ᐅ Perimeter insulation 12 or 16 cm extruded polystyrene (XPS)
Created on: 29 Jul 2020 13:50
A
annab377
Hello,
For a single-family house with a concrete wall basement in Baden-Württemberg (average outside temperature around -14°C (7°F) according to the WP map), would you choose 12 cm or 16 cm XPS for perimeter insulation?
What I think about the basement is that it stays pleasantly cool in summer, cooler than the ground and upper floors. If I insulate more, maybe it won’t stay as cool? Or does the 4 cm difference not really matter there? The price difference between 12 and 16 cm is only about 1,500 EUR.
Or is it better to invest the extra 1,500 EUR and then save on heating costs in winter? But the money would have to pay off first through saved heating costs (feels like it would take over 100 years, probably)... hmm
For our KfW 55 house, both 12 and 16 cm XPS perimeter insulation would easily meet the requirements. The thermal transmittance value (U-value) is 0.215.
Regards
For a single-family house with a concrete wall basement in Baden-Württemberg (average outside temperature around -14°C (7°F) according to the WP map), would you choose 12 cm or 16 cm XPS for perimeter insulation?
What I think about the basement is that it stays pleasantly cool in summer, cooler than the ground and upper floors. If I insulate more, maybe it won’t stay as cool? Or does the 4 cm difference not really matter there? The price difference between 12 and 16 cm is only about 1,500 EUR.
Or is it better to invest the extra 1,500 EUR and then save on heating costs in winter? But the money would have to pay off first through saved heating costs (feels like it would take over 100 years, probably)... hmm
For our KfW 55 house, both 12 and 16 cm XPS perimeter insulation would easily meet the requirements. The thermal transmittance value (U-value) is 0.215.
Regards
T_im_Norden schrieb:
I doubt that adding these 4 cm (1.6 inches) is cost-effective; the benefit of additional insulation decreases as thickness increases.Whether it’s cost-effective really depends on the reference point.
Heating costs will certainly be lower with 16 cm (6.3 inches) of XPS insulation. The question is how significant the difference is.
I can only quantify the difference between 12 and 16 cm (4.7 and 6.3 inches) of XPS, and it amounts to about 1,500 EURO. It will probably take several decades to break even. But does the heat pump then run less intensively and therefore somewhat longer? Also, maybe less piping is needed for the underfloor heating? Hmm, I’m quite uncertain.
T
T_im_Norden3 Aug 2020 10:21If you feel more comfortable with it and the money isn’t an issue, go ahead—it won’t do any harm.
Underfloor heating should not be installed sparingly but according to the heating load of the rooms and designed for a low supply temperature.
You can always reduce the heating later, but you can never add extra surface area afterwards.
Underfloor heating should not be installed sparingly but according to the heating load of the rooms and designed for a low supply temperature.
You can always reduce the heating later, but you can never add extra surface area afterwards.
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