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
C
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
H
hausbauer
30 Dec 2019 14:37
Better to heat one room efficiently and have the rest of the house heated inefficiently? But I’m not sure where the right compromise lies.

In terms of consumption, looking at the thermometer might provide an explanation...
chewbacca12330 Dec 2019 15:06
Hausbauer schrieb:

Better to heat one room efficiently and have the rest of the house heated inefficiently? But I’m not sure where the right balance is.

Regarding consumption, checking the thermometer might provide an explanation...
Yes, but we currently have great sunshine around midday. Still, the consumption is high?
seat8830 Dec 2019 15:20
chewbacca123 schrieb:

I have an electric towel radiator in the bathroom, but I don’t really want to use it to heat the bathroom since it consumes electricity. The underfloor heating is supposed to handle that. I’m still giving it my best shot and trying to optimize wherever I can. But if necessary, I’ll fall back on the towel radiator.
What really annoys me is that we’ve been using about 30 kWh per day for the last four days, and yesterday to today it even went up to 35. The sun has been shining strongly all the time, so I just don’t understand it. We hardly have any heating cycles left, and the hot water isn’t running 24 hours a day anymore.

That adds up to over 10,000 kWh per year... well then, cheers to that. Sorry, but that’s absolutely crazy.
H
hausbauer
30 Dec 2019 15:26
seat88 schrieb:

That’s easily over 10,000 kWh per year... Well, good luck with that. Sorry, but that’s just insane.
If you have consistent subzero temperatures overnight at home for 365 days a year, then yes...
tomtom7930 Dec 2019 15:26
@chewbacca123 Do you have a pump overrun time set on your system? What is it currently set to? It wasn’t clear to me from the CSV file. Reduce it to 5 minutes. Maybe you also need to accept that you can’t do without an electric auxiliary heater in the bathroom. It’s better to save energy on about 90% of the heating surfaces than to restrict them and end up without a warm bathroom.
seat88 schrieb:

That’s easily over 10,000 kWh per year... Well, good luck with that. Sorry, but that’s just crazy.

Well, we have “winter” now, at least 5-6 months with no heating at all. And during the other 6 months, heating is used less proportionally.
D
Daniel-Sp
30 Dec 2019 15:50
tomtom79 schrieb:

@chewbacca123 Does your system have a pump overrun time? What is it set to? It wasn’t clearly visible to me in the CSV file. Reduce it to 5 minutes.
From what I understand, the pump optimization time only applies when the outside temperature is above 1°C (34°F). Since the change yesterday evening, it has been colder. The effect will be noticeable on warmer days.
It is now set to 5 minutes; I’ve seen the current CSV file.