we have several air head riders here. My forum name is a carryover from BMW forums. Sold the oil heads but still have a 82 R100 in the garage.

Oh the irony. I am a forced air fan and ride a water cooled K bike (K1200LT) and all of you hydronic guys ride or rode air heads. It doesn’t get any better than that! LOL.

archibald tuttle

TAG said:

Previously, with some type of hot water heat all my houses had straight AC. Thought a waste when I had to get the HP vs straight AC in order to get the rebates and energy grant/loan .... in reality we use the HP all the time. Instant head on a cool morning when the radiant system is not on for the season ... same when I want to bump the temp up. I have also found with the zoned ducted system -- I use it to balance out any hot or cold spots.

I can't disagree about heat pumps as shoulder technologies complimenting 3ish month AC function in the climate zones we're talking about (places where heating pros can make a living . . . . My finest memories of ASHRAE was walking 40 blocks through NYC to the TACO party while its 20 and snowing with John Barba in shirt sleeves. the buses were all grid locked, I offered him a coat but he wouldn't take it for which I was quietly glad.)

But one thing that is overlooked as we debate the physics in all this is that it's difficult to well capture even the marginal heat available in deeper winter because of the shrinking differential with room temperature. And if you supplement with woodstove or boiler or electric resistance back up in the heat pump system to increase room temperature that shrinks the differential even more.

So once it isn't shoulder season. unless you're willing to live with room temps of 60 and moving air I don't see how you get any advantage of the heat pump. I still think its a matter of doing the math even in shoulder season as to electric consumption times rate vs. the backup system operating with setback, i.e., one of the few times you might get condensing boiler to condense with baseboard emitters and where the relatively low temp of radiant designs kicks in. And even if you're on oil, with electrictiy having doubled (thanks in part to buying heat pumps for all comers), if your system losses aren't through the roof I wonder if the heat pump is actually saving (unless you are also driving up electric costs by hosting solar cells).

Jamie Hall

Well said, @archibald tuttle . Thank you.

TAG

Cheap electric .... it's the wild card. I don't have it.

My new house has radiant floor throughout ... zoned ducted system for AC in the main building and 3 mini splits for the addition and a loft. Even without big rebates in PA ... experience with HP at my place in NJ -- went heat pump in the ducted system.

Only have propane in PA. Since the house will initially be used on weekends I was trying to think of how to manage the fuel usage. How do I drop down the temp a bit for a couple weeks and get it up when I want to be around. The new controls solve much of this -- but, I'm just not sure how fast the radiant. I have the heat pumps .... I'm sure this would be enough with the radiant given some time. But -- for a few K more ...in went a matching modulating furnace for the ducted system. It was cheaper vs doing a fan coil off the boiler and gives me much better control. The ducted system does allow you to plug in the fuel costs (electric/ propane) and it picks the change over point.

The better heat pumps match propane costs in my area until low temps start to make the COP fall .... but, they can still give the output. Both are at best 2x + using natural gas ... and you have to keep the HP close to desired temp or the cost of setback recovery is too much and too long.

Smaller new house -- well insulated. HP's make more sense

Jamie Hall

I agree with your situation too, @TAG .

What I have said before, and will say again: there is no one correct solution for every situation. This is something which salesmen, politicians, and the advocate crowd seem to have forgotten, if they ever knew it. For space comfort, a really good heating professional should be able to analyse the specific application and determine the best solution, or selection of good solutions, for that specific situation. There are some out there...

archibald tuttle

@TAG I would think HP would be good for the time you are not there because it should be able to maintain mid 50s regardless and then you wifi your radiant to start warming up a couple days before you arrive but that is shoulder season stuff. as I more or less said above, I don't agree that "they can still give [HP]output" at low COPs in as meaningful a way unless you are at low room temp targets. As soon as you supplement their COP is going to go down even further.

There are probably some ways to store those temps like pumping them into insulated mass under the house but as with batteries for intermittent renewables I can't think of any practical ones (although it would be the minds on here who might have some idea, you could maybe have a big tank of well water coming in at 35 to 40 that you heat to 55 which isn't trivial if its a really big tank but then what do you do. how much DHW in waiting can you keep around. Or I guess you could run tap water at 55. there's legionella and what not but i don't think 55 is problematic temp. But i'm not as convinced that refrigerant to water heat exchangers have the efficient operation life of refrigerant to air. I would love to have my mind changed about that as the HP temperatures folks seek can best be found with buried geothermal and water circulation, but the heat pump and exchangers at the center of those systems are beaucoup bucks. And long horizon you need to plan to pump heat into that ground storage in the summer so if you don't have air conditioning you eventually will suffer some fall off in efficiency as you literally cool the ground over time. (i've always been interested in pairing radiant heat and radiant cooling but the dew point stuff wreaks havoc on this but maybe a system that pumps the coldest water to a dehumidifier and then the return water through the floor ? bueller . . . bueller . . . . anybody)

On the chemistry side there is the constant search for the miracle refrigerant that has the best latent heat and phase change properties but then there are all the various unintended consequences from ozone depletion to flammability and toxicity. Now i'm not as worried about those (which is not to say I don't afford them any credibility but the cost benefit on solving those problems, for the most part, was never applied any better than it is to these heat pump rebates. I'm not encouraging a return to R-12 but the fascination with getting rid of R-22 never ceases to amaze me and meanwhile the cloying bureaucrats who want to trace every ounce of it are realizing once they get rid of it they'll be out of job so they now want suppliers to track and regulate distribution of the supposedly perfect replacements such the the regulatory regime doesn't look a lot different). But the same people who worry about energy use so much also tend to worry about all these ancillary scares as well.

I just think that many of these energy saving technologies are theoretically interesting, fascinating even, but impractical in many present applications.

TAG

archibald: I'm not sure how to convince you? Modern heat pumps have the ability to not only work but provide full rated output at low temps. Under zero F -- hot air.

It's all a question of the electric cost and the actual life of the unit. Mitsubishi's first hyper was a floor unit that was sold as a replacement for a radiator.

Guess we will find out about real world life soon .... the energy programs in many states have them going in -- in big numbers.

I'm with you on the fear of reliability ..... but, I still feel that way about many of the condensing boilers. The old cast Buderus boilers I did 25+ years ago are all plugging away

hot_rod

It's all about your particular application and energy costs.

If only you could use the radiators as hot water, an air to water heat pump could be an option.

Data exists that shows, designed around a low SWT they can and do work in extreme climates, well below 0°

https://idronics.caleffi.com/sites/default/files/magazine/file/Idronics_27_na.pdf

Solid_Fuel_Man

@TAG there are many condensing boilers (munchkins etc.) still out there wheezing away and making heat efficiently.  The long term reliability for condensing equipment has proven. It's just the average tech can figure out the electronics and throws parts at them. There are many 1990s installs of condensing.....gulp.....furnaces....still working too....PVC vents and all. 

Are they less reliable...sure...but the fuel savings is HUGE over that time span. So that is the real question. At what balance do we weigh these things?

The cat is still in the bag for long term heat pump reliability. All I can say is about 1 in every 5 houses here has one, and at least 20% of them have leaked all the 410a into the atmosphere at least once from outdoor coil leaks. 

Every time we have some type of power event, my company ends up changing a bunch of circuit boards in them. Dont see that with condensing boilers/furnaces. 

This is a shot today of the heat pump graveyard in the shop. 

Right alongside of new ones in boxes. These will get fixed and reinstalled, or used for parts. Customer makes that decision. 

Jamie Hall

@TAG , while I admire your enthusiasm for heat pumps, may I, respectfully, remind you of what I said? One size does not fit all. There is a very real risk of what starts as enthusiasm for something turns, by the alchemy of politics, into a mandate. There are too many examples of this -- in too wide a range of fields -- to even begin to list them.

It is the responsibility of the enthusiast to ensure that this does not happen, by recognizing that his or her pet solution for his or her specific situation does not become a mandate. I see this happening in the environmental field. It is a responsibility to which, I am afraid, enthusiasts tend to be singularly blind.

motoguy128

I’ll add my $0.10. What we tell customers is that through a full heating season, they will reduce they bill in 1/2 over straight resistance heat. But in the coldest months (SE Iowa) it will still use mostly backup heat. Plus they get a rebate on the installation, which covers about 1/2 the up charge over central air unit.

As for lifespan. They run more. They have a defrost board that will eventually fail. I don’t think the likelihood it will develop a leak or compressor failure is higher that central air, but the condenser fan and control board add to long term costs.

That being said, with our current electric rates and natural gas rates, it’s about a 4:1 energy cost difference. 3:1 vs a steam boiler.

I have 2 of them on my house and only run them above 42F, where defrost is minimal and NET COP is over 3. Like that I get a nice even 24k BTU downstairs and 30k upstairs, and zoned, instead of 160k BTU heating the whole house at once and usually overshooting in mild weather.

If I could do it again, I’d have put central air upstairs only. The heat pump rarely ever runs upstairs.

One hidden fact, the sump heater runs all winter, spring and fall. So with a dual fuel setup, unless you kill the breaker, you are using about 50W or so all winter.