Finally got one installed & it is toasty.
The big question is,
leave it on low all the time
or
turn it on & off as needed.
We’ve been told the former, but I think it will chew up power & waste heat. I don’t have any figures I can work out energy consumption with. Trouble is, the Mrs believes what her mother tells her, who was told by someone at work.
I reckon use when it’s needed.

Yeah getting advice from someone at your mother-in-laws work is just daft – advice from an anonymous muppet on an internet forum is far more credible 😉

I thought you were supposed to keep them on. The other thing to consider is that it needs to do a hot cycle every few days to kill off the nasties in the system which can cause things like legionnaire’s disease.

Yes , well, the Muppets usually make themselves known early on.
Now perhaps someone with some useful insight will voice an opinion.
Thank you.

Unless it requires running all the time for reasons of self-maintenance (manual should tell you) then turn it off when you’re not there or you’re just binning energy?

Manual doesn’t mention any self-maintenance. You have to clean the filters yourself.

Running any heating system on all time always uses more energy than allowing the temperature to fluctuate by turning it off. Average temp is lower, so less wasted energy. – Why should there be any question at all?

“I don’t have any figures I can work out energy consumption with.”.. You do have an electricity meter, monitor that for a few weeks.

If its a ground source pump with minimal buried pipework running it constantly throughout the year is going to give you diminishing returns dropping the soil temperature around the pipework lowering the systems efficiency. The only adjustment, beyond those stated in the manufacturer’s instructions, is that heat pumps work at a lower temperature to gas systems so you need to turn on the system earlier to account for the lag in heating response (depends on what emitters your using though)

Just an air to air heat pump. Haven’t seen a ground source one available here. Seems like a good idea though.

Most of us will already have air to air heat pumps in the form of a fridge. That switches on and off to maintain a setpoint. I would just use it when you need it to save energy. Is it possible that your mother in law is confusing underfloor heating (commonly driven off heat pump systems)? If that’s the case I would leave it on with a setback temperature increasing the setpoint when you needed a bit more.

Is it a split type AC unit? Mitsubishi or Daikin type thing?
It’s probably an Inverter driven unit and so should only run the compressor at whatever speed it needs to. Never the less, I would only turn it on when required (perhaps operate the timeclock). If you are to maintain it yourself, make sure that you clean the outdoor unit heat exchanger coil.
Craggyjim, I’m afraid you’re wrong refrigerators are cooling only and so are not heat pumps unless they have a reverse cycle defrost. Heat pumps are capable of heating and cooling by reversing the refrigeration cycle.

I’ve got a Daikin inverter one and have had it for about 2.5 years now. The guy that installed it said either approach works fine depends on your circumstances like if i had kids etc I would leave it on all the time on a constant temperature> He also said is the house is a wood frame one with as much insulation as you can put in (good roof amount, underfloor expol etc) but single skinned windows the building itself has little thermal memory (?) so you’re just heating the air all the time with very little being retained by the structure so if i whack it on a time than comes on an hour before i get home the house would feel warm. That s been my approach – 5am-6am and 6pm-8pm every day in winter, if I’m in i can override. That lot cost me approx $45 a month extra in power.

kiwijohn – can’t you just ask the guy who installed it?

I’m of the use it when you need it school. Got the timer set for morning & night, it’s a Daikin as well.
I don’t believe leaving it on would use less power. But I am open to reasonable argument. Even unreasonable argument.