Hello everyone,
We have now been offered the PP4 0.5 (also 36.5 cm (14.4 inches)) instead of the Ytong PP2 0.35 (36.5 cm (14.4 inches)) for better sound insulation. The PP2 has a thermal conductivity (λR) of 0.08 (U-value 0.21), and the PP4 has a thermal conductivity of 0.10 (U-value 0.26). We are tempted by the better sound insulation, but is the heat loss too high? The windows have a Ug value of 0.6. The 2016 energy saving regulation (EnEV) allows a U-value of 0.28. The building will have an air-to-water heat pump + a fireplace + (possibly decentralized ventilation with heat recovery).
What do you think? I couldn’t find anything about this online or here. :-(
We have now been offered the PP4 0.5 (also 36.5 cm (14.4 inches)) instead of the Ytong PP2 0.35 (36.5 cm (14.4 inches)) for better sound insulation. The PP2 has a thermal conductivity (λR) of 0.08 (U-value 0.21), and the PP4 has a thermal conductivity of 0.10 (U-value 0.26). We are tempted by the better sound insulation, but is the heat loss too high? The windows have a Ug value of 0.6. The 2016 energy saving regulation (EnEV) allows a U-value of 0.28. The building will have an air-to-water heat pump + a fireplace + (possibly decentralized ventilation with heat recovery).
What do you think? I couldn’t find anything about this online or here. :-(
For every 1 W/m²K difference in the U-value of a building component, you can expect an energy saving of 70 kWh/m² (surface area, not living area) per year.
When insulating an exterior wall with an area of 100 m² (1,076 sq ft) and reducing the U-value from 1.5 to 0.5 W/m²K, the energy demand decreases by approximately (1.5 - 0.5) * 100 * 70 = 7,000 kWh.
In your example, the U-value changes from 0.26 to 0.21, a difference of 0.05 W/m²K. This results in a saving (assuming 100 m² wall area) of 0.05 * 70 * 100 = 350 kWh per year. At production costs of 10 cents per kWh, that amounts to 35 euros annually...
So it’s probably better to choose warm edge spacers in the windows rather than a thick stone. That likely offers a similar benefit.
When insulating an exterior wall with an area of 100 m² (1,076 sq ft) and reducing the U-value from 1.5 to 0.5 W/m²K, the energy demand decreases by approximately (1.5 - 0.5) * 100 * 70 = 7,000 kWh.
In your example, the U-value changes from 0.26 to 0.21, a difference of 0.05 W/m²K. This results in a saving (assuming 100 m² wall area) of 0.05 * 70 * 100 = 350 kWh per year. At production costs of 10 cents per kWh, that amounts to 35 euros annually...
So it’s probably better to choose warm edge spacers in the windows rather than a thick stone. That likely offers a similar benefit.
Bauherr&-frau9 Oct 2018 17:26Thank you for the invoice! I trust you on this!
Would it be possible to build one row of exterior wall with the PP4 and the other walls with the PP2? The diameter and size remain the same, after all.
Would it be possible to build one row of exterior wall with the PP4 and the other walls with the PP2? The diameter and size remain the same, after all.
Nutshell schrieb:
We used Ytong 36.5 with 0.08. So, a U-value of 0.21. Overall, we have an E55 house. Gas costs 29€ monthly... (of course, no fireplace or other heating support)What do you use for hot water then? 29 euros wouldn’t be possible otherwise.Bookstar schrieb:
How do you heat your hot water then? Otherwise, 29 euros just doesn’t add up.Hot water is mainly heated in the summer by a 5m2 (54 ft2) solar panel system, and in winter usually by other means. Nothing special, just a fairly small collector area.
Bauherr&-Frau schrieb:
Thanks for the calculation! I trust you on that! I think the calculation is somewhat oversimplified and not accurate. You are allowing the U-value to worsen by almost 20%!
In my opinion, a U-value of 0.26 for a new build is very poor and outdated, regardless of whether the energy-saving regulations allow it or not. Soundproofing is often greatly overrated and, as already mentioned, mainly depends on the windows, doors, and so on. If the house is not closer than 30 m (100 feet) to a main road, I wouldn’t worry about soundproofing for the windows.
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