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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 peo

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

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