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

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

Daniel-Sp21 Dec 2019 20:35

#259

Maybe you can also find the data in the energy performance certificate

chewbacca12321 Dec 2019 22:07

#260

Daniel-Sp schrieb:

Maybe you can also find the data in the energy performance certificate

Ok, I’ll check that first thing tomorrow.

chewbacca12322 Dec 2019 08:25

#261

Daniel-Sp schrieb:

For an estimation, you need
Ht, envelope surface area, heated gross volume, desired temperatures, standard outdoor temperature, number of occupants.
You can find these, for example, in the KfW certificate.
This will give you a good estimate.

This morning’s data, temperatures are already better, living area now 21.5°C (71°F) instead of 20.9°C (70°F).
But the bathroom is still only 20.8°C (69°F), which is crazy. We gave it so much more volume :-/
Hallway still 22.8°C (73°F). Radiator is: 29.5°C (85°F) - 22.0°C (72°F) - 0 (I had increased the supply temperature by 0.5°C (0.9°F))

Table with digital signals, impulses, active values as well as input and output metrics

Time series with many short blue bars over two days (VD1).

Table of heating and domestic hot water operating times with start, mode, duration and temperatures

Daniel-Sp22 Dec 2019 08:45

#262

I still firmly believe that the bathroom is undersupplied by the underfloor heating :-(
What is the setting for the hot water hysteresis?
I still find the heating cycles a bit too frequent...

chewbacca12322 Dec 2019 09:20

#263

Daniel-Sp schrieb:
I still firmly believe that the bathroom is undersupplied with underfloor heating :-( What is the setting for the hot water hysteresis? I still think there are a bit too many heating cycles...

The hot water hysteresis is set to 6. Yeah, it's a bit of a pain; somehow I’m hesitant to adjust the pressure relief valve.

chewbacca12322 Dec 2019 09:56

#264

Daniel-Sp schrieb:

I still firmly believe that the bathroom is undersupplied with underfloor heating :-(
What is the hot water hysteresis set to?
I still find the number of heating cycles a bit high...

My power consumption also continues at 20 kWh per day :-/

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

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