Adding underfloor heating, crawl space

[Lovikavanten]

Hi! We are planning to replace the radiators with underfloor heating. The house was built in 83, is heated with geothermal energy, and we are going to lay wooden floors (click).

Now we have two proposals, one is to lay regular underfloor heating on top of the existing joists, and for about 150 000 SEK more, we can choose EPS concrete and float for more even heat distribution and better insulation. It sounds very nice with even, comfortable heat, but we have low operating costs and are planning to remodel the entire house, so the question is whether it is worth it...

Of course, one doesn't fully know how the existing insulation looks, maybe it's bad and needs to be replaced, but that probably doesn't cost more than about 20,000 (just guessing).

Does anyone have smart input or opinions for or against?

 

[klaskarlsson]

Hi! We're going to replace radiators with underfloor heating. The house was built in '83, is heated with geothermal energy, and we're going to install wooden floors (click).

We received two proposals: one to install standard underfloor heating on top of the existing joists, and for about 150,000 SEK more, we could choose EPS concrete and float it to achieve more even heating and better insulation. It sounds very nice to have even, comfortable heat, but we have low operating costs and are planning to renovate the entire house, so the question is if it's worth it...

Of course, one can't entirely know what the existing insulation looks like, maybe it's bad and needs to be replaced, but that probably doesn't cost more than around 20,000 (just guessing).

Does anyone have any smart input or opinions for or against?

How much difference does EPS concrete make in terms of insulation?
You lose a little less heat overall if it's better insulated, but I'm not sure the "evenness" makes much difference though.

 

[Lovikavanten]

How much difference is there in terms of insulation with EPS concrete?
You lose slightly less heat overall if it's better insulated, but I'm not sure if the "evenness" makes much of a difference.

What he emphasized a bit was that with a heavier subfloor, i.e., the top layer floats, it keeps the heat, and you can further reduce the supply temperature. But as far as I can see, mineral wool is better insulating than EPS-cement (0.037 against 0.08), so the question is if we should spend the 150k kr on something more fun 😄

 

[jhall]

What volume of EPS are we talking about? I have poured EPS in our basement and when I checked prices, it was the pump truck that made the cost rise, so I mixed it myself. EPS is very forgiving to work with and not particularly expensive.

 

[Lovikavanten]

What volume of EPS are we dealing with? I have poured EPS in our basement and when I checked prices it was the pump truck that made it expensive, so I did it myself. EPS is very forgiving to work with and not particularly expensive.

If I'm thinking correctly, it should be about 40 m² x 0.2 m = 8 m³. We won't be doing it ourselves, and a large part in addition to the pump truck will also be labor hours to build the casting mold from underneath the crawl space.

 

[useless]

For about 150,000 SEK more, we can instead choose EPS concrete and float it for more even heat distribution and better insulation.

EPS insulates only one-third as well as mineral wool. So it definitely won't be better insulated compared to, for example, fiberglass which is also much cheaper.

 

[kashieda]

EPS insulates only a third as well as mineral wool. So it definitely won't be better insulated compared to, for example, fiberglass, which is also much cheaper.

However, mineral wool retains water that leaks in, and then it doesn't insulate at all, and it leads to rot or worse.

Mineral wool is a very bad idea in foundations.

 

[useless]

However, mineral wool retains water that leaks in, and then it does not insulate at all, and it leads to rot or worse.

Mineral wool is a very bad idea in foundations.

It's not about mineral wool in a foundation. It's a floor structure with a crawl space underneath. That is, the most common construction in existing houses today.

 

[Lovikavanten]

EPS insulates only a third as well as mineral wool. So it definitely does not insulate better compared to, for example, glass wool which is also much cheaper.

No, that's what I concluded as well.. we will probably skip EPS and spend that money on something else