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In Scandinavia we use air to air heat pumps. We generally don't have central heating of any kind so we aren't so tempted to try to shoehorn the heat pump into

In Scandinavia we use air to air heat pumps. We generally don't have central heating of any kind so we aren't so tempted to try to shoehorn the heat pump into a system based on hot water. Air to air is much cheaper and is more efficient because it doesn't need to raise the temperature of the working fluid so much and doesn't require a big fluid to water heat exchanger. I'm having a Toshiba Polar 35 heat pump installed soon. Nominal output 3.5 kW, maximum output 7 kW. The total cost is 28 kNOK, about 2.6 kUSD, 2 kGBP. Should be enough for the whole ground floor of about 80 square metres.

khimaros 3y ago
which refrigerant is used in this?
- kwhitefoot 3y ago
  R-32 [1] "Difluoromethane, also called difluoromethylene, HFC-32 Methylene Fluoride or R-32, " [2] [1] https://www.toshibavarmepumper.no/globalassets/inriver/resources/r106513-datablad-energietikett-toshiba-polar-25.pdf https://www.toshibavarmepumper.no/globalassets/inriver/resou... [2] https://en.wikipedia.org/wiki/Difluoromethane https://en.wikipedia.org/wiki/Difluoromethane
amluto 3y ago
Do mean air-to-refrigerant-to-air or do you literally mean a big box with ducts coming out? The latter is called a “packaged terminal” heat pump in the US, and they haven’t really caught on except in cheap hotels.
- kwhitefoot 3y ago
  It's two parts, the compressor in a box with a big fan on the outside and a box on the wall indoors containing a refrigerant to air heat exchanger and a fan. The two are connected by pipes, typically three or four metres long, containing the refrigerant. So yes, air-to-refrigerant-to-air. But your packaged terminal heat pump is also air-to-refrigerant-to-air. Both are just refrigerators turned inside out. "“Packaged terminal heat pump” means a packaged terminal air conditioner that utilizes reverse cycle refrigeration as its prime heat source, " [1] [1] https://www1.eere.energy.gov/buildings/appliance_standards/standards.aspx?productid=46&action=viewcurrent https://www1.eere.energy.gov/buildings/appliance_standards/s... Most heat pumps installed in dwellings in Norway are capable of cooling the building as well as heating it. This is the one that will be installed in my house (in Norwegian, Google does a good translation job): https://www.toshibavarmepumper.no/varmepumper-luft-luft/toshiba-polar-25/ https://www.toshibavarmepumper.no/varmepumper-luft-luft/tosh...
  - amluto 3y ago
    Wow, that “packaged terminal” page is terrible. They’re a single object, and the refrigerant doesn’t leave the object. Outdoor air flows through part of it, and indoor air flows through another part of it.
balfirevic 3y ago
How do you deal with ventilation? Central unit, or a device per room? Or just opening windows? :-) > Air to air is much cheaper and is more efficient because it doesn't need to raise the temperature of the working fluid so much and doesn't require a big fluid to water heat exchanger It might still be worth it to go with water based system if you're going to have underfloor heating. It requires lower water temperatures, so efficiency hit is not that big compared to air-to-air systems (if there is a hit at all). As a bonus, there are some savings from using the heat pump to heat the hot water for showering and you get the supreme cozyness of warm floors. On the other hand, now you need some other way of cooling in the summer as underfloor system will not work for that.
- kwhitefoot 3y ago
  We rarely need cooling. Average annual temperature is 14°C, maximum last year was 31.5°C in July but the average that month was 17.8°C :-)
  - fragmede 3y ago
    Hopefully that lasts! Where I live it didn't use to get hot, so no one has air conditioning, but for the past three years we've been hit with a week of 32°C/90°f + temperature. Those that can afford it have added air conditioning, but as global climate change kicks in, I'm expecting more extreme weather to become the norm.
    - ChatGTP 3y ago
      I don't want to be rude, but the fact people install are conditioners for 1 week of 32°C is absolutely ridiculous. The majority of the world deal with these temps for months on end without A/C.
      - fragmede 3y ago
        I mean, not everyone went out and bought one, a lot of people just put up with it. But a window AC is roughly $200, which fits within the disposable income budget of the middle class.

khimaros 3y ago

which refrigerant is used in this?

kwhitefoot 3y ago
R-32 [1] "Difluoromethane, also called difluoromethylene, HFC-32 Methylene Fluoride or R-32, " [2] [1] https://www.toshibavarmepumper.no/globalassets/inriver/resources/r106513-datablad-energietikett-toshiba-polar-25.pdf https://www.toshibavarmepumper.no/globalassets/inriver/resou... [2] https://en.wikipedia.org/wiki/Difluoromethane https://en.wikipedia.org/wiki/Difluoromethane

amluto 3y ago

Do mean air-to-refrigerant-to-air or do you literally mean a big box with ducts coming out? The latter is called a “packaged terminal” heat pump in the US, and they haven’t really caught on except in cheap hotels.

kwhitefoot 3y ago
It's two parts, the compressor in a box with a big fan on the outside and a box on the wall indoors containing a refrigerant to air heat exchanger and a fan. The two are connected by pipes, typically three or four metres long, containing the refrigerant. So yes, air-to-refrigerant-to-air. But your packaged terminal heat pump is also air-to-refrigerant-to-air. Both are just refrigerators turned inside out. "“Packaged terminal heat pump” means a packaged terminal air conditioner that utilizes reverse cycle refrigeration as its prime heat source, " [1] [1] https://www1.eere.energy.gov/buildings/appliance_standards/standards.aspx?productid=46&action=viewcurrent https://www1.eere.energy.gov/buildings/appliance_standards/s... Most heat pumps installed in dwellings in Norway are capable of cooling the building as well as heating it. This is the one that will be installed in my house (in Norwegian, Google does a good translation job): https://www.toshibavarmepumper.no/varmepumper-luft-luft/toshiba-polar-25/ https://www.toshibavarmepumper.no/varmepumper-luft-luft/tosh...
- amluto 3y ago
  Wow, that “packaged terminal” page is terrible. They’re a single object, and the refrigerant doesn’t leave the object. Outdoor air flows through part of it, and indoor air flows through another part of it.

balfirevic 3y ago

How do you deal with ventilation? Central unit, or a device per room? Or just opening windows? :-) > Air to air is much cheaper and is more efficient because it doesn't need to raise the temperature of the working fluid so much and doesn't require a big fluid to water heat exchanger It might still be worth it to go with water based system if you're going to have underfloor heating. It requires lower water temperatures, so efficiency hit is not that big compared to air-to-air systems (if there is a hit at all). As a bonus, there are some savings from using the heat pump to heat the hot water for showering and you get the supreme cozyness of warm floors. On the other hand, now you need some other way of cooling in the summer as underfloor system will not work for that.

kwhitefoot 3y ago
We rarely need cooling. Average annual temperature is 14°C, maximum last year was 31.5°C in July but the average that month was 17.8°C :-)
- fragmede 3y ago
  Hopefully that lasts! Where I live it didn't use to get hot, so no one has air conditioning, but for the past three years we've been hit with a week of 32°C/90°f + temperature. Those that can afford it have added air conditioning, but as global climate change kicks in, I'm expecting more extreme weather to become the norm.
  - ChatGTP 3y ago
    I don't want to be rude, but the fact people install are conditioners for 1 week of 32°C is absolutely ridiculous. The majority of the world deal with these temps for months on end without A/C.
    - fragmede 3y ago
      I mean, not everyone went out and bought one, a lot of people just put up with it. But a window AC is roughly $200, which fits within the disposable income budget of the middle class.