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I think the biggest hurdle to heat pump adoption (at least in North America) is likely to be that it provides an experience that simply isn't as good as a gas f

by Merad 2y ago

I think the biggest hurdle to heat pump adoption (at least in North America) is likely to be that it provides an experience that simply isn't as good as a gas furnace. On a chilly morning the air coming out of the vents just isn't that warm and it may take hours to bring the house up to temp, whereas gas puts out pleasantly warm air immediately and can quickly warm the house even on the coldest days. When it's truly cold (like < 20F) the heat pump will run continuously and struggle to maintain temp. Don't misunderstand, the heat pump is certainly _good enough_, but people typically don't pick the "good enough" experience over the "better" experience when the better option is available and they can afford it. For reference I've lived in NC and TN near the mountains where heat pumps are pretty standard. I imagine we don't get the ultra high efficiency cold weather heat pump units that would be used up north, but they also get much colder temps than us. Several of the houses I've lived in have been recent construction (2008 and 2018), so well insulated and reasonably new & efficient heat pumps. For the last 2 years I've been in a house with gas, and it's just so damned pleasant... I know on paper that heat pump is better, but I really don't want to give up that furnace.

antisthenes 2y ago
> I think the biggest hurdle to heat pump adoption (at least in North America) > When it's truly cold (like < 20F) the heat pump will run continuously and struggle to maintain temp. Luckily, pretty much the entire Western and Eastern Coastal areas, it doesn't actually get that cold on a regular basis, except a few days in the winter. The US is actually in an incredibly advantageous geographical position for at least 60% of households to be on heatpumps, as opposed to, say, Finland/Canada/Russia etc.
- napoleongl 2y ago
  Meanwhile it was estimated that half of Swedish houses were equipped with heat pumps in 2016. That number has certainly not gone down since given the steep rise in electricity costs we’ve had since. Many houses have been converted from horribly inefficient direct electric heating to heat pumps.
Mvandenbergh 2y ago
Part of the problem is that heat pumps aren't really well suited to a use case where you frequently have to bring a house up to temp in the way you're describing. If you have a big overnight set-back and then the heating comes on in the morning, that will require much more heat output than constantly putting out enough heat to maintain temperature. In a well insulated property, the greater efficiency from operating at low output temperatures outweighs the additional heat loss from no / a low overnight set-back. In a poorly insulated property, the optimum set-back is higher and the efficiency at that optimum point is also much lower because the heat pump has to operate at higher temperature in order to ramp up the temperature. I don't know if they are available in North America, but in the UK we have hybrid systems available that use heat pumps for 80% of the annual heat load and gas for peaking / ramping. OpenTherm gas boilers can be retrofitted to be controlled in this way so you only add the heat pump. An air source heat pump driving a hydronic / radiator system in this climate can serve 80% of the annual load with a unit sized at 55% of peak heat load. Different climates will have slightly different numbers but it shows the power of a hybrid system as you save a lot on HP capex and also maintain redundancy. The advantage of this system is that the failure-mode of an incorrectly sized system is an efficiency penalty rather than not being warm enough, the same as an incorrectly commissioned or sized gas system. (Most gas systems are not optimally sized or configured and are delivering 5% to 10% less efficiency than they could). I don't know if these systems are available in ducted air configuration for the US market though.
Ataraxic 2y ago
It doesn't have to be all heat pump. You can have a backup gas heat for the coldest days, or even resistive heat. I'd bet there are heat pumps that integrate those technologies to ensure a nice experience.
- mholm 2y ago
  When I got a quote to upgrade my resistive heater to a heat pump, the added cost to get a backup resistive heater (with the same capacity as my existing one) was only $500. Seems like as long as you're wired for it, it's very cheap.
SECProto 2y ago
A relative recently upgraded their 120yr old house with heat pumps, and the warmth is so much better than where I currently live (a 40 year old home with a new gas furnace). In my experience you can't generalize about heat source.

by Merad 2y ago

antisthenes 2y ago

> I think the biggest hurdle to heat pump adoption (at least in North America) > When it's truly cold (like < 20F) the heat pump will run continuously and struggle to maintain temp. Luckily, pretty much the entire Western and Eastern Coastal areas, it doesn't actually get that cold on a regular basis, except a few days in the winter. The US is actually in an incredibly advantageous geographical position for at least 60% of households to be on heatpumps, as opposed to, say, Finland/Canada/Russia etc.

napoleongl 2y ago
Meanwhile it was estimated that half of Swedish houses were equipped with heat pumps in 2016. That number has certainly not gone down since given the steep rise in electricity costs we’ve had since. Many houses have been converted from horribly inefficient direct electric heating to heat pumps.

Mvandenbergh 2y ago

Part of the problem is that heat pumps aren't really well suited to a use case where you frequently have to bring a house up to temp in the way you're describing. If you have a big overnight set-back and then the heating comes on in the morning, that will require much more heat output than constantly putting out enough heat to maintain temperature. In a well insulated property, the greater efficiency from operating at low output temperatures outweighs the additional heat loss from no / a low overnight set-back. In a poorly insulated property, the optimum set-back is higher and the efficiency at that optimum point is also much lower because the heat pump has to operate at higher temperature in order to ramp up the temperature. I don't know if they are available in North America, but in the UK we have hybrid systems available that use heat pumps for 80% of the annual heat load and gas for peaking / ramping. OpenTherm gas boilers can be retrofitted to be controlled in this way so you only add the heat pump. An air source heat pump driving a hydronic / radiator system in this climate can serve 80% of the annual load with a unit sized at 55% of peak heat load. Different climates will have slightly different numbers but it shows the power of a hybrid system as you save a lot on HP capex and also maintain redundancy. The advantage of this system is that the failure-mode of an incorrectly sized system is an efficiency penalty rather than not being warm enough, the same as an incorrectly commissioned or sized gas system. (Most gas systems are not optimally sized or configured and are delivering 5% to 10% less efficiency than they could). I don't know if these systems are available in ducted air configuration for the US market though.

Ataraxic 2y ago

It doesn't have to be all heat pump. You can have a backup gas heat for the coldest days, or even resistive heat. I'd bet there are heat pumps that integrate those technologies to ensure a nice experience.

mholm 2y ago
When I got a quote to upgrade my resistive heater to a heat pump, the added cost to get a backup resistive heater (with the same capacity as my existing one) was only $500. Seems like as long as you're wired for it, it's very cheap.

SECProto 2y ago

A relative recently upgraded their 120yr old house with heat pumps, and the warmth is so much better than where I currently live (a 40 year old home with a new gas furnace). In my experience you can't generalize about heat source.