4 ms·

That reasoning isn't enough on its own, because on the clients' end, electric heat pumps can be more efficient than direct steam heating. Actually their "effici

That reasoning isn't enough on its own, because on the clients' end, electric heat pumps can be more efficient than direct steam heating. Actually their "efficiency" is far above 100%, https://en.wikipedia.org/wiki/Coefficient_of_performance https://en.wikipedia.org/wiki/Coefficient_of_performance

virtue3 2y ago
And their efficiency plummets starting at 40F and below.
- nebolo 2y ago
  The efficiency of modern cold-climate heat pumps plummets to 200-300% at 40F and perhaps 175% at 5F.
  - Brian_K_White 2y ago
    But 5f is still high. This is actually terrible and supports their point. Heat pumps are not sized as if they were running at a mere 100% or less, they are sized for the btus they normally produce, and aim to run close to 100% of the time, meaning they will be too small and not be able to do the job when they drop below 200-300% efficiency, unless they are grossly oversized. That leads to short cycles which makes condensation and moisture in the summer and wear and tear all year and less electrical efficiency because starting a pump and blower costs more than running it. Current inverter types that can run slow do allow them to be oversized but it's still not great. Those are more expensive and have more failure points in electronics too.
  - whatevaa 2y ago
    So at -20 and below they are basically very, very expensive resistive heaters. Good for medium climates, bad further north. Also either need very expensive oversizing or backup heat sources to compensate reduced heat output, even if you get occasional cold spikes. Unfortunately nothing in life is as simple as it first seems.
    - jacobaul 2y ago
      Here is a great Technology Connections video which lays out why the sizing issue might not be as bad as you're thinking. The gist is that many people are steered away from heat pumps (or sold very expensive oversized units) by outdated industry thinking which vastly overestimates load calculations. I won't try to make his case here, but he is pretty convincing that a reasonably sized heat pump system can be sufficient even in very cold climates (by US standards). https://youtu.be/DTsQjiPlksA https://youtu.be/DTsQjiPlksA
      - whatevaa 2y ago
        It's all theoretical. In real life, retrofitting heat pumps into exisinting homes is a bit different, as those homes are neither made for air heat sources (at least in my region), nor they are insullated well. You might say, dough, insulate it, but it is easier said than done, as a lot of those old homes relied on their leakage for ventilation, not to mention that is very expensive investment (much more expensive than the heat pump itself). I would reccommend keeping backup heat source when installing heat pumps into older homes. A simple wood stove, used during cold spikes, could be enough. My country has subsidies for heat pump installations into older homes and it had requirement to get rid of chimneys to get that. After the whole europe energy crisis thing, this requirement is gone now. Turns out having alternatives is a good thing :)
        eldaisfish 2y ago
        I live in Canada in an older home with terrible insulation. Out two tonne heat pump works just fine even at -25C this past winter. We still have a natural gas furnace but our gas usage is down 65% despite this winter being colder than last year’s. Tell me again how heat pumps don’t work in colder climates?
        bluGill 2y ago
        This is why I opposed historical designations. Most old buildings are obsolete and need to be destroyed. There are only a tiny number of buildings that are really historic, sure save them, but the vast majority are just old and need to be knocked down for something better. If it isn't taught in history class then it isn't historic. It is easy to see the loss of something old. However the opportunity cost from not building new is something that is very hard to get people to understand.
- brnt 2y ago
  1990s called, they want their efficiency back ;) Sure, you can still find good weather heat pump that crap their pants near or under freezing. However, the majority sold here in Europe still stay well of 200% down to -15C, some even -25C.
- yencabulator 2y ago
  75% of rated capacity at -22 F (-30 C), over here.
smadge 2y ago
“Fifth generation” district heating uses heat pumps to extract heat from a network of lukewarm water.
- m4rtink 2y ago
  Yep and IIRC you can even dump waste heat back to the loop at what would normally be just consumers - eq. to cool a hockey stadium or for a big building AC system.

virtue3 2y ago

And their efficiency plummets starting at 40F and below.

nebolo 2y ago
The efficiency of modern cold-climate heat pumps plummets to 200-300% at 40F and perhaps 175% at 5F.
- Brian_K_White 2y ago
  But 5f is still high. This is actually terrible and supports their point. Heat pumps are not sized as if they were running at a mere 100% or less, they are sized for the btus they normally produce, and aim to run close to 100% of the time, meaning they will be too small and not be able to do the job when they drop below 200-300% efficiency, unless they are grossly oversized. That leads to short cycles which makes condensation and moisture in the summer and wear and tear all year and less electrical efficiency because starting a pump and blower costs more than running it. Current inverter types that can run slow do allow them to be oversized but it's still not great. Those are more expensive and have more failure points in electronics too.
- whatevaa 2y ago
  So at -20 and below they are basically very, very expensive resistive heaters. Good for medium climates, bad further north. Also either need very expensive oversizing or backup heat sources to compensate reduced heat output, even if you get occasional cold spikes. Unfortunately nothing in life is as simple as it first seems.
  - jacobaul 2y ago
    Here is a great Technology Connections video which lays out why the sizing issue might not be as bad as you're thinking. The gist is that many people are steered away from heat pumps (or sold very expensive oversized units) by outdated industry thinking which vastly overestimates load calculations. I won't try to make his case here, but he is pretty convincing that a reasonably sized heat pump system can be sufficient even in very cold climates (by US standards). https://youtu.be/DTsQjiPlksA https://youtu.be/DTsQjiPlksA
    - whatevaa 2y ago
      It's all theoretical. In real life, retrofitting heat pumps into exisinting homes is a bit different, as those homes are neither made for air heat sources (at least in my region), nor they are insullated well. You might say, dough, insulate it, but it is easier said than done, as a lot of those old homes relied on their leakage for ventilation, not to mention that is very expensive investment (much more expensive than the heat pump itself). I would reccommend keeping backup heat source when installing heat pumps into older homes. A simple wood stove, used during cold spikes, could be enough. My country has subsidies for heat pump installations into older homes and it had requirement to get rid of chimneys to get that. After the whole europe energy crisis thing, this requirement is gone now. Turns out having alternatives is a good thing :)
      - eldaisfish 2y ago
        I live in Canada in an older home with terrible insulation. Out two tonne heat pump works just fine even at -25C this past winter. We still have a natural gas furnace but our gas usage is down 65% despite this winter being colder than last year’s. Tell me again how heat pumps don’t work in colder climates?
      - bluGill 2y ago
        This is why I opposed historical designations. Most old buildings are obsolete and need to be destroyed. There are only a tiny number of buildings that are really historic, sure save them, but the vast majority are just old and need to be knocked down for something better. If it isn't taught in history class then it isn't historic. It is easy to see the loss of something old. However the opportunity cost from not building new is something that is very hard to get people to understand.
brnt 2y ago
1990s called, they want their efficiency back ;) Sure, you can still find good weather heat pump that crap their pants near or under freezing. However, the majority sold here in Europe still stay well of 200% down to -15C, some even -25C.
yencabulator 2y ago
75% of rated capacity at -22 F (-30 C), over here.

smadge 2y ago

“Fifth generation” district heating uses heat pumps to extract heat from a network of lukewarm water.

m4rtink 2y ago
Yep and IIRC you can even dump waste heat back to the loop at what would normally be just consumers - eq. to cool a hockey stadium or for a big building AC system.