Hello
We are currently considering selling our house built in 2000 and building a new one.
You often hear that the house should be insulated as well as possible, and so on. But what insulation is actually good, and what is a reasonable compromise in terms of cost and benefit? We have quite clear ideas about how the house should look, yet every builder comes up with different suggestions. Only Poroton blocks are agreed on by all.
Here are the basic details:
3-gable house
12 x 9.5 meter (31 ft x 31 ft) beam structure with a 1 meter (3 ft) overhang on one third of the garden side, so then 10.5 meters (34 ft)
1 meter (3 ft) knee wall
Mechanical ventilation with heat recovery
Underfloor heating in all rooms
Minimum KfW 70 standard achieved through insulation, not technology
Builder 1 offers 24 cm (9.5 inches) walls + 16 cm (6 inches) external thermal insulation composite system (ETICS) with 0.40 W/m²K roof insulation 20 cm (8 inches) 0.35 W/m²K
Builder 2 offers 17.5 cm (7 inches) walls + 16 cm (6 inches) ETICS and 20 cm (8 inches) roof insulation 0.35 W/m²K
Builder 3 suddenly wants to achieve this with 17.5 cm (7 inches) walls and only 10 cm (4 inches) ETICS.
We currently favor builder 1, even though they are significantly more expensive (about 15,000 euros). I would like to know if the insulation they offer is really good or rather below standard, so some improvements would be necessary. I would appreciate advice to clarify this.
Olli
We are currently considering selling our house built in 2000 and building a new one.
You often hear that the house should be insulated as well as possible, and so on. But what insulation is actually good, and what is a reasonable compromise in terms of cost and benefit? We have quite clear ideas about how the house should look, yet every builder comes up with different suggestions. Only Poroton blocks are agreed on by all.
Here are the basic details:
3-gable house
12 x 9.5 meter (31 ft x 31 ft) beam structure with a 1 meter (3 ft) overhang on one third of the garden side, so then 10.5 meters (34 ft)
1 meter (3 ft) knee wall
Mechanical ventilation with heat recovery
Underfloor heating in all rooms
Minimum KfW 70 standard achieved through insulation, not technology
Builder 1 offers 24 cm (9.5 inches) walls + 16 cm (6 inches) external thermal insulation composite system (ETICS) with 0.40 W/m²K roof insulation 20 cm (8 inches) 0.35 W/m²K
Builder 2 offers 17.5 cm (7 inches) walls + 16 cm (6 inches) ETICS and 20 cm (8 inches) roof insulation 0.35 W/m²K
Builder 3 suddenly wants to achieve this with 17.5 cm (7 inches) walls and only 10 cm (4 inches) ETICS.
We currently favor builder 1, even though they are significantly more expensive (about 15,000 euros). I would like to know if the insulation they offer is really good or rather below standard, so some improvements would be necessary. I would appreciate advice to clarify this.
Olli
DerBjoern schrieb:
.
Walls made of 36cm (14 inch) T9 blocks aren’t exactly great either. They result in a U-value of around 0.235 W/m²K. That’s rather at the lower end these days.So what? It’s not just about the blocks, but the whole package. Together with the air-to-water heat pump and insulation of the ground slab, plus good (better than standard) triple-glazed windows, we are, according to calculations, not far from KfW55 standard. That’s sufficient for us.
D
DerBjoern13 Oct 2014 13:08Yes, that can certainly be enough if significantly more than necessary is done in other areas. The heat pump then covers the rest for the heating demand (Qp). I just wanted to mention it since the original poster specifically noted
Min. KfW 70 on insulation, not technology. All good! 😉
blockhauspower13 Oct 2014 15:08Sorry, but before discussing U-values of 23.5 and insulation U-values of 0.4 without specifying the thickness, it’s important to get informed first.
The target U-value for vertical exterior walls is 0.24 W/m²*K, and insulation typically has a thermal conductivity of about 0.035 W/m*K (thermal conductivity category 035).
Best regards
The target U-value for vertical exterior walls is 0.24 W/m²*K, and insulation typically has a thermal conductivity of about 0.035 W/m*K (thermal conductivity category 035).
Best regards
D
DerBjoern13 Oct 2014 15:32No need to inform me, I simply overlooked the powers of ten in a hurry... happens when you're rushed...
Thanks for the clarification. ^^
Thanks for the clarification. ^^
blockhauspower13 Oct 2014 15:42:-)
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