14 ms·

Heat pumps are defying Maine’s winters and oil industry pushback

99 points by anyonecancode 4y ago

FooBarBizBazz 4y ago
In terms of thermodynamic efficiency, I'd be curious about running your heat engine the other way around, by doing cogeneration on site.
Kim_Bruning 4y ago
https://web.archive.org/web/20230207123148/https://www.washingtonpost.com/climate-environment/2023/02/07/maine-gas-industry-heat-pumps/ https://web.archive.org/web/20230207123148/https://www.washi...
flyingfences 4y ago
There was a thread [0] on /r/Maine in the aftermath of the extreme cold snap last weekend, when outdoor temps dropped into the negative double digits, where people chimed in on how their heat pumps held up. By and large, they confirmed that the manufacturers' claims are correct -- they do keep working (albeit less efficiently) down to the rated temperatures and in some cases even below. The winning strategy, at least up here, seems to be a cold-weather heat pump (commonly rated to -10F) for normal baseline heat and a woodstove to fill in when it gets really cold or the power goes out. [0] https://old.reddit.com/r/Maine/comments/10t0yd9/heat_pumps_in_the_cold/ https://old.reddit.com/r/Maine/comments/10t0yd9/heat_pumps_i...
- pfdietz 4y ago
  I like these schemes where two solutions with different performance metrics are combined that cover each others weak points. Other examples are RAM and cache memory, and short term (battery) and long term/backup (hydrogen) energy storage.
  - AstralStorm 4y ago
    Hydrogen is terrible backup storage, as it evaporates through all known materials. Even as metal hydride or ammonia it's not great. (Density for the first, stability for the latter.) This is why everyone still uses hydrocarbons. Pity they don't make or burn them cleanly.
    - pfdietz 4y ago
      Hydrogen for backup storage for the grid would be stored underground. This is a demonstrated working technology.
      - AstralStorm 4y ago
        Underground in what? Leaky container or an even more leaky cave? There is a reason why there are low levels of hydrogen even in oil fields, while there are high levels of methane...
        pfdietz 4y ago
        Underground in geological formations. For example, in cavities solution-mined out of salt. This is a known and proven technology. Despite your pearl clutching, the hydrogen doesn't escape at a rate that would make it unworkable.
- londons_explore 4y ago
  For 'enthusiasts', a dual heat source system is a good plan. But regular folk want to just pay the energy bill and have a warm home, whatever the weather outside. They don't care to worry about lighting the wood stove on super cold days. They don't want to have to have a wood delivery separate from their energy bill, and be carting it around in boxes. They don't want to huddle into the room with the wood stove because the rest of the house is too cold. Regular folk aren't interested in heating systems, so will pay a small premium for a system that just works, whatever the weather.
  - aidenn0 4y ago
    There is no modern system that "just works" whatever the weather. We had an ice storm when I was growing up and lost power for 3 days. Wood stove worked great as a backup, not much else would have.
    - hedora 4y ago
      Dual source heatpump + Solar + battery + propane generator might be OK. The batteries would need to somehow be kept warm though. (The solar and battery are there to stretch out the propane supply until the delivery truck gets past whatever road blockages exist, and then addresses the inevitable shortage cause by the electricity going out.) Of course, an 80% efficient wood stove costs a small fraction as much as the above setup, and is more reliable.
      - flyingfences 4y ago
        > The batteries would need to somehow be kept warm though. If I were buying such a setup, I'd just put the batteries in the basement. Plenty of space, and it stays 40-50°ish year-round here.
        adql 4y ago
        Not that many homes are built with basements nowadays. Water to water heat pump with pipes being directly under building's basement might've been pretty neat solution tbh, if you're digging for basement anyway might as well put some piping there for the heat pump
- tclancy 4y ago
  Here in NH it took a while to get warm but it worked. And it was cold enough the generator didn’t start. Which obviously made having a second source of heat in the interim important.
- pen2l 4y ago
  In addition to this, I think we should go back to doing things the hard way, the old-school way: adapt and adjust your lifestyle to temperature changes like our ancestors did. Let the temperature dictate your cooking: do the dishes that require oven use, that require you to have 3 stoves on at the same time (and crucially, avoid these dishes in the summer!). Go on a bulk in the winter time so that you are more resilient to cold with that extra weight on you (and go on a cut in the summer). Set the temperature a little colder, put on a sweater, do more physical work. This is how the human body has evolved! - to be able to do withstand a little bit of cold, to sometimes be hungry for a long time. Always adjusting your environment for the absolute peak levels of comfort is probably not doing you any good and the heat pump's limitations are not that bad in this regard. I think letting your life revolve around customs is fun as well as a biological necessity to some degree. If you skip the chance to test it out and let it face a challenge every now and then, you're not doing yourself favors. This elderly gentleman can make it fine alone in Yakutia where temperatures can reach as low as about -100 deg F, you probably can as well: https://www.youtube.com/watch?v=IOltGIaDPlY https://www.youtube.com/watch?v=IOltGIaDPlY
  - hammock 4y ago
    Your ideas are good for today, however I question how accurate they are for "our ancestors." Most people in e.g. the colonial days didn't have an oven - they went to the town baker to use theirs when needed. They also didn't have three stoves and all the pots and utensils required to use them simultaneously
    - deleted 4y ago
      [deleted]
    - ravel-bar-foo 4y ago
      While three stoves was probably ahistorical for most homes, a fire which heats the home and is also used to cook (food in ceramic containers) was absolutely commonplace. In particular, a controlled cooking fire in the center of a single-room thatched-roof home was the template for much of Europe, Asia, and for some of the North American natives, albeit at different points in their history.
- adql 4y ago
  Don't they just start working essentially as effective resistive heater below some temperature ? So theoretically just oversizing it a bit should've been enough for the once in 10 years cold snap event. Woodstove with some supplies probably cheaper than oversizing tho
  - Kon-Peki 4y ago
    I've heard that with heat pumps you want to be very careful about getting the sizing correct. So if your plan is to get a heat pump and improve home insulation you need to do the insulation part first so you don't end up with an oversized heat pump. This is, basically, my plan out here in the midwest. I want a wood burning stove insert into my fireplace, improved insulation, and finally a heat pump. Long term I'll completely eliminate natural gas.
  - uuddlrlrbaba 4y ago
    And far warmer
  - thehappypm 4y ago
    No, at some point they’re worse than resistive.
    - timbit42 4y ago
      I've heard some heat pumps have a resistive heater in them which is used if the heat pump's CoP goes below 1.
  - sbradford26 4y ago
    So many people will say that but even at -13F the LG Red heat pump I have is rated for a COP of ~2. Which means it is still twice as efficient as a resistive space heater. Now capacity does fall off and that can cause issues since heating demands rise as temperature drops but that is an initial design constraint that just has to be designed around. NEEP has a great website to find all kind of specifications for heat pumps. Below is the link to the unit we have at our house in Southern New Hampshire. https://ashp.neep.org/#!/product/53914/7/25000///0 https://ashp.neep.org/#!/product/53914/7/25000///0
fallingfrog 4y ago
I have an oil furnace as a backup, but my oil furnace pooped out and the heat pump kept working during the recent cold snap. I think it's because they ran the pipe for the forced hot water from the oil furnace right up against the wood timbers of the foundation in contact with the outside, and they froze in that spot. So I wound up just running the heat pumps.
ttul 4y ago
Frankly the best and most entertaining, overly detailed and nerdy discussion of heat pumps is on this YouTube channel: https://youtu.be/7J52mDjZzto https://youtu.be/7J52mDjZzto
- jagermo 4y ago
  heat pumps are one of the best examples for science = magic.
1970-01-01 4y ago
We need more stories like this. Installing a heat pump is a win for everyone except big oil and gas. Reasons for refilling an oil tank must be harder and harder to justify every time. Perhaps one day we can repurpose our buried gas pipelines into wire conduits.
ben7799 4y ago
I'd somehow expect some paid pro-oil/gas/propane commenters to show up in these comments and tell us we're all wrong, no different then the industry plants going out to these people in the article! My house has natural gas.. two setups that are both really complicated. Each unit has failed in the past during extreme weather. Fossil fuel heating units are certainly not immune to failure any more than heat pumps are.
ilamont 4y ago
I live outside of Boston, about two hours south of Portland Maine. We have a LG Heat Pump installed in 2021, consisting of the following: LG/LG LMU360HHV Outdoor Unit 2 LG LSN180HSV5 Indoor Units 2 LG LMN079HVT Indoor Units We also have a natural gas furnace, now rarely used ... except when it gets really cold. During the deep freeze I wanted to see how low the LG could go before the gas furnace kicked in. The house is 100+ years old, with updated insulation in the basement and roof as of 2021 (required to get a no-interest loan on the heat pump in our state). On Friday, as the temp dropped, we set the units to 70 degrees F (21C). At 1 pm it was 15F outside (-10C) and the interior temp was 62F (17C). It was able to maintain that interior temp until 9:30 pm when the thermometer dropped to -3F (-20C) at which point the interior edged down to 60F and the furnace kicked in. The heat pump continued to work all night, albeit blowing lukewarm air. At 6 am it was still dark and the outside temp had dropped to -11F (-24C) and the heat pump was still working but the gas furnace was doing most of the work to keep the interior at 60F. On a local FB group, people shared their heat pump stories. A few only had heat pumps with no backup and reported the interior temp dropped to the 40s or low 50s (~10C). One person said that one of their two outside units froze during the night (I believe the result of condensation forming). Regardless of the type of heat, many people all over the city had burst pipes in their walls, ceilings, and basements, including several hospitals.
- sbradford26 4y ago
  We are in southern NH and have a single LG LMU480HHV for our house. Our house was built in 1973 and is ~1600 sq ft. The heat pump kept the house right at 64-65F when set to 66F through the night even when we hit -15F. Now I have backup heat strips but due to some config issue they are not currently working so that was all heat pump.
- nemo44x 4y ago
  > Regardless of the type of heat, many people all over the city had burst pipes in their walls, ceilings, and basements, including several hospitals. It's amazing how many people simply don't take basic precautionary measures when extreme cold is on the way. Something as basic as letting the faucets drip will prevent freezing. Shutting off the water and opening the taps works too if you don't want to "waste water". > A few only had heat pumps with no backup and reported the interior temp dropped to the 40s or low 50s (~10C). A good case for not using heat pumps if you live in a place that can have extreme cold snaps. I have a heatpump for 2 bedrooms but if it stopped working then opening the doors and letting the warm air from the furnaces in would be enough I think. I'd be skeptical of having only a heatpump.
acidburnNSA 4y ago
Perhaps ironically, oil fired generators have to fire up to supply enough electricity for these cold snaps. Low-carbon nuclear, high-carbon fracked gas, and high-carbon oil are the three largest sources of electricity in Maine during deep freezes. https://www.themainewire.com/2023/02/amid-cold-snap-maines-electricity-comes-from-nuclear-natural-gas-and-fossil-fuels/ https://www.themainewire.com/2023/02/amid-cold-snap-maines-e...
- mkozlows 4y ago
  It's not that ironic. Electrification isn't a "welp, we're done now, yay" thing, it's one of two parallel paths that works together for decarbonization. 1. Electrify all the things 2. Clean up the electrical supply Obviously if you only look at one of the paths in isolation, it doesn't solve problems ("it's great that everything's electric, but electricity is still high carbon"/"it's great that electricity is clean, but most energy use isn't electric"), but there's no path forward on climate that doesn't involve both.
  - acidburnNSA 4y ago
    Why electrify all the things instead of decarbonize all the things? Lots of places use zero carbon nuclear district heating to take advantage of the hot water for building heat. It can be pumped 100 km from the plant as it is at Beznau. This makes nuclear more cost effective as well since you're using a valuable product (heat) that is otherwise wasted.
    - twobitshifter 4y ago
      The idea of nuclear power plants in the US near residential communities is a non-starter. Solar thermal or geothermal might be an option, but I believe heat pumps outperform those options on cost.
      - acidburnNSA 4y ago
        How is it a non-starter? Nuclear plants are low-carbon and extremely safe [1]. 100 km is a long way. There are millions of people in the USA living within 100 km of a nuclear plant. Showing people the numbers on nuclear isn't that hard. [1] https://ourworldindata.org/safest-sources-of-energy https://ourworldindata.org/safest-sources-of-energy
londons_explore 4y ago
I worry about the 'futureproofness' of heat pumps. Specifically, heat pumps use more energy on cold days. They use a massive amount more energy on the coldest days. Today, if you use double the electricity, it costs double the money. Thats affordable as long as it happens rarely. But, with lots of people getting EV's and heat pumps, and the generation mix getting more wind and solar, I forsee energy companies forcing customers onto dynamic pricing plans. Ie. the price adjusts every hour of the day. Now when it's cold, and everyone else is trying to use extra power for their EV's and heat pumps, the price will go way up. So now, instead of using double the power and paying double, you'll use double but pay 50x. Suddenly the economics of a heat pump don't look so attractive when you realise you paid $300 on one cold night... Dual heat sources solve this (I doubt gas will ever have dynamic hourly pricing).
- Scoundreller 4y ago
  Retrofit market is still huge, especially in Maine where people mostly Don’t have natural gas connections and therefore don’t have a monthly standby charge for that. When you already have a Woodstove, pellet stove, oil heat or propane heat for the cold snaps, yeah, the economics really pushes in favour there.
- mkozlows 4y ago
  Whether electric companies have that kind of pricing isn't a pure economics question, it's a question of what regulators will alow, and I'm pretty skeptical that regulators would allow that. But "how does the grid handle spikes in demand" is the really interesting question there, and why more transmission lines (to smooth out supply/demand geographically) and reliable sources of "firm" power are important. Energy storage at scale is potentially really important here, too (and one of the reasons why home batteries are more important to the grid in some ways than home solar).
  - coryrc 4y ago
    It's not about regulators, it's that you need something rarely, but it's capital costs aren't less than something you need often, so it's going to be really expensive for the short time you need it. Even if you spread the cost out over the year, consumers are paying it one way or another. Our only plan for seasonal change in production and demand is to over-build gas turbines.
rsynnott 4y ago
I find all this fear mongering about heatpumps in the US currently to be a little odd, because they've been popular in some cold countries in Europe for some time. If there was going to be a problem, there would already have been a problem.
- throwaway894345 4y ago
  Does Europe have cold countries? According to some quick Googling, the average winter temperature in Norway is still warmer than in Iowa (a not-particularly-cold state). (FWIW I think heat pumps are interesting, I drive an electric car, etc--I'm not speaking from some reflexively anti-electrification ideological position)
  - rsynnott 4y ago
    Northern Scandinavia gets pretty cold. Various parts of Europe also have exceptional extremely cold weather; the average isn't _really_ what you want to think about when it comes to heating systems (well, it matters, in that it's relevant to the cost structure, but you really want your system to be able to deal with the reasonable edge-case weather).
    - throwaway894345 4y ago
      Yeah, it's a crude metric for sure, but we have to make sure we're making a good comparison before claiming "If there was going to be a problem, there would already have been a problem." Notably, some Googling indicates that heat pumps aren't effective below -13F which can be the high temperature in Iowa (never mind colder states) for week on end. Are heat pumps common in parts of Scandinavia that get this cold (or colder)?
  - magicalhippo 4y ago
    From what I can see Des Moines[1] and Oslo[2] are fairly comparable, and here in Oslo it's quite common to have air to air heat pumps. Mind you, Oslo is quite south in Norway, it's much colder further north. [1]: https://www.weather.gov/wrh/climate?wfo=dmx https://www.weather.gov/wrh/climate?wfo=dmx (annual) [2]: https://seklima.met.no/months/max(air_temperature https://seklima.met.no/months/max(air_temperature P1M),mean(air_temperature P1M),min(air_temperature P1M)/recurring_period/SN18700/nb/2003-01-01T00:00:00+01:00;2023-01-31T23:59:59+01:00
AbrahamParangi 4y ago
Heat pumps are obviously great but the enthusiasm for regulating Green technology into housing design seems to me to trade the interests of the poor for the interests of the upper middle class.
- anovikov 4y ago
  Short-term interests of the poor, that is. On the next round, when non-renewable energy will become really scarce, poor won't be able to heat their homes at all without "green technology".
  - AbrahamParangi 4y ago
    Easy to say “this is what you should want” when it’s really what I want.
    - jobs_throwaway 4y ago
      what do you mean by that
beamgirl 4y ago
My dad is a retired heat and power engineer up in Maine (20something years at a paper mill). We probably spent half of Christmas talking about his new minisplit. He has been tracking his electricity bill and heating oil bills in spreadsheets for years. He still has the old oil boiler in place for emergencies, but as far as I know he hasn't had to use it yet this year. He said he wanted more data before he made a definitive statement about the savings, but initial results seemed pretty promising even in the cold spells we've had
- zdragnar 4y ago
  To be fair, pretty much anything would save money over heating oil, including just burning money.
  - sbradford26 4y ago
    I know it is sarcastic but there is a website where you can calculate how much it would cost to heat with dollar bills. https://coalpail.com/fuel-comparison-calculator-home-heating https://coalpail.com/fuel-comparison-calculator-home-heating
    - beamgirl 4y ago
      Coalpail is a really handy site. They've got all the hookups on the cheap coal distributors. The guy I buy from isn't listed, you just call him and ask for an appointment to meet him at his coal shed.
    - zdragnar 4y ago
      Where on earth did they get $250 for a cord of wood? Unless you're buying them 10-13 logger's cords at a time, then cutting and splitting it yourself, a cord of oak around where I live (which is not at all far from oak trees) is in the $450-550 range. You can maybe push it down to $300/cord if you know a guy, but then you're not getting properly seasoned stuff, you're getting stuff recently cut from a dead tree left standing for a few years.
overreg 4y ago
Are these air to air systems? Retrofitting heat pumps for air to water central heating, as is normally done in the UK, is really expensive and rarely makes economic sense for an individual household.
- twobitshifter 4y ago
  They are air to air. The hydronic heat pumps are not common in the US AFAIK, but I’d love to hear if anyone has found an affordable solution.
  - hedgehog 4y ago
    They are less common but available, I have just recently been looking at options that will do combined hydronic heat and hot water for the taps. The hardware isn't too expensive but the labor for that kind of install can be a lot (highest number I got estimated was $60k).
- stanleydrew 4y ago
  These seem to be mostly so-called "mini-splits" which are air to air ductless systems.
- fundad 4y ago
  Yes
sharemywin 4y ago
Even if we had discounts at the pump to subsidize things I wish different costs like environmental costs were added to the price so people could at least see the the true price to make decisions
hedora 4y ago
What a fitting anti-electrification PR campaign for the 120th anniversary of Edison intentionally (allegedly, and perhaps fraudulently) electrocuting a homicidal elephant to teach us of the dangers of alternating current! https://science.howstuffworks.com/innovation/science-questions/why-did-thomas-edison-electrocute-elephant.htm https://science.howstuffworks.com/innovation/science-questio... Anyway kids, remember, every time your heat pump spins up, Dumbo’s mom dies. Now, drink up the fuel oil the nice man in the red suit delivered last Christmas. It’ll put hair on your chest. More info (warning: graphic images): https://en.m.wikipedia.org/wiki/Electrocuting_an_Elephant https://en.m.wikipedia.org/wiki/Electrocuting_an_Elephant
- 1234letshaveatw 4y ago
  Edison was advocating Direct Current, not fuel oil?
suls 4y ago
What’s the cost of a kWh in Maine? The newer houses here in Japan tend to be all-electric (water, stove, AC) and the current prices (~¥40/kWh) make a lot wish for kerosene heaters of the past decades.
- flyingfences 4y ago
  (40 JPY is .304 USD today) Most of Maine is paying .264 USD/kWh this winter.
losvedir 4y ago
I know heat pumps are all the rage on HN these days, but I looked into them for myself in Indiana, and they don't seem to make financial sense at all, unfortunately. My utility, NIPSCO, charges $0.25699/therm for gas. There are 29.3 kWh of energy in 1 therm of gas, and my furnace is 95% efficient, so this works out to an electric equivalent of $0.009/kWh. That's more than an order of magnitude cheaper than the electric equivalent! Even a really efficient heat pump isn't going to be able to overcome that. Am I doing the calculations wrong, or are my utility rates way out of whack, or are heat pumps just generally more expensive for everyone to run, but they still think it's worth it? I'm trying to understand how my situation is so different, because I was pretty excited about swapping out my gas furnace for a heat pump and went down that rabbit hole quite a ways before realizing my specific utility rates don't seem to make sense for it.
- loudmax 4y ago
  Heat pumps don't just convert electricity into heat. They work like an air conditioner in reverse, concentrating heat from outside into your house. Compared to a traditional heating element they're over 100% efficient.
- timmg 4y ago
  The thing with heat pumps is that they don't create heat, they pump it. So they are "more than 100% efficient" (meaning: they move more heat than what the equivalent energy is).
- trynewideas 4y ago
  > My utility, NIPSCO, charges $0.25699/therm for gas Well, there you go. Natural gas in Maine is $1.95 to $3.58 per therm. https://www.maine.gov/energy/heating-fuel-prices https://www.maine.gov/energy/heating-fuel-prices
- strgcmc 4y ago
  I don't understand how you can compare the price of gas (which you convert into an equivalent $/kWh price, no issues so far), with the price of electricity, without trying to account for how long or how often either heating system has to run for... it's almost certainly not the same amount of time. For example, let's imagine an experiment where 2 heating systems are tasked with doing the same thing -- let's say, to keep a 2000 sq ft home at an even 70F degrees, when the outside air temperature is 0F while the ground temp is whatever-it-is: - How much gas would the gas system consume, over how many hours, to maintain that 70F temp? Maybe it uses X1 amount of gas, over Y1 hours, for Z1 price of gas, so you can multiply that out. - How much electricity would a heat pump consume, over how many hours? Maybe it uses X2 amount of electricity, over Y2 hours, for Z2 price. You're only comparing Z1 and Z2, how could that possibly tell you the whole story? Heat pumps can be >100% efficient (I've seen claims of up to 300% efficiency in ideal conditions), while gas maxes out at about 95%, so I don't know why you wouldn't try to measure/estimate the X and Y variables too, and why you'd only focus on the Z.
jakedata 4y ago
Heat pump electrical usage does not go up as the temperature drops. In fact the actual heat pump itself uses less electricity because the compressor needs to slow down in order to scavenge the outdoor heat needed to vaporize the refrigerant. What causes a spike in electrical usage is the backup resistive heat source that kicks in when the compressor cannot satisfy the demand for heat. Installing a heat pump that is engineered and properly sized for extreme cold will prevent this issue. My heat pump does not have a backup resistive heater and I can watch the compressor cycle in realtime on my Sense Home Energy Monitor. The pattern is quite obvious once you understand what you are looking at. -edit- power consumption tracks the heat load in normal temp ranges, I am referring to the backup heat source turning on during extreme cold.
- thehappypm 4y ago
  Incorrect, efficiency drops as the temperature differential grows. This is a basic law of thermodynamics, since you can extract energy from a temperature difference, it must require energy to create one.
  - jakedata 4y ago
    Absolutely true - efficiency drops. Electrical consumption also drops if your heat exchanger can't scavenge enough heat from the air to vaporize your refrigerant. The compressor must slow down. Or as I pointed out - you can activate a backup heat source which causes a huge spike in electrical usage. Probably better than freezing however.
    - thehappypm 4y ago
      Most heat pumps don’t have a backup built in anymore, though. I have 2 (LG and Mitsubishi) and neither has a resistive backup built in.
      - timbit42 4y ago
        My heat pump is 11 years old and doesn't have a resistive heater. I thought resistive heaters were a new thing. Many people in the Northern US and Canada need some kind of backup and a resistive heater in the heat pump would be a selling point for many.
efitz 4y ago
What gets me is why so many localities are pushing or requiring electrification when the grid in many areas is already overloaded. For goodness sake California has fairly regular rolling blackouts and yet many cities are banning gas hookups. The right energy tech, IMO, is “all of them”.
- bryanlarsen 4y ago
  California's grid falls down in the summer time during peak air conditioner use. It has spare capacity in the winter time.
mytwocentsworth 4y ago
Related heatpump info for the DIY crowd: Homemade Heat Pump Manifesto (2009) [1]. Although factors such as extreme cold-weather performance will be compromised, the lower cash outlay confers considerable appeal to this approach. > My initial goal was to make available the knowledge and possibility that anybody with a few tools and gumption could convert discarded air conditioners, and dehumidifiers into very high efficiency heat sources, or cooling sources. Through the years, we have received reports of success from many people, living in many states, and countries. [1] https://news.ycombinator.com/item?id=32959850 https://news.ycombinator.com/item?id=32959850
subpixel 4y ago
Electricity prices have jumped about 50% this year in Maine, so the calculations many used when installing heat pumps are way off. https://www.pressherald.com/2022/11/16/power-supply-rates-for-most-cmp-customers-to-rise-again-in-2023/ https://www.pressherald.com/2022/11/16/power-supply-rates-fo...
- flyingfences 4y ago
  https://archive.is/VnYRJ https://archive.is/VnYRJ
upsidesinclude 4y ago
Any engineers feel like running the heat calcs on whether it's actually more beneficial to have the heat exchanger in a small enclosed space heated by the wood stove? Im curious if the efficiency of the heat pump would allow for minimally heating the condenser to keep within the operating range. That space might only be heated to +10°F, but would allow for the heat pump to operate normally.
giardini 4y ago
The bare insulation in the roof shown in the photograph gives me the heebie-jeebies.

99 points by anyonecancode 4y ago

In terms of thermodynamic efficiency, I'd be curious about running your heat engine the other way around, by doing cogeneration on site.

Kim_Bruning 4y ago

https://web.archive.org/web/20230207123148/https://www.washingtonpost.com/climate-environment/2023/02/07/maine-gas-industry-heat-pumps/ https://web.archive.org/web/20230207123148/https://www.washi...

flyingfences 4y ago

There was a thread [0] on /r/Maine in the aftermath of the extreme cold snap last weekend, when outdoor temps dropped into the negative double digits, where people chimed in on how their heat pumps held up. By and large, they confirmed that the manufacturers' claims are correct -- they do keep working (albeit less efficiently) down to the rated temperatures and in some cases even below. The winning strategy, at least up here, seems to be a cold-weather heat pump (commonly rated to -10F) for normal baseline heat and a woodstove to fill in when it gets really cold or the power goes out. [0] https://old.reddit.com/r/Maine/comments/10t0yd9/heat_pumps_in_the_cold/ https://old.reddit.com/r/Maine/comments/10t0yd9/heat_pumps_i...

pfdietz 4y ago
I like these schemes where two solutions with different performance metrics are combined that cover each others weak points. Other examples are RAM and cache memory, and short term (battery) and long term/backup (hydrogen) energy storage.
- AstralStorm 4y ago
  Hydrogen is terrible backup storage, as it evaporates through all known materials. Even as metal hydride or ammonia it's not great. (Density for the first, stability for the latter.) This is why everyone still uses hydrocarbons. Pity they don't make or burn them cleanly.
  - pfdietz 4y ago
    Hydrogen for backup storage for the grid would be stored underground. This is a demonstrated working technology.
    - AstralStorm 4y ago
      Underground in what? Leaky container or an even more leaky cave? There is a reason why there are low levels of hydrogen even in oil fields, while there are high levels of methane...
      - pfdietz 4y ago
        Underground in geological formations. For example, in cavities solution-mined out of salt. This is a known and proven technology. Despite your pearl clutching, the hydrogen doesn't escape at a rate that would make it unworkable.
londons_explore 4y ago
For 'enthusiasts', a dual heat source system is a good plan. But regular folk want to just pay the energy bill and have a warm home, whatever the weather outside. They don't care to worry about lighting the wood stove on super cold days. They don't want to have to have a wood delivery separate from their energy bill, and be carting it around in boxes. They don't want to huddle into the room with the wood stove because the rest of the house is too cold. Regular folk aren't interested in heating systems, so will pay a small premium for a system that just works, whatever the weather.
- aidenn0 4y ago
  There is no modern system that "just works" whatever the weather. We had an ice storm when I was growing up and lost power for 3 days. Wood stove worked great as a backup, not much else would have.
  - hedora 4y ago
    Dual source heatpump + Solar + battery + propane generator might be OK. The batteries would need to somehow be kept warm though. (The solar and battery are there to stretch out the propane supply until the delivery truck gets past whatever road blockages exist, and then addresses the inevitable shortage cause by the electricity going out.) Of course, an 80% efficient wood stove costs a small fraction as much as the above setup, and is more reliable.
    - flyingfences 4y ago
      > The batteries would need to somehow be kept warm though. If I were buying such a setup, I'd just put the batteries in the basement. Plenty of space, and it stays 40-50°ish year-round here.
      - adql 4y ago
        Not that many homes are built with basements nowadays. Water to water heat pump with pipes being directly under building's basement might've been pretty neat solution tbh, if you're digging for basement anyway might as well put some piping there for the heat pump
tclancy 4y ago
Here in NH it took a while to get warm but it worked. And it was cold enough the generator didn’t start. Which obviously made having a second source of heat in the interim important.
pen2l 4y ago
In addition to this, I think we should go back to doing things the hard way, the old-school way: adapt and adjust your lifestyle to temperature changes like our ancestors did. Let the temperature dictate your cooking: do the dishes that require oven use, that require you to have 3 stoves on at the same time (and crucially, avoid these dishes in the summer!). Go on a bulk in the winter time so that you are more resilient to cold with that extra weight on you (and go on a cut in the summer). Set the temperature a little colder, put on a sweater, do more physical work. This is how the human body has evolved! - to be able to do withstand a little bit of cold, to sometimes be hungry for a long time. Always adjusting your environment for the absolute peak levels of comfort is probably not doing you any good and the heat pump's limitations are not that bad in this regard. I think letting your life revolve around customs is fun as well as a biological necessity to some degree. If you skip the chance to test it out and let it face a challenge every now and then, you're not doing yourself favors. This elderly gentleman can make it fine alone in Yakutia where temperatures can reach as low as about -100 deg F, you probably can as well: https://www.youtube.com/watch?v=IOltGIaDPlY https://www.youtube.com/watch?v=IOltGIaDPlY
- hammock 4y ago
  Your ideas are good for today, however I question how accurate they are for "our ancestors." Most people in e.g. the colonial days didn't have an oven - they went to the town baker to use theirs when needed. They also didn't have three stoves and all the pots and utensils required to use them simultaneously
  - deleted 4y ago
    [deleted]
  - ravel-bar-foo 4y ago
    While three stoves was probably ahistorical for most homes, a fire which heats the home and is also used to cook (food in ceramic containers) was absolutely commonplace. In particular, a controlled cooking fire in the center of a single-room thatched-roof home was the template for much of Europe, Asia, and for some of the North American natives, albeit at different points in their history.
adql 4y ago
Don't they just start working essentially as effective resistive heater below some temperature ? So theoretically just oversizing it a bit should've been enough for the once in 10 years cold snap event. Woodstove with some supplies probably cheaper than oversizing tho
- Kon-Peki 4y ago
  I've heard that with heat pumps you want to be very careful about getting the sizing correct. So if your plan is to get a heat pump and improve home insulation you need to do the insulation part first so you don't end up with an oversized heat pump. This is, basically, my plan out here in the midwest. I want a wood burning stove insert into my fireplace, improved insulation, and finally a heat pump. Long term I'll completely eliminate natural gas.
- uuddlrlrbaba 4y ago
  And far warmer
- thehappypm 4y ago
  No, at some point they’re worse than resistive.
  - timbit42 4y ago
    I've heard some heat pumps have a resistive heater in them which is used if the heat pump's CoP goes below 1.
- sbradford26 4y ago
  So many people will say that but even at -13F the LG Red heat pump I have is rated for a COP of ~2. Which means it is still twice as efficient as a resistive space heater. Now capacity does fall off and that can cause issues since heating demands rise as temperature drops but that is an initial design constraint that just has to be designed around. NEEP has a great website to find all kind of specifications for heat pumps. Below is the link to the unit we have at our house in Southern New Hampshire. https://ashp.neep.org/#!/product/53914/7/25000///0 https://ashp.neep.org/#!/product/53914/7/25000///0

fallingfrog 4y ago

I have an oil furnace as a backup, but my oil furnace pooped out and the heat pump kept working during the recent cold snap. I think it's because they ran the pipe for the forced hot water from the oil furnace right up against the wood timbers of the foundation in contact with the outside, and they froze in that spot. So I wound up just running the heat pumps.

ttul 4y ago

Frankly the best and most entertaining, overly detailed and nerdy discussion of heat pumps is on this YouTube channel: https://youtu.be/7J52mDjZzto https://youtu.be/7J52mDjZzto

jagermo 4y ago
heat pumps are one of the best examples for science = magic.

1970-01-01 4y ago

We need more stories like this. Installing a heat pump is a win for everyone except big oil and gas. Reasons for refilling an oil tank must be harder and harder to justify every time. Perhaps one day we can repurpose our buried gas pipelines into wire conduits.

ben7799 4y ago

I'd somehow expect some paid pro-oil/gas/propane commenters to show up in these comments and tell us we're all wrong, no different then the industry plants going out to these people in the article! My house has natural gas.. two setups that are both really complicated. Each unit has failed in the past during extreme weather. Fossil fuel heating units are certainly not immune to failure any more than heat pumps are.

ilamont 4y ago

I live outside of Boston, about two hours south of Portland Maine. We have a LG Heat Pump installed in 2021, consisting of the following: LG/LG LMU360HHV Outdoor Unit 2 LG LSN180HSV5 Indoor Units 2 LG LMN079HVT Indoor Units We also have a natural gas furnace, now rarely used ... except when it gets really cold. During the deep freeze I wanted to see how low the LG could go before the gas furnace kicked in. The house is 100+ years old, with updated insulation in the basement and roof as of 2021 (required to get a no-interest loan on the heat pump in our state). On Friday, as the temp dropped, we set the units to 70 degrees F (21C). At 1 pm it was 15F outside (-10C) and the interior temp was 62F (17C). It was able to maintain that interior temp until 9:30 pm when the thermometer dropped to -3F (-20C) at which point the interior edged down to 60F and the furnace kicked in. The heat pump continued to work all night, albeit blowing lukewarm air. At 6 am it was still dark and the outside temp had dropped to -11F (-24C) and the heat pump was still working but the gas furnace was doing most of the work to keep the interior at 60F. On a local FB group, people shared their heat pump stories. A few only had heat pumps with no backup and reported the interior temp dropped to the 40s or low 50s (~10C). One person said that one of their two outside units froze during the night (I believe the result of condensation forming). Regardless of the type of heat, many people all over the city had burst pipes in their walls, ceilings, and basements, including several hospitals.

sbradford26 4y ago
We are in southern NH and have a single LG LMU480HHV for our house. Our house was built in 1973 and is ~1600 sq ft. The heat pump kept the house right at 64-65F when set to 66F through the night even when we hit -15F. Now I have backup heat strips but due to some config issue they are not currently working so that was all heat pump.
nemo44x 4y ago
> Regardless of the type of heat, many people all over the city had burst pipes in their walls, ceilings, and basements, including several hospitals. It's amazing how many people simply don't take basic precautionary measures when extreme cold is on the way. Something as basic as letting the faucets drip will prevent freezing. Shutting off the water and opening the taps works too if you don't want to "waste water". > A few only had heat pumps with no backup and reported the interior temp dropped to the 40s or low 50s (~10C). A good case for not using heat pumps if you live in a place that can have extreme cold snaps. I have a heatpump for 2 bedrooms but if it stopped working then opening the doors and letting the warm air from the furnaces in would be enough I think. I'd be skeptical of having only a heatpump.

acidburnNSA 4y ago

Perhaps ironically, oil fired generators have to fire up to supply enough electricity for these cold snaps. Low-carbon nuclear, high-carbon fracked gas, and high-carbon oil are the three largest sources of electricity in Maine during deep freezes. https://www.themainewire.com/2023/02/amid-cold-snap-maines-electricity-comes-from-nuclear-natural-gas-and-fossil-fuels/ https://www.themainewire.com/2023/02/amid-cold-snap-maines-e...

mkozlows 4y ago
It's not that ironic. Electrification isn't a "welp, we're done now, yay" thing, it's one of two parallel paths that works together for decarbonization. 1. Electrify all the things 2. Clean up the electrical supply Obviously if you only look at one of the paths in isolation, it doesn't solve problems ("it's great that everything's electric, but electricity is still high carbon"/"it's great that electricity is clean, but most energy use isn't electric"), but there's no path forward on climate that doesn't involve both.
- acidburnNSA 4y ago
  Why electrify all the things instead of decarbonize all the things? Lots of places use zero carbon nuclear district heating to take advantage of the hot water for building heat. It can be pumped 100 km from the plant as it is at Beznau. This makes nuclear more cost effective as well since you're using a valuable product (heat) that is otherwise wasted.
  - twobitshifter 4y ago
    The idea of nuclear power plants in the US near residential communities is a non-starter. Solar thermal or geothermal might be an option, but I believe heat pumps outperform those options on cost.
    - acidburnNSA 4y ago
      How is it a non-starter? Nuclear plants are low-carbon and extremely safe [1]. 100 km is a long way. There are millions of people in the USA living within 100 km of a nuclear plant. Showing people the numbers on nuclear isn't that hard. [1] https://ourworldindata.org/safest-sources-of-energy https://ourworldindata.org/safest-sources-of-energy

londons_explore 4y ago

I worry about the 'futureproofness' of heat pumps. Specifically, heat pumps use more energy on cold days. They use a massive amount more energy on the coldest days. Today, if you use double the electricity, it costs double the money. Thats affordable as long as it happens rarely. But, with lots of people getting EV's and heat pumps, and the generation mix getting more wind and solar, I forsee energy companies forcing customers onto dynamic pricing plans. Ie. the price adjusts every hour of the day. Now when it's cold, and everyone else is trying to use extra power for their EV's and heat pumps, the price will go way up. So now, instead of using double the power and paying double, you'll use double but pay 50x. Suddenly the economics of a heat pump don't look so attractive when you realise you paid $300 on one cold night... Dual heat sources solve this (I doubt gas will ever have dynamic hourly pricing).

Scoundreller 4y ago
Retrofit market is still huge, especially in Maine where people mostly Don’t have natural gas connections and therefore don’t have a monthly standby charge for that. When you already have a Woodstove, pellet stove, oil heat or propane heat for the cold snaps, yeah, the economics really pushes in favour there.
mkozlows 4y ago
Whether electric companies have that kind of pricing isn't a pure economics question, it's a question of what regulators will alow, and I'm pretty skeptical that regulators would allow that. But "how does the grid handle spikes in demand" is the really interesting question there, and why more transmission lines (to smooth out supply/demand geographically) and reliable sources of "firm" power are important. Energy storage at scale is potentially really important here, too (and one of the reasons why home batteries are more important to the grid in some ways than home solar).
- coryrc 4y ago
  It's not about regulators, it's that you need something rarely, but it's capital costs aren't less than something you need often, so it's going to be really expensive for the short time you need it. Even if you spread the cost out over the year, consumers are paying it one way or another. Our only plan for seasonal change in production and demand is to over-build gas turbines.

rsynnott 4y ago

I find all this fear mongering about heatpumps in the US currently to be a little odd, because they've been popular in some cold countries in Europe for some time. If there was going to be a problem, there would already have been a problem.

throwaway894345 4y ago
Does Europe have cold countries? According to some quick Googling, the average winter temperature in Norway is still warmer than in Iowa (a not-particularly-cold state). (FWIW I think heat pumps are interesting, I drive an electric car, etc--I'm not speaking from some reflexively anti-electrification ideological position)
- rsynnott 4y ago
  Northern Scandinavia gets pretty cold. Various parts of Europe also have exceptional extremely cold weather; the average isn't _really_ what you want to think about when it comes to heating systems (well, it matters, in that it's relevant to the cost structure, but you really want your system to be able to deal with the reasonable edge-case weather).
  - throwaway894345 4y ago
    Yeah, it's a crude metric for sure, but we have to make sure we're making a good comparison before claiming "If there was going to be a problem, there would already have been a problem." Notably, some Googling indicates that heat pumps aren't effective below -13F which can be the high temperature in Iowa (never mind colder states) for week on end. Are heat pumps common in parts of Scandinavia that get this cold (or colder)?
- magicalhippo 4y ago
  From what I can see Des Moines[1] and Oslo[2] are fairly comparable, and here in Oslo it's quite common to have air to air heat pumps. Mind you, Oslo is quite south in Norway, it's much colder further north. [1]: https://www.weather.gov/wrh/climate?wfo=dmx https://www.weather.gov/wrh/climate?wfo=dmx (annual) [2]: https://seklima.met.no/months/max(air_temperature https://seklima.met.no/months/max(air_temperature P1M),mean(air_temperature P1M),min(air_temperature P1M)/recurring_period/SN18700/nb/2003-01-01T00:00:00+01:00;2023-01-31T23:59:59+01:00

AbrahamParangi 4y ago

Heat pumps are obviously great but the enthusiasm for regulating Green technology into housing design seems to me to trade the interests of the poor for the interests of the upper middle class.

anovikov 4y ago
Short-term interests of the poor, that is. On the next round, when non-renewable energy will become really scarce, poor won't be able to heat their homes at all without "green technology".
- AbrahamParangi 4y ago
  Easy to say “this is what you should want” when it’s really what I want.
  - jobs_throwaway 4y ago
    what do you mean by that

beamgirl 4y ago

My dad is a retired heat and power engineer up in Maine (20something years at a paper mill). We probably spent half of Christmas talking about his new minisplit. He has been tracking his electricity bill and heating oil bills in spreadsheets for years. He still has the old oil boiler in place for emergencies, but as far as I know he hasn't had to use it yet this year. He said he wanted more data before he made a definitive statement about the savings, but initial results seemed pretty promising even in the cold spells we've had

zdragnar 4y ago
To be fair, pretty much anything would save money over heating oil, including just burning money.
- sbradford26 4y ago
  I know it is sarcastic but there is a website where you can calculate how much it would cost to heat with dollar bills. https://coalpail.com/fuel-comparison-calculator-home-heating https://coalpail.com/fuel-comparison-calculator-home-heating
  - beamgirl 4y ago
    Coalpail is a really handy site. They've got all the hookups on the cheap coal distributors. The guy I buy from isn't listed, you just call him and ask for an appointment to meet him at his coal shed.
  - zdragnar 4y ago
    Where on earth did they get $250 for a cord of wood? Unless you're buying them 10-13 logger's cords at a time, then cutting and splitting it yourself, a cord of oak around where I live (which is not at all far from oak trees) is in the $450-550 range. You can maybe push it down to $300/cord if you know a guy, but then you're not getting properly seasoned stuff, you're getting stuff recently cut from a dead tree left standing for a few years.

overreg 4y ago

Are these air to air systems? Retrofitting heat pumps for air to water central heating, as is normally done in the UK, is really expensive and rarely makes economic sense for an individual household.

twobitshifter 4y ago
They are air to air. The hydronic heat pumps are not common in the US AFAIK, but I’d love to hear if anyone has found an affordable solution.
- hedgehog 4y ago
  They are less common but available, I have just recently been looking at options that will do combined hydronic heat and hot water for the taps. The hardware isn't too expensive but the labor for that kind of install can be a lot (highest number I got estimated was $60k).
stanleydrew 4y ago
These seem to be mostly so-called "mini-splits" which are air to air ductless systems.
fundad 4y ago
Yes

sharemywin 4y ago

Even if we had discounts at the pump to subsidize things I wish different costs like environmental costs were added to the price so people could at least see the the true price to make decisions

hedora 4y ago

What a fitting anti-electrification PR campaign for the 120th anniversary of Edison intentionally (allegedly, and perhaps fraudulently) electrocuting a homicidal elephant to teach us of the dangers of alternating current! https://science.howstuffworks.com/innovation/science-questions/why-did-thomas-edison-electrocute-elephant.htm https://science.howstuffworks.com/innovation/science-questio... Anyway kids, remember, every time your heat pump spins up, Dumbo’s mom dies. Now, drink up the fuel oil the nice man in the red suit delivered last Christmas. It’ll put hair on your chest. More info (warning: graphic images): https://en.m.wikipedia.org/wiki/Electrocuting_an_Elephant https://en.m.wikipedia.org/wiki/Electrocuting_an_Elephant

1234letshaveatw 4y ago
Edison was advocating Direct Current, not fuel oil?

suls 4y ago

What’s the cost of a kWh in Maine? The newer houses here in Japan tend to be all-electric (water, stove, AC) and the current prices (~¥40/kWh) make a lot wish for kerosene heaters of the past decades.

flyingfences 4y ago
(40 JPY is .304 USD today) Most of Maine is paying .264 USD/kWh this winter.

losvedir 4y ago

I know heat pumps are all the rage on HN these days, but I looked into them for myself in Indiana, and they don't seem to make financial sense at all, unfortunately. My utility, NIPSCO, charges $0.25699/therm for gas. There are 29.3 kWh of energy in 1 therm of gas, and my furnace is 95% efficient, so this works out to an electric equivalent of $0.009/kWh. That's more than an order of magnitude cheaper than the electric equivalent! Even a really efficient heat pump isn't going to be able to overcome that. Am I doing the calculations wrong, or are my utility rates way out of whack, or are heat pumps just generally more expensive for everyone to run, but they still think it's worth it? I'm trying to understand how my situation is so different, because I was pretty excited about swapping out my gas furnace for a heat pump and went down that rabbit hole quite a ways before realizing my specific utility rates don't seem to make sense for it.

loudmax 4y ago
Heat pumps don't just convert electricity into heat. They work like an air conditioner in reverse, concentrating heat from outside into your house. Compared to a traditional heating element they're over 100% efficient.
timmg 4y ago
The thing with heat pumps is that they don't create heat, they pump it. So they are "more than 100% efficient" (meaning: they move more heat than what the equivalent energy is).
trynewideas 4y ago
> My utility, NIPSCO, charges $0.25699/therm for gas Well, there you go. Natural gas in Maine is $1.95 to $3.58 per therm. https://www.maine.gov/energy/heating-fuel-prices https://www.maine.gov/energy/heating-fuel-prices
strgcmc 4y ago
I don't understand how you can compare the price of gas (which you convert into an equivalent $/kWh price, no issues so far), with the price of electricity, without trying to account for how long or how often either heating system has to run for... it's almost certainly not the same amount of time. For example, let's imagine an experiment where 2 heating systems are tasked with doing the same thing -- let's say, to keep a 2000 sq ft home at an even 70F degrees, when the outside air temperature is 0F while the ground temp is whatever-it-is: - How much gas would the gas system consume, over how many hours, to maintain that 70F temp? Maybe it uses X1 amount of gas, over Y1 hours, for Z1 price of gas, so you can multiply that out. - How much electricity would a heat pump consume, over how many hours? Maybe it uses X2 amount of electricity, over Y2 hours, for Z2 price. You're only comparing Z1 and Z2, how could that possibly tell you the whole story? Heat pumps can be >100% efficient (I've seen claims of up to 300% efficiency in ideal conditions), while gas maxes out at about 95%, so I don't know why you wouldn't try to measure/estimate the X and Y variables too, and why you'd only focus on the Z.

jakedata 4y ago

Heat pump electrical usage does not go up as the temperature drops. In fact the actual heat pump itself uses less electricity because the compressor needs to slow down in order to scavenge the outdoor heat needed to vaporize the refrigerant. What causes a spike in electrical usage is the backup resistive heat source that kicks in when the compressor cannot satisfy the demand for heat. Installing a heat pump that is engineered and properly sized for extreme cold will prevent this issue. My heat pump does not have a backup resistive heater and I can watch the compressor cycle in realtime on my Sense Home Energy Monitor. The pattern is quite obvious once you understand what you are looking at. -edit- power consumption tracks the heat load in normal temp ranges, I am referring to the backup heat source turning on during extreme cold.

thehappypm 4y ago
Incorrect, efficiency drops as the temperature differential grows. This is a basic law of thermodynamics, since you can extract energy from a temperature difference, it must require energy to create one.
- jakedata 4y ago
  Absolutely true - efficiency drops. Electrical consumption also drops if your heat exchanger can't scavenge enough heat from the air to vaporize your refrigerant. The compressor must slow down. Or as I pointed out - you can activate a backup heat source which causes a huge spike in electrical usage. Probably better than freezing however.
  - thehappypm 4y ago
    Most heat pumps don’t have a backup built in anymore, though. I have 2 (LG and Mitsubishi) and neither has a resistive backup built in.
    - timbit42 4y ago
      My heat pump is 11 years old and doesn't have a resistive heater. I thought resistive heaters were a new thing. Many people in the Northern US and Canada need some kind of backup and a resistive heater in the heat pump would be a selling point for many.

efitz 4y ago

What gets me is why so many localities are pushing or requiring electrification when the grid in many areas is already overloaded. For goodness sake California has fairly regular rolling blackouts and yet many cities are banning gas hookups. The right energy tech, IMO, is “all of them”.

bryanlarsen 4y ago
California's grid falls down in the summer time during peak air conditioner use. It has spare capacity in the winter time.

mytwocentsworth 4y ago

Related heatpump info for the DIY crowd: Homemade Heat Pump Manifesto (2009) [1]. Although factors such as extreme cold-weather performance will be compromised, the lower cash outlay confers considerable appeal to this approach. > My initial goal was to make available the knowledge and possibility that anybody with a few tools and gumption could convert discarded air conditioners, and dehumidifiers into very high efficiency heat sources, or cooling sources. Through the years, we have received reports of success from many people, living in many states, and countries. [1] https://news.ycombinator.com/item?id=32959850 https://news.ycombinator.com/item?id=32959850

subpixel 4y ago

Electricity prices have jumped about 50% this year in Maine, so the calculations many used when installing heat pumps are way off. https://www.pressherald.com/2022/11/16/power-supply-rates-for-most-cmp-customers-to-rise-again-in-2023/ https://www.pressherald.com/2022/11/16/power-supply-rates-fo...

flyingfences 4y ago
https://archive.is/VnYRJ https://archive.is/VnYRJ

upsidesinclude 4y ago

Any engineers feel like running the heat calcs on whether it's actually more beneficial to have the heat exchanger in a small enclosed space heated by the wood stove? Im curious if the efficiency of the heat pump would allow for minimally heating the condenser to keep within the operating range. That space might only be heated to +10°F, but would allow for the heat pump to operate normally.

giardini 4y ago

The bare insulation in the roof shown in the photograph gives me the heebie-jeebies.