[pgeorgi]

A charitable reading of the parent comment is to focus on "converting". The Nordics tend to have their buildings designed for heat pumps from the start, or converted (and fixed up) a long time ago.

I'm in a house in Germany and got it converted from gas to heat pump a couple of years ago. It took some adaptations to make that work, but on the flip side we obviously blasted lots of heat into the atmosphere before, which we're reigning in now (still work in progress).

So yeah, conversions of houses not built to "heat pump spec" has follow-on efforts and costs that the heat pump hype didn't advertise. I had a rough idea what to expect and that it'll take a while to sort out everything, but if you went into the conversion with the idea that you're just replacing one part with another, you're in for disappointment.

[dghughes]

That reminds me of a house built here in SE Canada in New Brunswick. It's a super efficient home with quadruple glazed windows and walls 1m thick or something like that. The entire house is heated with a unit using the power equivalent to a hair dryer. Just for some perspective it can easily get to -20C or -30C in winter in New Brunswick. It's airtight and very well insulated but yes built that way from the start.

https://www.ecohome.net/guides/1401/new-brunswicks-most-ener...

[chewz]

Exactly what I have meant. New building code is heat-pump friendly but lots of people with older (not old just older) houses had been sold on heat pumps and now pay the price in electricity bills.

[theshrike79]

> The Nordics tend to have their buildings designed for heat pumps from the start

My grandma's house from the 1950's wasn't "designed for heat pumps", neither my other grandma's house from 1940. Neither was my mother in laws from the same period.

You don't need to design anything, you just need a hole in the wall to run the cables.

What does make the houses suited for heat pumps is the fact that Nordic houses are designed to keep the weather out. So when you heat/cool the inside, the house doesn't leak it all outside.

[pgeorgi]

> What does make the houses suited for heat pumps is the fact that Nordic houses are designed to keep the weather out. So when you heat/cool the inside, the house doesn't leak it all outside.

Alright, my bad. Consider "designed" replaced by "suitable".

Houses of a certain era in large parts of Germany (those with only a few days of moderate sub-zero temperatures) tend to have been built with a bit of air leakage capacity to avoid mold. Yes, that's wasteful, but since fossils were (and are) subsidized like crazy, you just heat a bit more and be over with it.

That strategy doesn't work as well when you have less heat to work with.

There are still people who argue that it's unhealthy to live in a properly insulated house ¯\_(ツ)_/¯. I doubt you have a lot of that nonsense in areas that deal with freezing temperatures for months at a time.

[theshrike79]

Yea, the German insistence on "lüften" curing all ailments is legendary :D

[2Gkashmiri]

Do you have online resources I can browse through for conversions?

I have a gas boiler -radiator piping built into the walls and people I talk to say the radiators wont work with heat pump level of temperatures so as in your case the system needs to be converted but how. What are methods and techniques?

[pgeorgi]

Nothing convenient. Bits and pieces here and there, tons of forums, a few videos, a bunch of books, a few specialists who gave good advice.

The inbound temperature into the radiator network took a dive from about 70°C to about 40°C here (I _could_ push the inbound temp to nearly 50°C but by then I'm no better off than with resistive heating), and that's rather obvious when heating the rooms.

The main advice everything came down to was "have a lot of surface that can heat" and from my experience that seems to be quite true.

The house has a bunch of radiators that never ran in the nat-gas days, basically it was overcommitted on heating surface. Now they're pretty well used. Another retrofit option that I had in the back of my head was radiators equipped with a fan to move the air along the radiator surface more quickly (essentially creating "virtual heating surface"), but I didn't need those.

Other than that, warm and cold parts of the house (e.g. basement) are more clearly separated. A FLIR camera module for my phone gave some hints on where heat escapes so that I could focus on the right spots.

When a larger rework of a room is due (and there's a huge mess in any case), that's a chance to look into floor or wall heating there, connected to the same system.

Once that's (mostly) done, I suppose the inbound temperature can be reduced some more, and I expect super-linear electricity savings from that (due to the way the heat pump works).

In terms of costs, it comes out at about the same, although there are more options in electricity availability, and I suspect that pricing there remains more stable than with fossil fuels, so longer-term I expect operating costs to develop beneficially (even if that only means "remains flat"). TCO of the project, I don't know, but I was optimizing for long-term OpEx for various reasons.

By the way: Heating engineers tended to dismiss the project, but the project started before there were any issues with gas supply, so "just use gas" was their go-to solution anyway (for the eco-conscious, they dangled the carrot of "it's H2 ready!", even though it's unlikely that the pipe work will ever support that). Not sure if the attitude of heating engineers changed in the meantime.

In the end it was done by air conditioning technicians, and it can be switched between heating mode using radiators and AC with split system frontends, so this house covers cold winters and hot summers with just one external device (which pleases the historical landmark office)

[2Gkashmiri]

Whats the heating output on your home heat pump? In terms of kW and btu/h?