ᐅ Air-to-water heat pump very loud

Created on: 6 Jan 2017 16:40
H
HilfeHilfe
Hello,

Behind our two-family house is the air-to-water heat pump. Our new neighbors (three-family house) are very nice. The neighbors living on the ground floor are experiencing their first winter in the new building and hear the air-to-water heat pump running at full capacity.

They find it quite loud, especially in the evening when it operates at subzero temperatures (understandable since the house is being heated).

The heating engineer said that the air-to-water heat pump can be "turned down" during the evening or night hours to reduce noise, but he advises against this because

1 - The house cools down
2 - The air-to-water heat pump risks icing up since the heating elements are also turned down

What do you think about this? Are there any acceptable decibel levels?
G
Grym
20 Jan 2017 11:02
Some manufacturers specify the COP at -7°C (19°F): it ranges between 2.8 and 3.3. This is far better than electric heating. This might be the case at -20°C (-4°F), but only for a few hours every few years.
W
world-e
20 Jan 2017 11:08
andimann schrieb:
Below -5°C (23°F) it will run purely as electric heating anyway

There are certainly air-to-water heat pumps that operate without an electric heating element down to -15°C (5°F).
andimann schrieb:
What exactly is supposed to freeze???? The refrigerant???

Since I have not read anywhere what type of heat pump it is, it could also be an outdoor unit heat pump where the supply and return water lines run outside and no refrigerant is involved. However, these pipes should be very well insulated and are also kept warm by the house’s heat.

But it is difficult to narrow down the problem here.
andimann20 Jan 2017 11:20
Yep, mathematically that’s correct—the reciprocal of the Carnot efficiency corresponds to performance numbers around 0.5 in those ranges. But why on earth does everyone then install heating rods...? 😉

Back to the topic: to the original poster, what supply temperature is your heating system running at? If it’s as low as possible, the efficiency improves significantly. Then the heating system might not have to "work" as hard.

Best regards,

Andreas
andimann20 Jan 2017 11:26
world-e schrieb:
There are indeed air-to-water heat pumps that operate without auxiliary electric heating down to -15°C (5°F).

Yes, that’s true. There are also good air-to-water heat pumps that don’t disturb your neighbors with unacceptable noise levels.

However, these tend to be more complex and cost several hundred euros more.

If your neighbors are already complaining, it’s probably not one of those...

Best regards,

Andreas
A
Alex85
20 Jan 2017 11:31
andimann schrieb:

But why the heck do they all install electric heating rods then...? 😉

For the mind filled with fear.

Why do heating engineers install 20kW gas burners in single-family homes? So that, in the most unlikely catastrophic scenarios, half the village can take a hot shower without running out of hot water. Anything else would be too unsafe.
H
HilfeHilfe
20 Jan 2017 11:48
I think 26 degrees Celsius (79°F)?