ᐅ Bricks: Are differences in thermal conductivity of 0.03 noticeable?

IOSam23 schrieb:

Is the difference between 0.07 and 0.10 W/mK really noticeable in a house, or is it rather negligible? Will I need to heat significantly more if I choose 0.10?

Thermal conductivity values should be understood as linear, unlike sound levels. So, your two comparison materials have a ratio of 7:10 in this respect. Practically, with the "better" material, heat passes through in ten hours what passes through the other in just seven hours. This is not negligible but clearly significant in calculations. However, you set your thermostats to target temperatures, not to compensate for heat loss directly. Therefore, your heating bill will indeed be noticeably affected. Still, I would prioritize the overall heating cost over just focusing on the material’s thermal conductivity.

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11ant schrieb:

However, I would always prioritize my personal brick preference over the heating bill.

I know this is a topic on its own, and in my case, it will be a red clay brick. Am I way off with something like an MZ10 with 0.1 (W/m²K), and should I worry about keeping my house comfortably warm in winter or sweating during summer?

IOSam23 schrieb:

Am I completely off track with, for example, an MZ10 with 0.1, and should I be worried about keeping my house comfortably warm in winter or sweating in summer?

Let me say it once more so you finally understand. Any house will become comfortably warm. Even if you use 0.30 (30cm (12 inches)) blocks. You just have to heat more.
Understood?

Oh, and you have to meet the KfW55 standard anyway. If your MZ10 is sufficient for that, you have a new build that complies with legal requirements and is built thousands of times across Germany (to be understood as an overall package, not referring to a single product like one block).

IOSam23 schrieb:

Am I completely off with something like an MZ10 with 0.1, and do I need to worry about keeping my house comfortably warm in winter or sweating in summer?

"My" house is as old as I am, made of monolithic pumice concrete with a thickness of 300 millimeters (12 inches). You can stand being inside at any time of the year. My annual energy report shows I’m generally around the average. Just relax, and definitely don’t plan your house focusing solely on that. We don’t even use sand-lime brick for the party walls in our apartment, yet I can’t hear the dog next door (in case that would be your next concern after checking the thermal transmittance).

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nordanney schrieb:

In your example, user behavior probably affects the differences much more than the different types of bricks.

In my opinion, that’s a strong argument applicable to every user. The now widely accepted expectation of high indoor temperatures definitely increases energy consumption more than the choice of a particular building material. Of course, nobody wants to be cold, but I often hear and read about seemingly indispensable temperature standards that actually cause higher energy use rather than being preventable through building design.

I currently live in a very well-insulated house (better than KfW 40 standard) and would never go back, not just because of subsidies or any required standards. There are winter days when the heating doesn’t run at all because the insulation keeps the heat inside. Adding extra insulation in some places and less in others doesn’t make sense; there needs to be a consistent concept or a clear goal to maximize insulation. In my opinion, even in summer, despite having a south-facing side, it doesn’t heat up as much as our old house (made with 36cm (14 inches) Poroton bricks).

This definitely pays off, whether in resale value or heating costs, but right now it also provides a noticeable added comfort that I consider worth the effort. So you should consider from the start whether these aspects matter to you and then follow through consistently (foundation slab, windows, wall insulation, roof insulation, etc.) or not; in that case, the “standard” approach your builder offers is sufficient to create a comfortable home.

It has also become somewhat of a trend to emphasize these values so strongly; what really matters is the overall project.

IOSam23 schrieb:

If I have a photovoltaic system with storage

I would rather consider the storage more of a "gimmick," even though I have one myself. I would definitely invest more in the insulation of the house. Maybe you can find a few points here and there, and just like that, the insulation might even pay for itself.