Hello,
we received a quote for a single-family house built according to the Energy Saving Ordinance from a builder, who offers the following exterior wall construction:
- 17.5 cm (7 inches) aerated concrete
- Mineral fiber insulation mat with a minimum thickness of 14 cm (5.5 inches) according to the thermal protection certificate (thermal conductivity 0.035 W/mK)
- 11.5 cm (4.5 inches) facing brick
What is the evaluation of these materials regarding thermal insulation and soundproofing?
Are there quality differences in this construction as well?
For an additional cost of €2,000, the following upgrades are available:
- 140 mm (5.5 inches) cavity insulation with a thermal conductivity of 0.035 W/mK in the facing brickwork
- 180 mm (7 inches) mineral wool insulation with a thermal conductivity of 0.035 W/mK in the rafter area
- 240 mm (9.5 inches) mineral wool insulation with a thermal conductivity of 0.035 W/mK in the collar beam area
- 100 mm (4 inches) polystyrene rigid foam insulation with a thermal conductivity of 0.035 W/mK under the ground floor screed
With a solar system for domestic hot water preparation, which costs almost €7,000, KfW 70 standard could be achieved.
What do you think about this?
Is the standard specification sufficient, and is the upgrade worth the additional cost?
we received a quote for a single-family house built according to the Energy Saving Ordinance from a builder, who offers the following exterior wall construction:
- 17.5 cm (7 inches) aerated concrete
- Mineral fiber insulation mat with a minimum thickness of 14 cm (5.5 inches) according to the thermal protection certificate (thermal conductivity 0.035 W/mK)
- 11.5 cm (4.5 inches) facing brick
What is the evaluation of these materials regarding thermal insulation and soundproofing?
Are there quality differences in this construction as well?
For an additional cost of €2,000, the following upgrades are available:
- 140 mm (5.5 inches) cavity insulation with a thermal conductivity of 0.035 W/mK in the facing brickwork
- 180 mm (7 inches) mineral wool insulation with a thermal conductivity of 0.035 W/mK in the rafter area
- 240 mm (9.5 inches) mineral wool insulation with a thermal conductivity of 0.035 W/mK in the collar beam area
- 100 mm (4 inches) polystyrene rigid foam insulation with a thermal conductivity of 0.035 W/mK under the ground floor screed
With a solar system for domestic hot water preparation, which costs almost €7,000, KfW 70 standard could be achieved.
What do you think about this?
Is the standard specification sufficient, and is the upgrade worth the additional cost?
Do you live on a main road? If not, soundproofing is not such a big issue. It becomes more interesting when it comes to the interior walls.
We are still building with sand-lime brick (175mm (7 inches) sand-lime brick, 160mm (6.3 inches) mineral wool, 115mm (4.5 inches) facing brick), but mainly because we want interior walls made of sand-lime brick as well, and we believe its higher thermal mass offers some benefit.
The theoretical insulation advantage of aerated concrete in our case amounts to about 700 kWh per year—so roughly $35 (ground-source heat pump with a seasonal performance factor of about 4.5). With gas heating, that would be around $50 (assuming the cubic meter still costs 70 cents).
We are still building with sand-lime brick (175mm (7 inches) sand-lime brick, 160mm (6.3 inches) mineral wool, 115mm (4.5 inches) facing brick), but mainly because we want interior walls made of sand-lime brick as well, and we believe its higher thermal mass offers some benefit.
The theoretical insulation advantage of aerated concrete in our case amounts to about 700 kWh per year—so roughly $35 (ground-source heat pump with a seasonal performance factor of about 4.5). With gas heating, that would be around $50 (assuming the cubic meter still costs 70 cents).
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