View Full Version : Can I set a heat pump to a low temperature?

31-01-2014, 12:20 AM
I currently only have wood heat in my home, and would like a backup to use when I go away. I don't need the house to be that warm - just 12C or so. I was told that heat pumps should be set to at least 18C or else their defrost cycle would not work. Could someone please confirm this is true, and explain how this works?

31-01-2014, 09:01 AM
It is the indoor room/house thermostat you would set at 12C, not the flow temperature of the heating circuit.

You would need to input sufficient energy into the heating circuit to overcome the heat losses through the building fabric, when the outdoor temperature is less than the required indoor temperature.

31-01-2014, 12:16 PM
The Fujitsu I have in my shop is set to 15c and it defrosts very well, thank you.

31-01-2014, 10:47 PM
Many of the air source heat pumps that I look after have a setting on the programmable thermostat that sets the room temperature at 12degC by default and then returns to the next programmed set temperature when required.
If the room temperature is set at 12degC, then the heat pump will not have too much work to do to maintain that temperature and will therefore not need to go into the defrost mode as frequently.

install monkey
31-01-2014, 11:17 PM
my daikin ux1 wall mount can be set to 10 deg heat to keep me conservatory dry.
adaikin with a hard wired brc controller can be set for home leave to maintain 10 deg frost protection, also sanyo's and mitsi heavy have similar functions

Gideon Beddows
11-02-2014, 03:56 PM
Have you considered Mitsubishi's 'Ecodan'? Its a heat pump that can run hot water through radiators? Its not as cheap as gas, but its cheaper to run than electric or oil? Search the tinter for 'ECODAN' ?

12-02-2014, 11:12 AM
Still Not sold here......AFAIK

28-03-2014, 12:20 PM
Defrost cycle usually is controlled by ambient and pressure in the system.
You can set your indoor temp to anything you like.
lowest return temp on hp will depend on model

28-03-2014, 02:39 PM
Still Not sold here......AFAIK


24-04-2014, 08:19 AM

As my opinion, there is disagreement on this issue. I would not lower than 15-16 C or 60 degree fah.