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
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Lumpi_LE
23 Jan 2020 10:09
Heating curves are set slightly differently for each device, so 28 22 0 doesn’t say much on its own... In your case, it seems the values mean you have a flow temperature of 28°C (82°F) at 18°C (64°F) outdoor temperature and 40°C (104°F) at -12°C (10°F). That is quite high.
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Hans-Maulwurf
23 Jan 2020 10:11
Lumpi_LE schrieb:

Heating curves are set differently on each device, so 28 22 0 doesn’t say much...
In your case, the values seem to mean that at 18°C (64°F) you have a flow temperature of 28°C (82°F), and at -12°C (10°F) it’s 40°C (104°F). That’s quite high.


What values would be considered normal?
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Lumpi_LE
23 Jan 2020 10:13
It depends on the house and the energy consumption.
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Hans-Maulwurf
23 Jan 2020 10:21
Lumpi_LE schrieb:

It depends on the house and the energy consumption.
The house is a new build, 170 sqm (1830 sq ft) with underfloor heating, and I don’t know the energy consumption yet since we just moved in this week.
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halmi
23 Jan 2020 10:40
The data should be included in your energy performance certificate.
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Daniel-Sp
23 Jan 2020 10:43
The data in the energy performance certificate do not provide any reliable information about the actual heating load...