ᐅ Single-Family Home Energy Saving Regulation 2016: Is Additional Insulation Recommended by Developers Worthwhile?
Created on: 17 Dec 2015 22:22 ölschlamm
Good evening, dear community,
Our project:
Single-family house according to the new 2016 energy saving regulations
Living area 150m² (1,615 sq ft) DIN
Roof insulation currently 24cm (9.5 inches) mineral wool, U-value 0.19
Exterior wall 17.5cm (7 inches) Poroton + 16cm (6 inches) EPS, U-value 0.19
Builder’s proposal:
Increase roof insulation to 30cm (12 inches), U-value then 0.16, additional cost $2,800
Increase exterior wall insulation to 20cm (8 inches) EPS, U-value then 0.16, additional cost $1,400
XPS under the slab is not an option.
I would prefer to skip the extra exterior wall insulation — the south side mostly consists of windows anyway (U-value 0.6), so there isn’t much wall left (maximum 50%).
Is increasing the roof insulation worthwhile?
To do or not? What do you think?
Thanks for any feedback
michael
Our project:
Single-family house according to the new 2016 energy saving regulations
Living area 150m² (1,615 sq ft) DIN
Roof insulation currently 24cm (9.5 inches) mineral wool, U-value 0.19
Exterior wall 17.5cm (7 inches) Poroton + 16cm (6 inches) EPS, U-value 0.19
Builder’s proposal:
Increase roof insulation to 30cm (12 inches), U-value then 0.16, additional cost $2,800
Increase exterior wall insulation to 20cm (8 inches) EPS, U-value then 0.16, additional cost $1,400
XPS under the slab is not an option.
I would prefer to skip the extra exterior wall insulation — the south side mostly consists of windows anyway (U-value 0.6), so there isn’t much wall left (maximum 50%).
Is increasing the roof insulation worthwhile?
To do or not? What do you think?
Thanks for any feedback
michael
I would choose a thicker brick and skip the insulation altogether.
We built monolithically with Poroton. Our wall is 36.5 cm (14.4 inches) thick, but the architect already said back then that according to the new energy-saving regulations, he would recommend a 42.5 cm (16.7 inches) brick.
We built monolithically with Poroton. Our wall is 36.5 cm (14.4 inches) thick, but the architect already said back then that according to the new energy-saving regulations, he would recommend a 42.5 cm (16.7 inches) brick.
ölschlamm schrieb:
Proposal from the developer:Why is he suggesting that?
Why do you get a U-value of 0.19 W/m²K with 24 cm (9.5 inches) of mineral wool in the roof? Even with a lambda of 0.04 W/mK, I calculate a U-value of 0.16 W/m²K. What kind of roof construction is that? At least with a purlin roof, the insulation thickness is eventually limited by the rafter thickness.
As for gluing EPS in front of Poroton, I think Manu would agree with me on that.
As for gluing EPS in front of Poroton, I think Manu would agree with me on that.
Hi Ölschlamm,
lastdrop’s question isn’t entirely unreasonable: Why is your builder suggesting this to you? Did they make a miscalculation and now fear that the proposed wall construction won’t comply with the Energy Saving Ordinance 2016? And are they looking for an easy way out?
It probably won’t pay off anyway. A house your size will likely have heating costs of around 500-600 € per year. Even if the additional insulation saved 25% of that (which is very unlikely—it would be much less!), you’re talking about savings of 150 euros annually. And for that, you’d have to invest 4200 €. Doesn’t sound like a good idea!
@Manu1976
Of course, building monolithically looks good at first, but it usually comes with a significant extra cost and you won’t achieve the insulation values of an external thermal insulation composite system (ETICS) / external wall insulation (EWI). And a T8 Poroton brick (unfilled) is also worse for sound insulation.
After some back and forth, we finally decided on 24 cm Poroton T18 plus 16 cm ETICS. That results in a U-value of 0.16, which should be sufficient.
Best regards,
Andreas
lastdrop’s question isn’t entirely unreasonable: Why is your builder suggesting this to you? Did they make a miscalculation and now fear that the proposed wall construction won’t comply with the Energy Saving Ordinance 2016? And are they looking for an easy way out?
It probably won’t pay off anyway. A house your size will likely have heating costs of around 500-600 € per year. Even if the additional insulation saved 25% of that (which is very unlikely—it would be much less!), you’re talking about savings of 150 euros annually. And for that, you’d have to invest 4200 €. Doesn’t sound like a good idea!
@Manu1976
Of course, building monolithically looks good at first, but it usually comes with a significant extra cost and you won’t achieve the insulation values of an external thermal insulation composite system (ETICS) / external wall insulation (EWI). And a T8 Poroton brick (unfilled) is also worse for sound insulation.
After some back and forth, we finally decided on 24 cm Poroton T18 plus 16 cm ETICS. That results in a U-value of 0.16, which should be sufficient.
Best regards,
Andreas
Oh, thanks for the answers
@Manu: We also considered thicker solid blocks at the beginning of the consultation. The energy saving regulation could still be met with 36.5cm (14 inches) aerated concrete. With Poroton bricks, not anymore, so definitely go thicker. A slim wall with external thermal insulation has the advantage of saving interior space since the insulation is applied on the outside. (A 10x10m (33x33 ft) foundation slab with 42.5cm (17 inches) blocks gives 91.7m² (987 sq ft) of living area, with 17.5cm (7 inches) blocks it’s 96.5m² (1,039 sq ft) – almost 10m² (108 sq ft) difference over two floors).
@lastdrop: He suggests this to still comply with the 2016 energy saving regulation using a gas boiler plus 10m² (108 sq ft) solar thermal system. Alternatively, 6cm (2.4 inches) XPS under the slab. A gas boiler including solar would be about the same price as a Rotex heat pump air-to-water system. But the additional cost for insulation is quite high considering the payback, since it would be in addition to the gas heating system. XPS would “only” cost around 1800 euros, but I am not sure if I want to take that risk.
@BeHaElJa: No idea about the collar beam roof, 24cm (9.5 inches) mineral wool – why would he give a worse value than there actually is?
@andimann: Your comment ultimately helps (if the numbers roughly add up). With an air-to-water heat pump, by my rough calculations, I’d get about 3000 kWh/year (annual performance factor 2.1 is realistic with panel radiators at 45°C (113°F) supply temperature – please no discussion, I want it this way! – and a very drafty high-altitude location on the Swabian Alb around 600m (2,000 ft) above sea level – it won’t be better than that), so electricity would cost about 750 euros.
With the gas system, I would have around 6000 kWh minus 1500 kWh from solar thermal = 4500 kWh, so about 260 euros.
Savings roughly 500 euros/year with additional costs of 9000 euros (gas tank, connection, chimney, etc.).
Add another 100 euros saving from the insulation, so 600 euros/year. Still probably not a good idea.
Looking forward to your opinions on this
michael
@Manu: We also considered thicker solid blocks at the beginning of the consultation. The energy saving regulation could still be met with 36.5cm (14 inches) aerated concrete. With Poroton bricks, not anymore, so definitely go thicker. A slim wall with external thermal insulation has the advantage of saving interior space since the insulation is applied on the outside. (A 10x10m (33x33 ft) foundation slab with 42.5cm (17 inches) blocks gives 91.7m² (987 sq ft) of living area, with 17.5cm (7 inches) blocks it’s 96.5m² (1,039 sq ft) – almost 10m² (108 sq ft) difference over two floors).
@lastdrop: He suggests this to still comply with the 2016 energy saving regulation using a gas boiler plus 10m² (108 sq ft) solar thermal system. Alternatively, 6cm (2.4 inches) XPS under the slab. A gas boiler including solar would be about the same price as a Rotex heat pump air-to-water system. But the additional cost for insulation is quite high considering the payback, since it would be in addition to the gas heating system. XPS would “only” cost around 1800 euros, but I am not sure if I want to take that risk.
@BeHaElJa: No idea about the collar beam roof, 24cm (9.5 inches) mineral wool – why would he give a worse value than there actually is?
@andimann: Your comment ultimately helps (if the numbers roughly add up). With an air-to-water heat pump, by my rough calculations, I’d get about 3000 kWh/year (annual performance factor 2.1 is realistic with panel radiators at 45°C (113°F) supply temperature – please no discussion, I want it this way! – and a very drafty high-altitude location on the Swabian Alb around 600m (2,000 ft) above sea level – it won’t be better than that), so electricity would cost about 750 euros.
With the gas system, I would have around 6000 kWh minus 1500 kWh from solar thermal = 4500 kWh, so about 260 euros.
Savings roughly 500 euros/year with additional costs of 9000 euros (gas tank, connection, chimney, etc.).
Add another 100 euros saving from the insulation, so 600 euros/year. Still probably not a good idea.
Looking forward to your opinions on this
michael
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