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

richardc1983

Andy_WSM wrote: »

I'm going to set my new stat at a cosy 23C this evening and see if I have solved the "draft" problem

Will let you know tomorrow!

23C far too hot for this time of year!!!!

I use 23C when its freezing outside and I start to feel draughts from the room when it starts to cool but the unit is still at thermostat off.

YOu mention your unit was draughty because the fans stayed on when not heating... being an inverter does it not just ramp down to minimum or is your unit oversized.

My units are oversized and ramps down but then cycles off a lot of the time unless really cold outside.

Andy_WSM

richardc1983 wrote: »

My units are oversized and ramps down but then cycles off a lot of the time unless really cold outside.

It's sized about right for the house. The problem being that the fans don't ever turn off when in heat mode, so when the compressor has gone as low as it can and eventually off the fans continue to run. - Not any more though

23C is only so I can trial it this evening, rather than wait for the cold weather! I would normally heat to 21/22C in the Winter, reducing to 18C over night and in the day when I am not home.

richardc1983

Andy_WSM wrote: »

It's sized about right for the house. The problem being that the fans don't ever turn off when in heat mode, so when the compressor has gone as low as it can and eventually off the fans continue to run. - Not any more though

23C is only so I can trial it this evening, rather than wait for the cold weather! I would normally heat to 21/22C in the Winter, reducing to 18C over night and in the day when I am not home.

Do you find that it controls precisely to that temperature. Sometimes I find the position of the remote sensor can be about 1C out. Eg set to 22C unit still heating and detecting 21C but some parts of room can be 23C.

I only ever run at low fan speed and even that is too high.

How often does your unit cycle off in an hour?

Andy_WSM

I find the temperature setting very accurate, probably because the system encourages a good air flow through the room due to the ducting, rather than circulate around one point.

Hard to know how often it cycles off as I haven't managed a season using it for heating yet. - Guess also it would depend just how cold it has got outside? It's entirely possible it won't cycle off at all if it is -10C outside, but would do so regularly if it was +10C.

I'm reasonably confident I don't have to worry about feeling cold now this Winter

richardc1983

Andy_WSM wrote: »

I find the temperature setting very accurate, probably because the system encourages a good air flow through the room due to the ducting, rather than circulate around one point.

Hard to know how often it cycles off as I haven't managed a season using it for heating yet. - Guess also it would depend just how cold it has got outside? It's entirely possible it won't cycle off at all if it is -10C outside, but would do so regularly if it was +10C.

I'm reasonably confident I don't have to worry about feeling cold now this Winter

Mine is very accurate to a degree its just because its an old house the walls are cold in winter so it picks up this temperature and thats where i get the draughts from the cold walls.

sparkie7203

sparkie7203 wrote: »

Thanks all - Ive put £5000 for heating (again - I'll be doing as much of the hard work myself to try and keep the costs down). From what you are indicating, if I shop around I should be able to do this with the money Ive got do you think ?

just giving this a little bump to see if anyone has a view on whether Ive got enough money set aside

richardc1983

sparkie7203 wrote: »

just giving this a little bump to see if anyone has a view on whether Ive got enough money set aside

I think your going to need a bit more than that.

Underfloor heating and air source heat pump?

sparkie7203

richardc1983 wrote: »

I think your going to need a bit more than that.

Underfloor heating and air source heat pump?

No, just underfoor.

In that case I think I'll have to stick to the conventional as ive already got a quote for less with oil. I appreciate that in the long run it may cost me more but as Im only staying there for 5 yrs it may be that oil is actually betta. Thanks all the same

albyota

Sladden wrote: »

Hi,

I realise that this is my first post so my credability might not be the best but anyway. I've reacently bought a smallish (50sqm) quirky flat that is more like a semi-detached bungalow. Insulation is OK, not good but could have been a lot worse. Heating is solely electrical with no gas in the flat and storage heaters are installed. Now to my point, I'm from Sweden and used to very cold weathers but nicely heated houses. The 'biggest' thing in heating for the last 10 years in Sweden has been air-to-air heat pumps and they are extremely common (think more like no oil or gas is used in Sweden, all new installations are pretty much heat pumps). I notice 2 main differences between the forums in Sweden (which are vary large with thousands of recent posts) and the discussions here. First and foremost PRICE.

Sweden is by no means a cheap country, pretty much everything is more expensive than in the UK. But, an installed Mitsubishi Electric heat pump with one internal unit is never (OK, maybe in very special circumstances) more than £2,000. Here people are talking about £4-5,000+. why is that.

Secondly, people here seem to complain that the unit is not efficient or working when it's cold, hmmm Sweden -20 degrees and my parents 170 sqm detached two story house is heated by a 5kw Mitsubishi unit with ONE internal unit on the lower ground in the stairwell, inside temperature in any room (internal doors open of course) never falls below 20 degrees. How can it differ so much in efficiency? OK, I know that we have 'space age' triple glazing as standard and everything is insulated but I've seen people installing 4 pumps with a internal unit in pretty much every room here... This is not how we use it in colder climates. And also, there seems to be a raliability issue as people are suggesting having a 'back-up' system. Why? I just say.

And after my rant, here is my question. If a buy a unit in Sweden instead (~£1,500) for a Mitsubishi and bring it here, would it be possible to find an installer for it? I'm in Greater London.

I would greatly appreciate any input/comments!

Christian

You can get an air to air heat pump (standard wall mounted Mitsubishi 2.5kW A/C) fitted for around £1,300 for a single room. above we mostly seem to be discussing both air to air (A/C) and air to water heat pumps for a complete central heating system in a 4 bedroomed house...hence the £6k to 9.5K its bound to cost a lot more than doing one room. But as fitting one would significantly reduce the running costs over oil or LPG, this has to factored in to the high capital cost/payback/and proposed RHI.

albyota

sparkie7203, if you were installing most of the plumbing yourself, you would be looking at about £5,800 for the heat pump and 180 Litre cylinder fitted, depending on how big the house is. But you should be concentrating on the insulation values, cavity walls, loft, DG, then get a heat load calc done.