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

albyota

bushyh wrote: »

The bank pulled the plug on the builder ( unecessarily so if they knew the area and their business - which I do - both) and I think that hasn't helped in any of this. I bought off plan way before all of that and had to wait 2 years for it to be built - location, size and re-negotiated price were perfect which is why I stayed the course. Is it worth looking at a bivalent installation or do you think I should give up the idea of the pump. there's a part of me that is thinking what if it really is cheaper to run the pump over a milder winter. Thanks you all of you for your views, I appreciate I have been hogging the site for a couple of weeks but I think am now at decision making mode and ready to make the call tomorrow.

If the builder can change the heat pump for a 'proper one'...fine, if the house has been built to a good standard and the radiators have been sized correctly then a decent heat pump would be the better option in the long run, especially for the RHI, Bivalent may be the better solution for the builder as it will be at a lower cost to him. I'm not sure how the RHI will be applied to Bivalent systems.

For the next couple of years....? mains gas is going to be lower on running costs, but no RHI, a few years from now....a different story. I wouldn't mind betting that the gas boiler they fit will probably break down in five or so years......a perfect opportunity to look again at ASHP's, the cost should come down.

richardc1983

Cardew wrote: »

It is illegal for a landlord to charge more than he pays for electricity.

I know so who do I speak to, the electric board are not interested.

richardc1983

Cardew wrote: »

This thread is full of posts that seems to think that getting a house to 22C with an ASHP is an great achievment.

I can get it higher if I want to, I am pointing out 22C in my post as this is a good target temp for these temps.

WIth it being the weekend my landlord has the central heating on all day long. We have massive double radiators in every room and the boiler is set on max at about 80C and radiators are scalding to touch.

The house got down to 11C during the night. The heating comes on at 9am on a weekend and by 3.30pm this afternoon it had only got the house upto 20C. If I was to use the heat pump I would have hit 22C by about midday.

So for me my heat pump gets the rooms upto temp quicker in my flat quicker than the central heating and has used less energy in doing so.

This house is so poorly insulated it loses heat so quickly. Last night we bumped it upto 23C and we was too warm after an hour or so, we put it down to 21C and the house dropped to 21C in the space of 15minutes.

richardc1983

rhiwfield wrote: »

Some advice please.

I'm thinking of replacing the base load (60-70%) of my oil CH with an ASHP (difficult site, no room for drilling). Purpose is to further reduce reliance on oil and take advantage of RHI if applicable. I would also expect it to be currently a bit cheaper than oil, much cheaper in long run.

1970's 2-storey house is about 2,300 sq ft, 17 windows all double glazed, cavity wall insulation and 250mm loft insulation. Currently using about 1500 litres of oil pa + 7 cu m of logs for woodburner in lounge/diner. Concrete floors, standard rads, most installed before improved insulation and glazing so prob oversized for current heat loss.

Boiler is WB non-condensing danesmoor utility 20/25 (22.5 kW, only 3 years old, Sedbuk 84% efficient and said to be very reliable) and a newish self bunded oil tank. I'd guess the max heat requirement is currently about 16kW, maybe less.

Am expecting quotes shortly for a bivalent system, probably ASHP for space heating only (not DHW) as all appliances are cold fill and we use electric showers.

As I understand it the oil CH will be retained and take over from the ASHP in very cold weather.

Any comments welcome but in particular:

• will there need to be an additional water tank
• is the ashp heated water kept separate from DHW
• is their any real risk of bacteria build up in existing tank or any new tank
• how do the twin systems work when the equilibrium point is reached
• what ASHP maintenance is required
• what is likely cost ballpark
• can I use oil boiler to heat hot water separate from ASHP

Thanks in advance.

If your are just wanting to supplement the oil system easiest setup would be to install air conditioning units in each room that you require heating (you benefit from coolign in the summer too this way).

richardc1983

bushyh wrote: »

Firstly I should confirm that Bushy is a she not a he! My house is about 1800 sq ft. Last night I turned the thermostat down to 18 and left heat on - turned my bedroom radiator off (don't like the heat at night). This morning the temperature was 15 in the hall and 15.5 in the lounge compared to 13.4 and 13.5 the previous day when I had it off overnight. (Don't have an outside temperature). I turned the thermostat up to 22 at 7.30 am. It is now 11.30am and hall is 15.5 lounge 16.5. My electricity usage yesterday was 112 units (this includes everything - no washing or tumbledrying done but lights, TV computers etc). My electric bill for the last 26 days would come to £226! Tomorrow I will be phoning the builder again to say I feel I have done enouogh experimenting and that the pump isn't fit for purpose.

I agree get them told. 2 options to install a larger heat pump by a decent manufacturer, Daikin, sanyo, mitsubishi, etc or to remove it completly and fit you a gas boiler if there is gas to the property. You are spending a fortune on heating a house that it just cant heat. Installing a bigger unit and by a decent manufacturer will burn less electricity.

I will also suggest that you really kick off and threaten action against them if they dont resolve this. The fact you set it to 18C during the night and the room temps still continued to drop and it didnt rise probably is down to the fact that you are in bed and there is no heat being created by lights/tvs cooking etc and body heat.

The system isnt able to cope at all. A house your size has enough with 14kw heating however your unit cannot work at low outdoor temperatures.

Did you find out what temperature hot water it is producing. How hot are the pipes outside at the unit, did they measure them?

richardc1983

bushyh wrote: »

Alby. I will be careful not to tar all with the same brush as you say - I suspect the calorex one is probably cheaper than the others and that's how I ended up with it! At this stage I think I have to suggest that they replace the system with a gas boiler, on the basis I am worried that if I suggest a different pump and that doesn't work I'm in trouble whereas if they go for the gas then at least I know it will work.

I can promise you if they install a daikin, mitsubisi, sanyo, samsung system it WILL be able to cope when the temp drops below 5C.

As you stated the house was warm when it got mild last week.

bushyh

richardc1983 wrote: »

I agree get them told. 2 options to install a larger heat pump by a decent manufacturer, Daikin, sanyo, mitsubishi, etc or to remove it completly and fit you a gas boiler if there is gas to the property. You are spending a fortune on heating a house that it just cant heat. Installing a bigger unit and by a decent manufacturer will burn less electricity.

I will also suggest that you really kick off and threaten action against them if they dont resolve this. The fact you set it to 18C during the night and the room temps still continued to drop and it didnt rise probably is down to the fact that you are in bed and there is no heat being created by lights/tvs cooking etc and body heat.

The system isnt able to cope at all. A house your size has enough with 14kw heating however your unit cannot work at low outdoor temperatures.

Did you find out what temperature hot water it is producing. How hot are the pipes outside at the unit, did they measure them?

I asked if the pipes were supposed to be hot and the tehinical guy said warm not hot so that was the end of that.

richardc1983

bushyh wrote: »

I asked if the pipes were supposed to be hot and the tehinical guy said warm not hot so that was the end of that.

What I mean is the pipes should be at the same tem as the flow temp that you have asked the system to produce on the controller.

So if you have it set at 40C on the controller then the radiators should be at 40C etc etc. You can tell this if you feel the pipes coming from the mixing plenum inside your house. These pipes should be at the temp selectred on the controller

Cardew

richardc1983 wrote: »

I know so who do I speak to, the electric board are not interested.

Trading Standards Office will be a good start.

richardc1983

Cardew wrote: »

Trading Standards Office will be a good start.

Thank you I will speak to them.