ᐅ Retrofitting an air conditioning system – will that affect KfW funding?
Created on: 10 Jun 2021 21:02
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Helado
Good evening everyone,
Since October, we have been living in a prefabricated house built by Hanse Haus. We have been living here for about 5 months now and are very pleased.
However, at the moment, the indoor temperature in each room is between 26°C and 28°C (79°F and 82°F), even though it is similarly warm outside. The only way we can lower the temperature is by opening the windows at night.
We have a KFW55 standard and a Stiebel Eltron LWZ 5s Plus. Unfortunately, it does not have an active cooling function, but we have installed and activated the summer cassette in the menu settings. So far, this has not produced the desired result. The temperature remains the same.
We are now considering adding air conditioning, but we have been clearly advised that this might mean no longer meeting the KFW energy-saving regulation standards, and therefore, it might affect the eligibility for subsidies. Fortunately, it is not very hot outside at the moment, but when it reaches 35°C (95°F) outdoors, the temperature inside the house can easily rise to around 30°C (86°F), which is not exactly comfortable.
Does anyone have advice or experience with retrofitting air conditioning (in specific rooms) or with the same heating system?
Thanks & best regards
Helado
Since October, we have been living in a prefabricated house built by Hanse Haus. We have been living here for about 5 months now and are very pleased.
However, at the moment, the indoor temperature in each room is between 26°C and 28°C (79°F and 82°F), even though it is similarly warm outside. The only way we can lower the temperature is by opening the windows at night.
We have a KFW55 standard and a Stiebel Eltron LWZ 5s Plus. Unfortunately, it does not have an active cooling function, but we have installed and activated the summer cassette in the menu settings. So far, this has not produced the desired result. The temperature remains the same.
We are now considering adding air conditioning, but we have been clearly advised that this might mean no longer meeting the KFW energy-saving regulation standards, and therefore, it might affect the eligibility for subsidies. Fortunately, it is not very hot outside at the moment, but when it reaches 35°C (95°F) outdoors, the temperature inside the house can easily rise to around 30°C (86°F), which is not exactly comfortable.
Does anyone have advice or experience with retrofitting air conditioning (in specific rooms) or with the same heating system?
Thanks & best regards
Helado
pagoni2020 schrieb:
Could you explain in more detail how you did that?
Which devices? How were they installed?
Do you have any pictures? Three separate units from the hardware store, one of which has now failed after 15 years. It is being replaced by a Panasonic inverter system.
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Reltaw202116 Jun 2021 09:39hampshire schrieb:
A fan aimed at a chair with a damp towel provides quick, effective, and quite affordable cooling. The evaporation helps.And if it’s a nice Chippendale chair or lounge furniture paired with a Gucci towel, there’s something for the eye as well 😉
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Reltaw202116 Jun 2021 09:53Grundaus schrieb:
Three separate units from the hardware store, one of which just broke after 15 years. It will be replaced by a Panasonic inverter system. Do you not need any piping for condensate or exhaust/supply air?
I actually want underfloor heating that can also cool by a few degrees. But I’m already noticing that this could compromise the KW40 standard, which is why the house builder is hesitant.
In other words: I want to start preparing a second network with your help (in both meanings). Even though the salesperson keeps insisting that we don’t need this because of the existing shading. I think the large windows on the south side will at best balance this out. There is no shading outside from other buildings or vegetation either. If the outside air no longer cools down to around 20°C (68°F) at night, it won’t be enough.
The towel rail suggestion is interesting, of course, but if that doesn’t suffice, you’ll regret not having installed ducts when you still could have.
K1300S schrieb:
The installer has already complained that no openings were planned for the various pipes. I think if you install everything completely afterwards, the effort will be even greater than in a partially prepared shell.But it’s certainly not a major issue. This is done thousands of times every day. The HVAC industry is more active than ever since the energy saving regulations.Reltaw2021 schrieb:
Don’t you need pipes for condensate or exhaust/supply air for that?You need two insulated copper pipes of the appropriate diameter from the indoor unit to the outdoor unit (connections and mixed types are also possible). Then, for each indoor<>outdoor unit, power/control wiring and a condensate drain at each indoor unit.Reltaw2021 schrieb:
I actually want underfloor heating that can also cool by a few degrees. But I’m already noticing that this puts the KW40 standard at risk and that’s why the house manufacturer is hesitant.That’s exactly where underfloor heating provides those few degrees—at the floor. But usually you’re not lying directly on the floor, you sit on a chair/sofa or lie in bed. The temperature there is quite different and you won’t notice those few degrees from the floor. Also, humidity plays a role, which underfloor heating can’t remove, so you don’t really gain anything from the much-praised cooling via underfloor heating. If it costs more than 200-300 Euros extra, you can skip this option.Reltaw2021 schrieb:
Even though the salesperson keeps insisting we don’t need this due to the existing wiring. I think the large windows on the south side will at best balance it out. Outside, there is no shading from other buildings or vegetation. If the outside air doesn’t cool down by at least 20°C (36°F) at night, it won’t be enough.In other words, you’re building a modern house and you need an air conditioning system. (Based on experience).B
BBaumeister16 Jun 2021 10:10I wouldn’t agree with the idea that it’s “not necessary.” Good insulation blocks a lot of heat, and when it gets really hot outside, it still takes a while for that heat to reach the inside. We shade the entire house during the day, have a building to KfW 55 standard, run the ventilation system at night with the bypass open and on a high setting, and create cross-ventilation throughout the house early in the morning. Still, during longer heatwaves, the temperature eventually rises indoors, and there are times when nighttime temperatures stay well above 20°C (68°F). In such cases, an air conditioning system is ideal and, with relatively low power, can cool everything quite effectively.
In my experience, it’s better to run the system all day at a very low setting to prevent the walls and furniture from overheating. This way, the coolness lasts throughout the night, even when the air conditioning is turned off.
In my experience, it’s better to run the system all day at a very low setting to prevent the walls and furniture from overheating. This way, the coolness lasts throughout the night, even when the air conditioning is turned off.
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AllThumbs16 Jun 2021 10:28BBaumeister schrieb:
I wouldn’t quite agree with the idea that it’s “not necessary.” Good insulation blocks a lot of heat, and when it gets really hot, it takes a while for the heat to penetrate inside. During the day, we shade the entire house, have KfW 55 standard, run the ventilation system at night with the bypass open and at high setting, and open all windows early in the morning for cross ventilation. Still, during prolonged heat waves, the indoor temperature eventually rises, and there are nights when it stays well above 20°C (68°F). In those cases, having an air conditioning system is excellent, and with relatively low power, you can cool everything quite well.
From my experience, it’s better to run the unit all day at a very low setting to prevent walls and furniture from heating up. Then the coolness lasts throughout the night, even when the air conditioning is switched off. How many rooms do you have an indoor unit in? I’m considering where it might make sense to have a provision and whether the mechanical ventilation system might help distribute the cool air a bit as well?
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