The article doesn’t go into it, but a key advantage they have is that heat pumps move heat, rather then trying to generate it. So they can move a lot more heat into your house than would be generated by running the electricity they use through a resistor. This makes them effectively more than 100% efficient (the exact amount depends on temperature) as compared with burning a fuel or resistive heat.

  • thantik@lemmy.world
    link
    fedilink
    English
    arrow-up
    51
    arrow-down
    2
    ·
    8 months ago

    Heat Pumps are just Air Conditioners with a reversing valve. They’re not some special magic.

    • admiralteal@kbin.social
      link
      fedilink
      arrow-up
      27
      ·
      8 months ago

      Increasingly, they also tend to have variable-speed compressors, which offer further efficiency benefits. I think the distinction between A/C and heat pump is useful for consumers.

      • anon6789@lemmy.world
        link
        fedilink
        arrow-up
        16
        ·
        edit-2
        8 months ago

        Just got a Bosch Inverter (variable speed) last summer, and the remainder of the summer and through the winter, my electric usage is down by about 30% over last year’s even though I lowered the thermostat temp in summer and increased it in winter.

        Old system was 20 years old. I was hoping to see some ROI after this surprise expense, and it has exceeded expectation so far.

    • Majoof@aussie.zone
      link
      fedilink
      arrow-up
      13
      arrow-down
      1
      ·
      8 months ago

      Hey, pedant here.

      Air conditioners are heat pumps too, and it’s not the reversing valve that differentiates them. Heat pumps move heat, reversing valve let’s you decide which way to move it.

      • thantik@lemmy.world
        link
        fedilink
        English
        arrow-up
        8
        arrow-down
        1
        ·
        edit-2
        8 months ago

        That’s exactly what I said. Air Conditioners are heat pumps which only pump one way.

        • Majoof@aussie.zone
          link
          fedilink
          arrow-up
          1
          ·
          8 months ago

          No you said heat pumps are air conditioners which is wrong.

          Heat pumps are a technology.

          Some are used as air conditioners, some are used as heaters, some as both. Some are used for heating liquids, some are used for cooling foods. They simply move heat from one location to another, application and reversibility independent.

            • Majoof@aussie.zone
              link
              fedilink
              arrow-up
              1
              ·
              8 months ago

              Nah you’re arse about. It’d be like saying all internal combustion engines are generators.

              Engines just drive things, like cars, generators, lawn mowers etc. They’re a technology for rotating something.

              Heat pumps are just a technology for moving heat.

              Not going to reply any further as unsure at this stage if you’re trolling. Literally just go read the Wikipedia page on heat pumps.

      • okamiueru@lemmy.world
        link
        fedilink
        arrow-up
        1
        ·
        8 months ago

        I like pedants. Is it correct that they’re not necessarily equally efficient in both directions? “Air conditioner” to transfer heat away, vs “heat pump” to transfer heat in? Even though both are heat pumps.

        • SpaceCowboy@lemmy.ca
          link
          fedilink
          arrow-up
          3
          ·
          8 months ago

          Sort of… It’s not so much down to it just not working as good at transferring heat, because the rules of thermodynamics applies… moving heat is moving heat.

          But the devil’s in the details. If it’s below freezing the radiator will frost up and won’t work very good. But that problem is solved by temporarily reversing it to heat of the radiator to melt the frost off of it. These systems do this automatically. Freezing temperature is 273 Kelvin, so there is heat outside even when it’s below freezing so there’s always heat that can be pumped, but there are limits to it.

          You don’t want to be dependent on a heat pump as the only source of heat for your house. But they build electric heaters into many models to handle those conditions. But obviously on really cold days that it needs to supplement the heating with the electric heater it’s not going to be all that efficient, because you’re running an electric heater on those days.

          But most days it’s not going to need to turn on the electric heater, and on your cool spring and fall days it won’t even need to defrost. So when you consider it over the course of a year, the heating cost is way lower.

    • cm0002@lemmy.world
      link
      fedilink
      arrow-up
      5
      ·
      8 months ago

      Can you convert an existing AC system to do both and save money on getting a whole new system installed?

      • PriorityMotif@lemmy.world
        link
        fedilink
        arrow-up
        7
        ·
        8 months ago

        It’s probably not worth it. If you have a system more than 10 years old, then you’re probably going to have to replace the accumulator as well if it uses a different kind of refrigerant. It’s likely cheaper to buy a whole unit and furnace than messing with it.

        • cm0002@lemmy.world
          link
          fedilink
          arrow-up
          2
          ·
          8 months ago

          What about a new system? Had the AC compressor replaced last year but not the gas fired furnace due to cost lol

      • carl_dungeon@lemmy.world
        link
        fedilink
        English
        arrow-up
        3
        ·
        8 months ago

        I believe so but you need a new compressor - the heat exchanger in the house can stay the same I think.

      • OminousOrange@lemmy.ca
        link
        fedilink
        arrow-up
        3
        ·
        8 months ago

        You have a furnace that provides heat, air handler that moves the air, and compressor that forces heat in a certain direction (inside to outside in the case of AC) with coils in the air handler to make use of that (re)moved heat.

        Heat pumps have several features that make them a bit more than backwards AC, like defrost systems, VFDs and often dual-fuel controls. If it snows where you are, you’ll also want it off the ground. So, best to get a new system.

        As another said, you might be able to reuse the coolant lines and coils in the air handler. It might not be a bad idea to keep the furnace for backup when it’s extra cold.