ᐅ Newly built apartment (KfW-55 standard) cannot be cooled below at least 25 °C.
Created on: 21 Aug 2022 08:52
F
Forsberg21
Hello,
I have rented out a new apartment (built in 2021, KfW-55 standard). The tenant recently informed me that since spring, the indoor temperatures have consistently been at least 25°C (77°F) or higher. On warm days, it even reaches up to 28°C (82°F), although she keeps all the aluminum shutters closed during the day (no home office). Cross-ventilation at night doesn’t bring the temperature below 25°C (77°F). She is asking for advice on how to cool the apartment down a bit during the summer.
What could be causing this?
The apartment has a decentralized ventilation system and underfloor heating, which is naturally turned off in summer.
The apartment faces southwest and has large window areas.
Could it be that the ventilation system continuously brings in warm outside air on hot days, causing the temperature to rise so much?
Should the ventilation system be turned off during the day?
But why doesn’t the apartment cool down at night, even though there seems to be cross-ventilation and the nights are cooler?
Do you have any tips? I am a bit overwhelmed.
Best regards,
Robert
I have rented out a new apartment (built in 2021, KfW-55 standard). The tenant recently informed me that since spring, the indoor temperatures have consistently been at least 25°C (77°F) or higher. On warm days, it even reaches up to 28°C (82°F), although she keeps all the aluminum shutters closed during the day (no home office). Cross-ventilation at night doesn’t bring the temperature below 25°C (77°F). She is asking for advice on how to cool the apartment down a bit during the summer.
What could be causing this?
The apartment has a decentralized ventilation system and underfloor heating, which is naturally turned off in summer.
The apartment faces southwest and has large window areas.
Could it be that the ventilation system continuously brings in warm outside air on hot days, causing the temperature to rise so much?
Should the ventilation system be turned off during the day?
But why doesn’t the apartment cool down at night, even though there seems to be cross-ventilation and the nights are cooler?
Do you have any tips? I am a bit overwhelmed.
Best regards,
Robert
B
Benutzer 100127 Aug 2022 07:17Nutshell schrieb:
56 kWh over an effective 24 days (we were away for 2 days).
Cost: 2.33 kWh/day = €0.70/day. What kind of split air conditioning system is this? Because 56 kWh is very, very low if it actually ran for 12 hours a day.
By the way, I found the temperatures inside the house this year to be the most comfortable.
We consistently kept the east side closed, hung a large sail (about 6 meters (20 feet)) on the south side, and in the evening, the west side blinds are lowered.
What I think was different this year compared to previous years is that it cooled down much more intensely outside at night.
By the way, yesterday was the first day of rain in three months, except for one day. How do I know this so precisely? I cycled to work every day.
Panasonic 6.8 kW outdoor unit
3 × 2.0 kW and 1 × 3.5 kW indoor units Etherea
Strangely, it has a relatively high standby power consumption of about 240 watts per day, which I noticed when I was away. The indoor units listen via Wi-Fi and are accessible through the cloud, which might explain it. That’s 2.5 watts per unit, which seems plausible. Still, it adds up to a lot over the year: 87.6 kWh.
This also means that the 56 kWh consumption includes 5.8 kWh of standby energy.
3 × 2.0 kW and 1 × 3.5 kW indoor units Etherea
Strangely, it has a relatively high standby power consumption of about 240 watts per day, which I noticed when I was away. The indoor units listen via Wi-Fi and are accessible through the cloud, which might explain it. That’s 2.5 watts per unit, which seems plausible. Still, it adds up to a lot over the year: 87.6 kWh.
This also means that the 56 kWh consumption includes 5.8 kWh of standby energy.
Georgian2019 schrieb:
KfW70 with a solid 36.5cm (14 inches) wall and double-glazed windows: the indoor temperature is consistently around 23 degrees Celsius (73°F). When it was frequently above 30 degrees Celsius (86°F) outside, the living room sometimes reached 25 degrees Celsius (77°F) because the patio door was often left open. Otherwise, at night at least one window is tilted open, and early in the morning with temperatures around 17-19 degrees Celsius (63-66°F), the house is ventilated. During the day, shutters on the south and west sides remain closed.
I know why I didn’t build a KfW55 or 40... basically a plastic house with a ventilation system. I have a KfW55 monolithic build—is that basically a plastic bag?
We also built a KFW 55 house (without subsidies) and have not experienced such problems; the maximum temperature inside has been about 24°C (75°F).
We chose not to install a ventilation system, but thanks to intelligent shading and only opening the windows at night, we do not have excessively high temperatures either in the attic or on the ground floor.
The photovoltaic system on the roof also protects the roof tiles from direct sunlight, which provides additional cooling.
We chose not to install a ventilation system, but thanks to intelligent shading and only opening the windows at night, we do not have excessively high temperatures either in the attic or on the ground floor.
The photovoltaic system on the roof also protects the roof tiles from direct sunlight, which provides additional cooling.
Nutshell schrieb:
Panasonic 6.8 kW outdoor unit
3× 2.0 kW and 1× 3.5 kW indoor units Etherea
Strangely, it has a rather high standby consumption of about 240 watts per day, which I noticed when I was away. The indoor units listen via Wi-Fi and are accessible through the cloud, maybe that's why. That’s about 2.5 watts per device, which seems plausible. Still, that adds up over the year: 87.6 kWh.
This means that in the 56 kWh consumption, 5.8 kWh are standby power. Please do the math properly… (no one can follow that)
And when I read
Nutshell schrieb:
consumption of about 240 watts per day I start doubting all the numbers.
What was running for 12 hours a day and for how many days? What is the power consumption of the devices?
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