ᐅ Basement floor insulation – Heating cost savings

Hello,

I am building a bungalow of 127 sqm (1,367 sq ft) with gas heating, solar panels, and underfloor heating.

The plan is to have a 20 cm (8 inch) reinforced concrete slab with standard insulation beneath the screed.

An additional perimeter insulation below the foundation slab would cost around 2,500 euros.

The architect calculated an extra annual energy cost of 40 euros without this additional insulation, based on current energy prices.

What are your experiences with this? How much heat is actually lost in reality? Maybe some of you have practical insights?

Thank you all in advance.

How is anyone supposed to have experience? No one builds the exact same house twice, except for the foundation insulation.

If your architect says that, why don’t you trust him? It sounds very reasonable... a good architect.

Are you building without a basement? How thick will the insulation be?

Based on the numbers, the answer would be clear to me.

Sebastian79 schrieb:
How can anyone have practical experience? No one has built the exact same house twice, except for the floor insulation.

If your architect says that, why don’t you trust him? It sounds very reasonable... good architect

Because the costs were stated independently of the energy carrier or source, and otherwise he didn’t make a particularly good impression.

I’m actually only interested in whether anyone has installed underfloor heating without insulation beneath the slab in a new build, and if the energy costs remain manageable during winter or if there’s a significantly higher consumption. I’m aware that no direct 1:1 comparison is possible here...

I have no experience yet either. And you probably won’t really notice it—especially since you don’t have any point of comparison.

And the costs definitely won’t skyrocket.

sirhc schrieb:
Are you building without a basement? How thick will the insulation be?

Based on the figures, the answer is clear to me.

Exactly, without a basement. The concrete slab edge will be built up with sand-lime bricks, with perimeter insulation around the slab edge. I will find out on Friday which insulation will be installed under the screed.