Heat pumps: colder countries vs. here

I've recently been improving my home's insulation and finally hit the borderline range where a heat pump might make sense. HLI of 1.997 W/(K·m2) & B1 rating. For what i do personally i'll get a BER accessor to advise, but it's got me struggling with how different the mentality is here with HPs versus in the states.

In the US most everyone has heat pumps that I knew growing up, and my parents had one since the 70s in a home that was built in the 70s and definitely not insulated up to modern standards. The weather there is MUCH MUCH colder than here on any given winter day. My mom still runs the heat pump in that house and the kwh used aren't crazy. (yes i'm going by kwh and not dollars/euros to take the difference in the electricity cost out of it since its substantial, 10.5cents per kwh there). Why do we read such horror stories here about switching to a HP and skyhigh bills when we have warmer temps? Is it just the cost difference or what?

Lumen

I'm guessing that you are underestimating the thermal performance of US housing and overestimating that of Irish housing. AFAIK the US has State inspections during construction to ensure that houses are built to code, so even if standards don't appear that much higher on paper they are probably adhered to much better.

Aren't most US houses timber framed? That might make a difference as cold bridging wouldn't be quite as bad as with concrete.

Also, probably lower external humidity in winter which makes ventilation more effective for a given flow rate.

Lewis_Benson

Are you sure they were heat pumps?

A lot of US houses have AC units, are you sure they weren't what you were thinking of?

monseiur

https://www.boards.ie/discussion/comment/120123049#Comment_120123049

The very same thought crossed my mind. I have been to the US a number of times and to different states and most if not all houses (that I visited or stayed in) had AC but I never heard of heat pumps.

Padre_Pio

Most US houses use gas boilers or furnaces for heating.

Tree

AC is an air to air heat pump. Air to water seems to be more common here with the central heating.

Lewis_Benson

Yes, they rarely use radiators or water etc.

Usually warm air is pumped around the house.

Sleeper12

That's correct and not correct at the same time.

A heat pump is basically a AC unit running in reverse. Many heat pumps are also AC units. Most AC units in homes in the states are AC only.

I would question if OP is missremembering though. Heat pumps are very new to the states. They have been in use in Europe for 50 years or more but extremely rare in the states up to the last few years