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> There also isn’t a low temperature heat pump solution that works for radiators. There are. Here's one [1] that works down to -26 Celsius (47 F below freezin

> There also isn’t a low temperature heat pump solution that works for radiators. There are. Here's one [1] that works down to -26 Celsius (47 F below freezing!!) and connects to radiators. In practice it will also work below -26 C, since multi-zone pumps can use other rooms to balance out reliance on the external radiator. It's also crazy efficient: at -13 C/5 F it still moves 12078.98 BTUs of heat per kWh of electricity consumed. At 10.42 cents/kWh that's nearly half the price of natural gas. [1]: https://www.fujitsu-general.com/us/products/vrf/j4/aou60rlavm4.html https://www.fujitsu-general.com/us/products/vrf/j4/aou60rlav...

sixstringtheory 4y ago
-26°C is only -14.8°F, but your point stands, they’re getting better at lower temps.
- hwillis 4y ago
  15 F is 47 F below freezing, which is what I meant to say.
denimnerd42 4y ago
-40C is -40F so your conversion isn't right. We spend most of the winter night below 0F so these heat pump options don't look viable. Not to mention we have no where outside to put this thing it won't be covered in snow. Resistive heat is the only thing that seems viable and that's crazy expensive.
- hwillis 4y ago
  47 F below freezing, not below zero. > We spend most of the winter night below 0F so these heat pump options don't look viable. The heat pump does not stop working or turn off at -15 F. It reaches COP=1. It still warms your house, just not more efficiently than resistive heat. Your house also stores warmth, and if insulated well it will not become cold during whatever period the temperature drops below -25 F. Failing both of those, just keep whatever heating you have right now. That's all you have to do. > Not to mention we have no where outside to put this thing it won't be covered in snow. You do. Put it on a stand. Hang it on a wall if you like. Put it on the roof. It does not need to sit on the ground.
  - deleted 4y ago
    [deleted]
amluto 4y ago
Really? Their catalogue suggests that it can connect to floor mount indoor units that replace radiators. That’s not quite the same thing. As I understand it, for two-pipe (hydronic) radiators, and air-to-water heat pump can operate them. Chiltrix makes one for residential use. Other vendors seem to mostly offer this feature for commercial use. For single pipe steam radiators, you need steam. I’ve never seen one of these systems that worked well, but if someone doesn’t want to replace it outright, any heat pump option will need very high output temperature.
- jabl 4y ago
  IIRC there are heat pumps that provide up to 180C steam, but that's for industrial usage, I haven't seen anything like that for residential usage.
- hwillis 4y ago
  So you'd buy a heat pump, but you don't want to buy the radiators for the heat pump? Why? If you like the look of steam radiators (and all of the burn/leak hazards that come with that), just keep the radiators and lose the steam. The difficulty in replacing things like steam radiators is that installing ducts in an existing house is too expensive and difficult. Multi-zone heat pumps let you avoid that.
  - Spooky23 4y ago
    They are more limited right now although newer models have emerged in the last 3 years. The split systems are a viable solution, but are aesthetically pretty awful. The point is that these types of retrofits are expensive and the tech is new. Now, we should be pushing lots of carrots to encourage installation. Take out the sticks later as the gas infrastructure starts to become obsolete. To me the mandate is the problem. In my case, I’ll gladly buy as soon as it’s viable for me. But I have the means to think that way.
  - amluto 4y ago
    One might be very willing to replace a boiler in the basement but much less willing to install new pipes in the walls.
denimnerd42 4y ago
You've got to put this thing outside though right? So how do I keep it clear from snow? And not just a little snow. Snow that comes in 1 foot lifts day after day. I would need quite a big shelter to prevent snow drifts and give it the room it needs.
- mixmastamyk 4y ago
  Winter awnings are a thing. Probably want it raised off the ground somewhat as well.
  - denimnerd42 4y ago
    Sounds like a maintenance/snow removal nightmare compared to a natural gas boiler for hydronic heat that just works. I'd need space for a huge natural gas backup generator too.
    - mixmastamyk 4y ago
      If you're determined to fail, you will. Believe it is called learned helplessness.
      - denimnerd42 4y ago
        ? that's uncalled for. It's called the right tool for the job and not introducing the fucking environment into my heating system more than necessary at 200-300" of snow per year and regular -20F or -30F nights. I would love to use a hyper efficient heat pump solution so I'm asking the questions here.
        mixmastamyk 4y ago
        Wasn't meant to be an insult, but I suppose it is a blunt fact that could be unwelcome. If you look for solutions, you'll eventually find them (within reason). The opposite holds as well.
- 4y ago

sixstringtheory 4y ago

-26°C is only -14.8°F, but your point stands, they’re getting better at lower temps.

hwillis 4y ago
15 F is 47 F below freezing, which is what I meant to say.

denimnerd42 4y ago

-40C is -40F so your conversion isn't right. We spend most of the winter night below 0F so these heat pump options don't look viable. Not to mention we have no where outside to put this thing it won't be covered in snow. Resistive heat is the only thing that seems viable and that's crazy expensive.

hwillis 4y ago
47 F below freezing, not below zero. > We spend most of the winter night below 0F so these heat pump options don't look viable. The heat pump does not stop working or turn off at -15 F. It reaches COP=1. It still warms your house, just not more efficiently than resistive heat. Your house also stores warmth, and if insulated well it will not become cold during whatever period the temperature drops below -25 F. Failing both of those, just keep whatever heating you have right now. That's all you have to do. > Not to mention we have no where outside to put this thing it won't be covered in snow. You do. Put it on a stand. Hang it on a wall if you like. Put it on the roof. It does not need to sit on the ground.
- deleted 4y ago
  [deleted]

amluto 4y ago

Really? Their catalogue suggests that it can connect to floor mount indoor units that replace radiators. That’s not quite the same thing. As I understand it, for two-pipe (hydronic) radiators, and air-to-water heat pump can operate them. Chiltrix makes one for residential use. Other vendors seem to mostly offer this feature for commercial use. For single pipe steam radiators, you need steam. I’ve never seen one of these systems that worked well, but if someone doesn’t want to replace it outright, any heat pump option will need very high output temperature.

jabl 4y ago
IIRC there are heat pumps that provide up to 180C steam, but that's for industrial usage, I haven't seen anything like that for residential usage.
hwillis 4y ago
So you'd buy a heat pump, but you don't want to buy the radiators for the heat pump? Why? If you like the look of steam radiators (and all of the burn/leak hazards that come with that), just keep the radiators and lose the steam. The difficulty in replacing things like steam radiators is that installing ducts in an existing house is too expensive and difficult. Multi-zone heat pumps let you avoid that.
- Spooky23 4y ago
  They are more limited right now although newer models have emerged in the last 3 years. The split systems are a viable solution, but are aesthetically pretty awful. The point is that these types of retrofits are expensive and the tech is new. Now, we should be pushing lots of carrots to encourage installation. Take out the sticks later as the gas infrastructure starts to become obsolete. To me the mandate is the problem. In my case, I’ll gladly buy as soon as it’s viable for me. But I have the means to think that way.
- amluto 4y ago
  One might be very willing to replace a boiler in the basement but much less willing to install new pipes in the walls.

denimnerd42 4y ago

You've got to put this thing outside though right? So how do I keep it clear from snow? And not just a little snow. Snow that comes in 1 foot lifts day after day. I would need quite a big shelter to prevent snow drifts and give it the room it needs.

mixmastamyk 4y ago
Winter awnings are a thing. Probably want it raised off the ground somewhat as well.
- denimnerd42 4y ago
  Sounds like a maintenance/snow removal nightmare compared to a natural gas boiler for hydronic heat that just works. I'd need space for a huge natural gas backup generator too.
  - mixmastamyk 4y ago
    If you're determined to fail, you will. Believe it is called learned helplessness.
    - denimnerd42 4y ago
      ? that's uncalled for. It's called the right tool for the job and not introducing the fucking environment into my heating system more than necessary at 200-300" of snow per year and regular -20F or -30F nights. I would love to use a hyper efficient heat pump solution so I'm asking the questions here.
      - mixmastamyk 4y ago
        Wasn't meant to be an insult, but I suppose it is a blunt fact that could be unwelcome. If you look for solutions, you'll eventually find them (within reason). The opposite holds as well.
4y ago