ᐅ New construction KfW55 energy standard with gas heating, solar panels, and controlled ventilation system with heat recovery
Created on: 22 Oct 2016 14:03
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XeNiA
Hello!
We are just starting the planning of our new build, and the big question we keep discussing is the heating system.
We are building a detached single-family house with 145 sq m (1560 sq ft) plus an expanded attic of about 40 sq m (430 sq ft) with underfloor heating (including in the attic).
We want to achieve KfW55 standard. The house will be built with solid masonry and brick veneer.
One thing we definitely want is a controlled ventilation system with heat recovery.
The most cost-effective option so far seems to be a combination of gas, solar thermal, and ventilation. The construction companies we are requesting quotes from are also offering a KfW55 package with improved insulation, as it might be difficult to meet the required standards otherwise.
An alternative (the second most affordable option) would be an air-to-air heat pump instead of gas.
What are the advantages and disadvantages of these two heating systems? What would the approximate expected monthly costs be?
Some heating installers have told us that achieving KfW55 with gas is not possible at all.
We are quite confused, and everyone says something different.
What are your experiences?
Thank you very much!
We are just starting the planning of our new build, and the big question we keep discussing is the heating system.
We are building a detached single-family house with 145 sq m (1560 sq ft) plus an expanded attic of about 40 sq m (430 sq ft) with underfloor heating (including in the attic).
We want to achieve KfW55 standard. The house will be built with solid masonry and brick veneer.
One thing we definitely want is a controlled ventilation system with heat recovery.
The most cost-effective option so far seems to be a combination of gas, solar thermal, and ventilation. The construction companies we are requesting quotes from are also offering a KfW55 package with improved insulation, as it might be difficult to meet the required standards otherwise.
An alternative (the second most affordable option) would be an air-to-air heat pump instead of gas.
What are the advantages and disadvantages of these two heating systems? What would the approximate expected monthly costs be?
Some heating installers have told us that achieving KfW55 with gas is not possible at all.
We are quite confused, and everyone says something different.
What are your experiences?
Thank you very much!
Hello everyone!
We’re starting construction next week and still haven’t planned for solar energy. The energy efficiency funding application was approved a while ago, and we can manage without solar.
I will check the exact details later. I only know that our exterior walls will be about 48cm (19 inches) thick. They will be double-skin masonry. We will have additional insulation on the ground slab and windows with a U-value of 0.7.
Regards
We’re starting construction next week and still haven’t planned for solar energy. The energy efficiency funding application was approved a while ago, and we can manage without solar.
I will check the exact details later. I only know that our exterior walls will be about 48cm (19 inches) thick. They will be double-skin masonry. We will have additional insulation on the ground slab and windows with a U-value of 0.7.
Regards
ares83 schrieb:
@Nordlys With an air-to-water heat pump, achieving KfW55 standard isn’t much of a problem due to the better efficiency factor. The real challenge here is using gas.That’s true.
Controlled mechanical ventilation with heat recovery can replace solar thermal systems to cover the renewable share. However, the investment cost is likely higher than building a solar thermal system. On the plus side, you gain the benefits of controlled ventilation.
Another alternative would be biogas, if available (which is likely rare).
Hello! I have a question for the experienced members:
Do the requirements for the KfW55 loan align with the prerequisites for the heat demand calculation needed for the building permit/planning permission? In other words: can I meet the conditions for building my single-family house with gas heating and controlled mechanical ventilation, but without solar thermal (ST), yet still not qualify for the KfW loan? Regards, does02
Do the requirements for the KfW55 loan align with the prerequisites for the heat demand calculation needed for the building permit/planning permission? In other words: can I meet the conditions for building my single-family house with gas heating and controlled mechanical ventilation, but without solar thermal (ST), yet still not qualify for the KfW loan? Regards, does02
B
Bieber081514 Feb 2017 17:34@does02 Yes, you are allowed to build without meeting KfW55 standards. The minimum requirements are regulated by the energy saving ordinance / energy efficiency regulations.
Another update from us: Today we received confirmation from the KfW consultant: KfW 55 according to the reference value method and system technology gas/ST & controlled residential ventilation with wall construction 3/4 clinker brick and 1/4 plastered: bottom 17.5 cm (7 inches) calcium silicate brick + 16 cm (6.3 inches) insulation, thermal conductivity class 032 – 11.5 cm (4.5 inches) clinker brick – top 17.5 cm (7 inches) calcium silicate brick – 16 cm (6.3 inches) ETICS insulation, thermal conductivity class 032 (possibly also 18 cm (7 inches) thermal conductivity class 035, because we want mineral insulation) – 1 cm (0.4 inches) synthetic resin plaster)
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