ᐅ Underfloor heating with an air-to-water heat pump. House gets too warm when the sun is shining.

Created on: 4 Dec 2019 14:18
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chewbacca123
Hello everyone,

I have a general question.

We moved into our new build four months ago. The living area on the ground floor has three large floor-to-ceiling windows facing south. We have underfloor heating and an air-to-water heat pump.
It provides a really comfortable temperature inside the house, but we have a problem – whenever the sun is shining in winter, even if it’s -2°C (28°F) outside, the temperature suddenly rises to 24°C (75°F) in the living room. It gets uncomfortably warm in here, and the underfloor heating can’t be turned down quickly.
Should we assume that the large floor-to-ceiling windows are responsible for the heat gain? A photo of the south-facing side of the house is attached.
What would you do – always lower all the blinds as soon as sunlight is forecast? That seems quite annoying...
We have motorized blinds controlled by Somfy. Would you consider buying a sensor that automatically lowers the blinds at a certain temperature?

Thanks in advance for your replies.

Neues zweistöckiges Haus auf Baustelle mit weißer Blockfassade, pinker Dämmung und großen Fenstern
blackm8824 Jan 2020 06:07
We are currently at -6 AT, with a supply temperature of 28.1°C (83°F) and a return temperature of 26.0°C (79°F).
B
Bookstar
24 Jan 2020 07:50
blackm88 schrieb:

We are currently at -6°C (21°F) outside temperature, with a flow temperature of 28.1°C (83°F) and a return temperature of 26.0°C (79°F).
What kind of advanced heating system or insulation do you have? Sounds like a log cabin?
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guckuck2
24 Jan 2020 07:54
Bookstar schrieb:

What kind of advanced heating system or insulation do you have? Sounds like a log cabin?

The system will be designed for a 30°C (86°F) supply temperature, with correspondingly close pipe spacing. That fits perfectly.
Our heating curve ends at 28°C (82°F) return temperature, which corresponds to about 30°C (86°F) supply temperature.
H
halmi
24 Jan 2020 07:55
We had about -7°C (19°F) outside, with a flow temperature of approximately 29.4°C (85°F) and a return temperature of 25.4°C (78°F) in a KFW55 concrete house.
B
Bookstar
24 Jan 2020 11:49
Then you have probably installed many more pipes; we have stuck to about 10cm (5 inches). That's likely why we have a higher flow temperature, otherwise the house would be too cold.
blackm8824 Jan 2020 12:21
Bookstar schrieb:

What kind of advanced heating system or insulation do you have? Sounds like a log cabin?

KfW55 house, timber frame construction ... wall with installation cavity, 20cm (8 inches) wood with wood fiber insulation, and then an additional 12cm (5 inches) wood fiber insulation on the outside ...