ᐅ Bricks T9/T10/T11/T12? Thermal Insulation vs. Soundproofing

Hello everyone,

Our single-family house construction is starting in September.
We have already chosen a structural brick with a thickness of 36.5 cm (14.4 inches).

Now we need to decide which specific type of brick to use. The main question is about thermal insulation versus soundproofing. Of course, good insulation is important, but I’m concerned that the house might become very echoey with a T9 brick.
The second question is whether anyone has any calculations or data on how much heating cost can be saved with a better brick, or how much more you pay with a lower-quality brick?

I would be very grateful for any answers!

Thank you very much.
Margarete

The U-value is your friend
You can no longer build with 365 mm T10 as it, in my opinion, exceeds the maximum allowable U-value for exterior walls.
It should probably be T9, T8, or T7 instead:
T9 with 180 m² (1937 sq ft) of exterior walls: 2433 kWh heat loss through the wall -> 162 € per year (gas)
T8 with 180 m² (1937 sq ft) of exterior walls: 2028 kWh heat loss through the wall -> 135 € per year (gas)
T7 with 180 m² (1937 sq ft) of exterior walls: 1637 kWh heat loss through the wall -> 108 € per year (gas)

Over 50 years (people rarely live in houses longer than this) assuming I can’t make any assumptions (since I don’t know your costs, how gas prices will develop, or if you’ll be heating with geothermal energy) – simply put: 1400 € saved going from T9 to T8, and 1350 € saved going from T8 to T7.

Where do your values come from?

Regards, Bauexperte

U-value heat demand calculator for 180 m² (1,938 sq ft) of exterior wall (considering only the exterior wall) using the U-values of the bricks at 365 mm (14 inches), 450 m³ (15,900 cubic feet) of indoor air volume, controlled residential ventilation with 80% heat recovery at 0.5 air changes per hour, -12°C (10°F) design temperature in the North German lowlands, with an indoor temperature of 21°C (70°F). Prices from the local gas supplier. Many assumptions, no guarantees, only to be regarded as a rough estimate.
It may be colder in Bavaria, so I assume the calculation might be more relevant there.

BeHaElJa schrieb:
The U-value is your friend
You definitely cannot build with 365 mm T10 anymore, as in my opinion it exceeds the maximum allowed U-value for exterior walls.
It should rather be T9, T8, or T7:
T9 with 180 m² (1937 sq ft) of exterior wall: 2433 kWh heat loss through the wall → €162 per year (gas)
T8 with 180 m² (1937 sq ft) of exterior wall: 2028 kWh heat loss through the wall → €135 per year (gas)
T7 with 180 m² (1937 sq ft) of exterior wall: 1637 kWh heat loss through the wall → €108 per year (gas)

Over 50 years (people rarely live in houses longer than that), assuming I cannot make assumptions (since I don’t know your costs or how gas prices will develop, or whether you will heat with geothermal energy) — simply put: €1400 savings from T9 to T8, €1350 savings from T8 to T7.

Interesting.. I will compare the cost side, but for a planned 150 m² (1615 sq ft) house.
The upgrade from Ytong (aerated concrete) to T9 costs about €8500, and from Ytong to T8 about €10,000; I don’t know the cost for T7, but maybe another €2000–3000 more.

We’re also constantly calculating... Since KfW70 will be discontinued next year, it will get difficult for us, as we do not want an air-to-water heat pump.

Regards

And what became of the life project? Have you found the universal formula that finally shows us all that insulation is not cost-effective?