ᐅ Achievable minimum indoor temperature with KfW55-standard building
Created on: 17 Nov 2023 10:14
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Kia1344
Hello everyone,
I hope this post is in the right place.
We have a new apartment in a building constructed to the KfW55 standard. The apartment has underfloor heating and does not get warmer than 20 degrees Celsius (68°F). According to the developer, this is due to the KfW55 standard. So the maximum room temperature would be expected. However, 20 degrees Celsius (68°F) is too cold for us. Cooking is minimal, and the apartment is unoccupied during the day. There is also not enough solar gain, meaning no other heat sources are present. Therefore, the heating should be able to reach 21 or 22 degrees Celsius (70–72°F) for a comfortable climate.
Does anyone have information on whether the statement that the heating system can only reach 20 degrees Celsius (68°F) due to the KfW55 standard is actually correct? Thank you very much.
I hope this post is in the right place.
We have a new apartment in a building constructed to the KfW55 standard. The apartment has underfloor heating and does not get warmer than 20 degrees Celsius (68°F). According to the developer, this is due to the KfW55 standard. So the maximum room temperature would be expected. However, 20 degrees Celsius (68°F) is too cold for us. Cooking is minimal, and the apartment is unoccupied during the day. There is also not enough solar gain, meaning no other heat sources are present. Therefore, the heating should be able to reach 21 or 22 degrees Celsius (70–72°F) for a comfortable climate.
Does anyone have information on whether the statement that the heating system can only reach 20 degrees Celsius (68°F) due to the KfW55 standard is actually correct? Thank you very much.
An electric towel radiator is installed in the bathroom, intended to achieve 24°C (75°F). There is underfloor heating in the bathroom as well. However, with only that, we can no longer reach 24°C (75°F).
This is a new development with several hundred apartments. I am still reviewing the building specifications. I have never had a problem with heating before. Every new construction seems to be an adventure.
This is a new development with several hundred apartments. I am still reviewing the building specifications. I have never had a problem with heating before. Every new construction seems to be an adventure.
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WilderSueden17 Nov 2023 13:49Towel radiators are quite common since bathrooms, being small exhaust spaces, are expected to reach the highest temperatures. A temperature of 24°C (75°F) is already quite ambitious with the typical flow temperatures used today.
I would guess that the flow rate is set too low. But just to be sure, what exactly has the tenant set on the thermostats? Are they all set to the highest level? Do all the valves on the manifold then open?
I would guess that the flow rate is set too low. But just to be sure, what exactly has the tenant set on the thermostats? Are they all set to the highest level? Do all the valves on the manifold then open?
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WilderSueden17 Nov 2023 14:07Where is the apartment located within the building? Does it have more exterior walls than the neighboring units?
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KarstenausNRW17 Nov 2023 14:11The topic becomes really interesting when the temperature actually drops to -15°C (5°F).
In my opinion, one of the following issues might be the cause:
- The entire heating system was incorrectly designed (either in the planning or technically—for example, some heating circuits might be turned down more or less)
- The hydraulic balancing was not done properly
- The heat generator is so undersized that it barely manages to maintain 20°C (68°F) inside the home during mild autumn days, and in winter it might only reach around 12°C (54°F)
- The heating (heating curve) is set too low, limiting the achievable temperature. This could be adjusted directly on the heating system.
In my opinion, one of the following issues might be the cause:
- The entire heating system was incorrectly designed (either in the planning or technically—for example, some heating circuits might be turned down more or less)
- The hydraulic balancing was not done properly
- The heat generator is so undersized that it barely manages to maintain 20°C (68°F) inside the home during mild autumn days, and in winter it might only reach around 12°C (54°F)
- The heating (heating curve) is set too low, limiting the achievable temperature. This could be adjusted directly on the heating system.
Silly question, but I’ve already read every possible scenario here in the forum...
Your tenant is keeping the windows closed, right?
I vaguely remember a recent post where the original poster complained about high heating costs, but it turned out they had the window constantly open in the storage room because of the vegetables... 😀
Otherwise, I agree that KfW55 certainly doesn’t mean higher indoor temperatures. We just built to KfW55 standard and are experiencing our first heating season. To keep the air comfortably dry, we maintain a cozy warm temperature throughout the house (T-shirt weather). This is no problem if you’re willing to invest the money.
I hope the house is not being heated with a heat pump system that might be undersized? That would cause serious problems during a proper winter, probably not just for your tenant. I’d also be curious to hear what the neighbors say.
Your tenant is keeping the windows closed, right?
I vaguely remember a recent post where the original poster complained about high heating costs, but it turned out they had the window constantly open in the storage room because of the vegetables... 😀
Otherwise, I agree that KfW55 certainly doesn’t mean higher indoor temperatures. We just built to KfW55 standard and are experiencing our first heating season. To keep the air comfortably dry, we maintain a cozy warm temperature throughout the house (T-shirt weather). This is no problem if you’re willing to invest the money.
I hope the house is not being heated with a heat pump system that might be undersized? That would cause serious problems during a proper winter, probably not just for your tenant. I’d also be curious to hear what the neighbors say.
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