ᐅ KfW 40 or better in solid construction without additional insulation possible?
Created on: 18 Nov 2019 08:44
S
Specki
Hello,
I was initially set on a timber frame construction for my future house. However, I am now reconsidering solid construction because it does have its advantages. Ideally, I would prefer this without additional external insulation, as that would be redundant and insulation typically does not last as long as the masonry itself. Poroton seems the most appealing option to me at first glance.
But is that even feasible? Are there bricks (or other solid building blocks) that on their own meet the KfW 40 standard, or possibly perform even better?
Does anyone have experience with this? Has anyone actually built something like this?
I’m open to discussion if you believe additional insulation makes sense. However, no “Styrofoam” will be used on the exterior walls; if anything, it will be an alternative material.
The comments I would rather avoid are those suggesting a lower energy standard would be sufficient. I will not build anything below KfW 40.
Thanks in advance for your input.
Best regards,
Specki
I was initially set on a timber frame construction for my future house. However, I am now reconsidering solid construction because it does have its advantages. Ideally, I would prefer this without additional external insulation, as that would be redundant and insulation typically does not last as long as the masonry itself. Poroton seems the most appealing option to me at first glance.
But is that even feasible? Are there bricks (or other solid building blocks) that on their own meet the KfW 40 standard, or possibly perform even better?
Does anyone have experience with this? Has anyone actually built something like this?
I’m open to discussion if you believe additional insulation makes sense. However, no “Styrofoam” will be used on the exterior walls; if anything, it will be an alternative material.
The comments I would rather avoid are those suggesting a lower energy standard would be sufficient. I will not build anything below KfW 40.
Thanks in advance for your input.
Best regards,
Specki
Specki schrieb:
How about lower heating costs over the next 60 years....
KFW55 is not really an option for me. More in the other direction, towards passive house standard insulation.That is complete nonsense; you are harming the environment, your wallet, and your peace of mind!Bookstar schrieb:
That’s complete nonsense, you’re harming the environment, your wallet, and your nerves!That’s your opinion. I see it a bit differently.With a KFW55 standard, my heating demand is 35 kWh/m² (3.25 kWh/ft²).
With KFW40, it’s only 25 kWh/m² (2.32 kWh/ft²).
With a Passive House, it goes down to just 15 kWh/m² (1.39 kWh/ft²).
This means that over many decades, I would only need 71% or even 42% of the heating energy.
So, if I’m not making a mistake here, I think that makes a huge difference.
N
nordanney18 Nov 2019 15:31Specki schrieb:
For a KFW55 house, I have a heating energy demand of 35 kWh/m² (3.3 kWh/ft²)
For KFW40, only 25 kWh/m² (2.3 kWh/ft²)
For a Passive House, only 15 kWh/m² (1.4 kWh/ft²)
That means that over many decades I would only need 71% or even 42% of the heating energy.Only on paper. You can still have higher heating costs in a KFW40 house than in a KFW55 house. This is just theory based on technical data and calculations. Real life often looks different.Yes, that's how it is; you can no longer base it purely on raw numbers in this area. Financially, you can calculate that payback is impossible. It harms the environment because you have excessive resource consumption, whether it’s EPS, mineral wool, or something else. The construction risk also increases since very meticulous work is required for sealing and related aspects.
Better opt for KFW55, controlled mechanical ventilation, photovoltaic systems, and geothermal energy. That way, you’re doing something good, even if it takes a long time to pay off.
Better opt for KFW55, controlled mechanical ventilation, photovoltaic systems, and geothermal energy. That way, you’re doing something good, even if it takes a long time to pay off.
Specki schrieb:
For KFW55, I have a heating demand of 35 kWh/m² (3.25 kWh/ft²).
For KFW40, only 25 kWh/m² (2.32 kWh/ft²).
For Passive House, just 15 kWh/m² (1.39 kWh/ft²).
This means that I need only 71% or even 42% of the heating energy over many decades. Even if I used the most sophisticated, expensive, and versatile energy form, namely electric power, at 26 cents/kWh, that would be:
For KFW55: 9.1 euros/m² (0.85 dollars/ft²)
For KFW40: 6.5 euros/m² (0.61 dollars/ft²)
For Passive House: 3.9 euros/m² (0.37 dollars/ft²)
So a difference of 5.2 euros/m² (0.48 dollars/ft²). For 140 m² (1507 ft²), that would be about 700 euros (about 810 dollars). But how much more can you afford
a) as a one-time investment,
b) in increased maintenance costs?
Your actual heating energy cost per kWh will be significantly lower than electricity — so the calculation shifts correspondingly to your disadvantage.
Similar topics