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Heat pumps are reliable even in unfavorable conditions. You will have to invest a lot more electrical energy and you might not be pumping heat as much as just

Heat pumps are reliable even in unfavorable conditions. You will have to invest a lot more electrical energy and you might not be pumping heat as much as just converting electrical energy to heat, but let's not spread the myth that a heat pump will leave you freezing once outside temperatures drops below a certain threshold.

akira2501 3y ago
A heat pump without a resistive heating /option/ will absolutely cease working below a certain temperature. They do, for whatever reason, sell systems that way in some regions.
- KeplerBoy 3y ago
  That's true. Strictly speaking a heat pump doesn't need a resistive heating element, but I've never heard of units not containing that feature. After all it's dirt cheap and enables the reliability, we're discussing here.
- jwr 3y ago
  Perhaps, instead of spreading FUD, it would be worthwhile to mention these "certain temperatures", so that people can make an educated decision of whether it applies to them at all. I'm looking at the datasheet for my Fujitsu system and it is specified to work down to -25°C. Does it lose efficiency when it's cold outside? Sure. But guess what, it's still more effective than resistive heating! I am starting from a SCOP of 4.89.
  - bluGill 3y ago
    The UNIT is specified to work down to -25. The SYSTEM includes the building it is installed in: the local climate, the size and heat loss of the building, how the install was done, and likely some other factors I'm not aware of. If you get less heat from the unit than you lose via other means the system isn't working even though it is delivering heat.
  - akira2501 3y ago
    Perhaps you should have read my comments more carefully. There is absolutely zero "FUD" in any of them. I'm just pointing out facts. The primary fact is that you don't need historical data from heat pump installations to know if they'll be efficient in a given area or not. They're devices. They're engineered. They have specifications. The specifications have implications as to how they will function in a given environment. I'm not here to sell heat pumps or to make you feel good about your past purchases. Are you?
- egberts1 3y ago
  Real question is does it prevent freezing? Like 100%. After all, the human body is quite resilient … above freezing. I am thinking in Nome, Alaska where such heat pump could prove its versatility as an anti-freezing component of living quarters or even maintenance shed.
  - bluGill 3y ago
    Humans can put on clothing and be fine in very cold temperatures. However pipes cannot 1C is a hard minimum safe temperature, once it gets colder than that you risk pipes breaking.
bluGill 3y ago
> let's not spread the myth that a heat pump will leave you freezing once outside temperatures drops below a certain threshold. That is not a myth - I have a heatpump in my house and it will leave me freezing on the coldest days. The system is sized so that it cannot keep my house warm at -5C (the system can deliver heat, but the house will cool down). Worse, it did get below -25C here for a couple days which is as cold as any heat pump will work - I don't know of any house that is insulated so well as to be warm when the outside temperature is below -25C for a few days without some heat - but mine isn't one. A correctly sized heat pump can keep your house warm to -25C, but if the installer doesn't give you a correctly sized system it will not. Most installers don't know how to size heat pumps.

akira2501 3y ago

A heat pump without a resistive heating /option/ will absolutely cease working below a certain temperature. They do, for whatever reason, sell systems that way in some regions.

KeplerBoy 3y ago
That's true. Strictly speaking a heat pump doesn't need a resistive heating element, but I've never heard of units not containing that feature. After all it's dirt cheap and enables the reliability, we're discussing here.
jwr 3y ago
Perhaps, instead of spreading FUD, it would be worthwhile to mention these "certain temperatures", so that people can make an educated decision of whether it applies to them at all. I'm looking at the datasheet for my Fujitsu system and it is specified to work down to -25°C. Does it lose efficiency when it's cold outside? Sure. But guess what, it's still more effective than resistive heating! I am starting from a SCOP of 4.89.
- bluGill 3y ago
  The UNIT is specified to work down to -25. The SYSTEM includes the building it is installed in: the local climate, the size and heat loss of the building, how the install was done, and likely some other factors I'm not aware of. If you get less heat from the unit than you lose via other means the system isn't working even though it is delivering heat.
- akira2501 3y ago
  Perhaps you should have read my comments more carefully. There is absolutely zero "FUD" in any of them. I'm just pointing out facts. The primary fact is that you don't need historical data from heat pump installations to know if they'll be efficient in a given area or not. They're devices. They're engineered. They have specifications. The specifications have implications as to how they will function in a given environment. I'm not here to sell heat pumps or to make you feel good about your past purchases. Are you?
egberts1 3y ago
Real question is does it prevent freezing? Like 100%. After all, the human body is quite resilient … above freezing. I am thinking in Nome, Alaska where such heat pump could prove its versatility as an anti-freezing component of living quarters or even maintenance shed.
- bluGill 3y ago
  Humans can put on clothing and be fine in very cold temperatures. However pipes cannot 1C is a hard minimum safe temperature, once it gets colder than that you risk pipes breaking.

bluGill 3y ago

> let's not spread the myth that a heat pump will leave you freezing once outside temperatures drops below a certain threshold. That is not a myth - I have a heatpump in my house and it will leave me freezing on the coldest days. The system is sized so that it cannot keep my house warm at -5C (the system can deliver heat, but the house will cool down). Worse, it did get below -25C here for a couple days which is as cold as any heat pump will work - I don't know of any house that is insulated so well as to be warm when the outside temperature is below -25C for a few days without some heat - but mine isn't one. A correctly sized heat pump can keep your house warm to -25C, but if the installer doesn't give you a correctly sized system it will not. Most installers don't know how to size heat pumps.