UPDATED: Air Source Heat Pumps/Air Con - Full Info & Guide, is it cheaper to run than mains gas?

richardc1983

rhubarbe wrote: »

Ecodan is Mitsubishi Electric ASHP. This is fairly new technology and review sites tend to spring up in areas where they get high page impressions and hence advertising revenues. No such thing as a free lunch, as they say. From my experience I think you should look at Mitsubishi, Sanyo and Daikin..

Mitsubishi, Sanyo or Daikin are the market leaders and are well respected companies.

You wont go far wrong with them.

bushyh

Well we are snowed in and the Calorex man and installer are snowed out so we wo't be getting any warmer until a week Thursday - getting used to it now.

rhubarbe

What happens if you just leave it on all the time?

richardc1983

rhubarbe wrote: »

What happens if you just leave it on all the time?

Yeh I agree I would leave it on 24/7 until they have been out.

bushyh

When I left it on 24/7 it didn't make much difference so figured probably wasn't worth the extra energy - I was hoping to paste the results of records I have taken but it doesn't cut and paste well sufficient to say therefore that on most days at 7.30am after coming on at 5am hall is about 14C and lounge slightly higher (radiator on full in lounge wall thermostat in hall at about 23) at 9 in the evening the results are about 17C one day we nearly made it to 18. Today at 12.10 we are at 14.9C. When I left it on all day it actually didn't make any difference it was maybe 1 degree warmer in the morning and that is how it stayed.

Currently we are at 14.9

This is what I have been told by an aquaintance who is not involved but it is useful information.

7.86kw hot water heat output at 55 degrees for the unit you have at the current air temperature. So, one small 2' x 2' single radiator uses 0.5kw that only leaves 7.36kw spare. An average size radiator uses 1 kw. You have 14 radiators and 3 towel rails, probably all different sizes. The maths aren't good. You would need two of the units you currently have to heat the house efficiently. You should have double radiators because of the lower temperatures put out by the heat pump (ie. 55 degrees) and a radiator runs efficiently at 60+ degrees. Air source heat pumps do not work in extreme low temperatures so you need a supplementary heating system in place for back up (ie an inline electric boiler)

So when they eventually turn up should I expect to have a backup system installed, a gas boiler as well as or instead, a more powerful pump or do I hope something else with the installation is wrong. If an additional or more powerful pump is installed how will that impact the electricity bill and would gas then be more economical

richardc1983

bushyh wrote: »

7.86kw hot water heat output at 55 degrees for the unit you have at the current air temperature. So, one small 2' x 2' single radiator uses 0.5kw that only leaves 7.36kw spare. An average size radiator uses 1 kw. You have 14 radiators and 3 towel rails, probably all different sizes. The maths aren't good. You would need two of the units you currently have to heat the house efficiently. You should have double radiators because of the lower temperatures put out by the heat pump (ie. 55 degrees) and a radiator runs efficiently at 60+ degrees. Air source heat pumps do not work in extreme low temperatures so you need a supplementary heating system in place for back up (ie an inline electric boiler)

Agree with most of this but regarding the supplementary heating system. If you have a decent make system these will work down to -15C.

My air to air heat pump has the house at 22C now and its -3C outside and no loss of performance its working a treat.

Your radiators if they are all singles then you should have doubles this is why you are cold and the house isnt warming up. IF you never upgraded the radiators when you had the system fitted then you are still sized to have a gas boiler which runs at about 80C flow temp in this sort of weather, the fact you are running it at 55C is the reason you are not getting any heat.

SO to me the radiators are not correct and the actual heat pump itself may not be big enough for your requirements.

THey havent done the heat load requirements properly. YOu want to be ringing them and seriously kicking off.

rhubarbe

I can't really help you much on this except to say that we have only 8 radiators, two only are double and these are all 20 years old, apart from one new one in the kitchen that is cold at the bottom due to sludge (being cleaned on 10th Dec). At present our heat pump isn't heating our house but then it was -11°C last night and I knew when we bought it that it wouldn't cope at those temperatures. The suggestion of an in-line electric boiler is a good one, these are even relatively cheap to buy but my goodness do they cost a packet to run, unless you are on Economy 7...

We have electric underfloor mats at the back (northern) end of the house and the kitchen one has been on now for three days so we are warm again. I am hoping that once the kitchen radiator is working properly we can dispense with the EFH again.

Our radiators in the rest of the house are perfectly adequately warmed by the 8.5kW heat pump, in fact we can get too warm. We used to have a coal fire every night but now we don't bother.

If you could post your temperature readings in a table it would help to decipher them..

bushyh

Thanks for your comments, the house is actually brand new and this is the system installed from the outset. The hall and landing has single radiators, the others are all double with the exception of the main bedroom which is single but twice the length for some reason. The calorex brochure does say that a supplementary form of heating shouldn't be needed. Guess I will just have to wait until they turn up next Thursday and hope that the reason for it not working is very simple and easily fixed.

rhubarbe

Where's the thermostat and what's it set at ??

richardc1983

bushyh wrote: »

Thanks for your comments, the house is actually brand new and this is the system installed from the outset. The hall and landing has single radiators, the others are all double with the exception of the main bedroom which is single but twice the length for some reason. The calorex brochure does say that a supplementary form of heating shouldn't be needed. Guess I will just have to wait until they turn up next Thursday and hope that the reason for it not working is very simple and easily fixed.

Are your radiators getting hot?