Dear community,
My wife and I are currently working with a general contractor to dive into the detailed building planning.
One of our main concerns is a proper air conditioning system for the house.
The project currently includes about 300m2 (3,230 sq ft) of living space plus a basement (ground floor + first floor + attic); KFW 55 standard plus photovoltaic system (sizing still to be decided).
We both have previous negative experience, having lived for over 10 years in apartments where indoor temperatures in summer uncontrollably reached 32-35°C (90-95°F). This has to stop.
Therefore, our original idea was to plan for air conditioning units in the key rooms right from the start (individual air conditioning units). Now I also understand that a heat pump can cool a few degrees below the outdoor temperature. At summer temperatures above 30°C (86°F), that would not be enough for me.
So my question is: do you have any experience with this? Does this thinking make sense, or would you say that a proper heat pump with cooling function is definitely sufficient?
Of course, we are aware that whole-house air conditioning adds extra costs. But is the investment worthwhile?
My wife and I are currently working with a general contractor to dive into the detailed building planning.
One of our main concerns is a proper air conditioning system for the house.
The project currently includes about 300m2 (3,230 sq ft) of living space plus a basement (ground floor + first floor + attic); KFW 55 standard plus photovoltaic system (sizing still to be decided).
We both have previous negative experience, having lived for over 10 years in apartments where indoor temperatures in summer uncontrollably reached 32-35°C (90-95°F). This has to stop.
Therefore, our original idea was to plan for air conditioning units in the key rooms right from the start (individual air conditioning units). Now I also understand that a heat pump can cool a few degrees below the outdoor temperature. At summer temperatures above 30°C (86°F), that would not be enough for me.
So my question is: do you have any experience with this? Does this thinking make sense, or would you say that a proper heat pump with cooling function is definitely sufficient?
Of course, we are aware that whole-house air conditioning adds extra costs. But is the investment worthwhile?
driver55 schrieb:
Usually around 22°C (72°F) in the mornings, sometimes even less, and about 23.5°C (74°F) in the evenings. Upstairs it’s generally 1 degree higher. Mostly shaded and passive cooling is achieved through the underfloor heating system. (KfW60 timber frame house)Cool, so that means the passive cooling reduces the temperature by almost 1–2 degrees for you?
HausiKlausi24 Jul 2022 22:39No offense (I don’t know the details of the project). But what I don’t understand is: For such a large-scale project that apparently has a solid financial foundation, why invest so much extra money in air conditioning (treating the symptoms) instead of raising the energy efficiency standard even higher and also ensuring adequate external shading, planting, and trees with minimal hardscape? These things are not mutually exclusive, and air conditioning can still be used. However, my priorities would be different. Have you really explored all options in this regard?
Snowy36 schrieb:
Cool, so the passive cooling lowers the temperature by almost 1-2 degrees for you?Probably closer to a full 3 degrees. It’s been running continuously for over three weeks now. At first at 20°C (68°F)... then 19°C (66°F), and for more than a week now at 18°C (64°F) supply temperature. In the bathroom, I reduced the flow rate by 50%, everything else remains unchanged.
This function is proving useful again this year. It was already standard with the supplier back then.
HausiKlausi schrieb:
why spend so much extra on air conditioning (=treating symptoms) instead of improving the energy efficiency standard even further and also ensuring adequate shading / planting and trees outside / minimal hard surfacesAt some point, even the best KFW-type building reaches its limit in keeping heat out. A skilled architect, however, genuinely considers shading and optimal design.
G
gregman2224 Jul 2022 23:07HausiKlausi schrieb:
No offense (I don’t know the project details). But what I don’t understand: For such a large-scale project with apparently solid financial backing, why invest so much in air conditioning (treating the symptoms) instead of pushing the energy efficiency standard even higher and ensuring sufficient external shading, landscaping with trees, and minimal hardscape? These approaches aren’t mutually exclusive, and air conditioning can still be used. However, my priorities would be different. Have you really explored all options in this regard? Your reasoning makes perfect sense to me. Certainly, I have not yet exhausted all external factors that can influence air conditioning.
However, I also agree with driver55’s comment. I don’t believe that an excellent KfW-standard building guarantees effective cooling. When temperatures stay above 30°C (86°F) for weeks, even the best shading and insulation can struggle. To me, “a few degrees below outside temperature” is not reliable enough. Especially since cooling with a heat pump has physical limits. With an air conditioner, I can cool as much as I want (though it’s not as sustainable).
Of course, my goal remains to only operate the air conditioner when necessary and to support it with other methods like shading.
Unfortunately, I am particularly sensitive about indoor climate control in houses and now that I can create the infrastructure relatively affordably, I don’t want to miss this opportunity.
driver55 schrieb:
At some point, even the best KfW–whatever building can’t keep the heat out.
A skilled architect certainly considers shading and optimal design. driver55 schrieb:
Probably closer to a good 3. It has been running continuously for over 3 weeks now. At first set to 20°C (68°F)… then 19°C (66°F), and for more than a week now at 18°C (64°F) supply temperature.
In the bathroom, I reduced the flow rate by 50%, everything else remains the same.
This function is worth it again this year. It was already standard with the provider back then. Do you have a basement? I’m a bit concerned about possibly shifting the dew point there due to the cooling, or condensate forming that could end up, for example, in the insulation or screed… Without a basement, I would do it immediately…
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