ASHP or GSHP or Solar panel

st999

So winter has come to an end and to all those people who changed their heating to ASHP, or GSHP, and who also installed solar panels.

How much lower were your gas and electricity bills compared to before you changed?

Edale

I have had a 14kw Mitsubishi Ecodan for about 3 weeks and my total weekly electricity use in those three weeks has been approx. 220 units/£18 per week. Old oil boiler was using 90 litres of oil per week at 60p per litre in addition to 120kwh of electricity, so my bills have gone from over £60 to less than £20. It is not a real comparison because the weather is milder but I am certain my bills are much lower as we used 50-60 litres of oil per week in October.

Next winter will be the true test when the weather gets colder and I will be able to compare costs year on year but so far I am certain it is cheaper.

st999

Not much bragging on here as to how much money was saved by switching from conventional heating systems.

Mankysteve

Make sure you've got your house insulated to within an inch of its life. Best windows, Plenty of loft insulation, If the building can be made really airtight use heat exchanger. The cheapest heat is heating you don't use.

grahamc2003

Edale wrote: »

I have had a 14kw Mitsubishi Ecodan for about 3 weeks and my total weekly electricity use in those three weeks has been approx. 220 units/£18 per week. .

220 units over 3 weeks costs £18pw which is £54? That's 25p/kwh! You need a different tariff!

From what I can gather, these should be pretty efficient while the ambient temperature is well above zero. When it's colder, then you start getting defrosting of the outside unit, which starts to knock down the cop and up the costs. I'd expect the Mitsubishi ones to cope quite well with a decent defrost strategy - but if the strategy isn't implemented well and ice builds up, then you could get problems. There's been some horror stories and pictures of iced up units posted somewhere on this site.

ra200

It is all good now but wait untill the weather is cold when the outdoor temp starts to fall below 7c when you really need the thing the COP drops of bad so you might be getting a COP of say 3.5 now by when it is say 1c outside you might strugle to get a COP of 1.0

Edale wrote: »

I have had a 14kw Mitsubishi Ecodan for about 3 weeks and my total weekly electricity use in those three weeks has been approx. 220 units/£18 per week. Old oil boiler was using 90 litres of oil per week at 60p per litre in addition to 120kwh of electricity, so my bills have gone from over £60 to less than £20. It is not a real comparison because the weather is milder but I am certain my bills are much lower as we used 50-60 litres of oil per week in October.

Next winter will be the true test when the weather gets colder and I will be able to compare costs year on year but so far I am certain it is cheaper.

Cardew

The difficulty is getting an objective measurement of performance.

Bost are totally subjective, and range from highly disatisfied(ra200) to happy(edale)

It is an undeniable fact that those who have bought systems are less likely to be critical than those who are in rented accomodation, or bought a house with an ASHP fitted.

ra200

See my post here from today here https://forums.moneysavingexpert.com/discussion/1464827

Cardew wrote: »

The difficulty is getting an objective measurement of performance.

Bost are totally subjective, and range from highly disatisfied(ra200) to happy(edale)

It is an undeniable fact that those who have bought systems are less likely to be critical than those who are in rented accomodation, or bought a house with an ASHP fitted.

Edale

grahamc2003 wrote: »

220 units over 3 weeks costs £18pw which is £54? That's 25p/kwh! You need a different tariff!

To be clear it is 220 units per week at 8.3p per KWH.

I agree that the real test will come in the winter, the system has operated around freezing on a couple of mornings and worked okay, without horrendous consumption. I will reserve judgement on prolonged cold periods until they happen.

Cardew: I don't spend c£10k easily but I think I have made sure the system is specified correctly and fitted by a company who know what they are doing. I don't think some of the HAs spend money with the same care.

I think anybody considering an ASHP needs to do so with extreme care and make sure they use a reputable company. There lies the problem really, why should anyone spend around twice the price of a conventional heating system when there appears to be some real horror stories out there. I did it because I was reasonably confident the system would work and cost less than oil to run but because I believed the icing on the cake would be the RHI which is now in some doubt. Without this the whole equation is probably marginal financially with some risk I have installed a technology that may not perform in extreme conditions.

I am happy so far, I reckon it will be just about make sense without the RHI but will report in due course once we have had it a while.

albyota

st999 wrote: »

So winter has come to an end and to all those people who changed their heating to ASHP, or GSHP, and who also installed solar panels.

How much lower were your gas and electricity bills compared to before you changed?

Well, year three of owning my Ecodan, all electric whole house 185m2 4 bed detached with UFH, family of four, all usual appliances / heating / hot water usage patterns. No other fuel.
with BG click energy 6 (ends June)
year 1 2009, £837
year 2 2010, £940
year 3 Jan 1st 2011 so far, 3411 kWh units, £278 ish

Prior to the heat pump, I was using oil and combined (electric bill and oil) fuel cost per year was around £1,450.

AL

I also know of around 80 other satisfied heat pump users, but most of them don't do Forums....

Cardew

Edale wrote: »

Cardew: I don't spend c£10k easily but I think I have made sure the system is specified correctly and fitted by a company who know what they are doing. I don't think some of the HAs spend money with the same care.

I think anybody considering an ASHP needs to do so with extreme care and make sure they use a reputable company. There lies the problem really, why should anyone spend around twice the price of a conventional heating system when there appears to be some real horror stories out there. I did it because I was reasonably confident the system would work

Edale,

Your posts have been objective, you clearly have investigated the merits and demerits of ASHPs.

However, with respect, you, nor anyone else, knows for certain which company 'knows what they are doing'! It is just your gut feel; no installer can demonstrate that their installations have all been a success because there is no mechanism to test their output.

You also have 'made sure that the system was specified correctly' . Well how many people have that knowledge? - and more importantly why should they have that knowledge?

Indeed it seems loads of installers don't have your knowledge!!!!!

The main lesson from the very poor results of the EST trial was that the same systems in similar circumstances had such wide variations in performance; and the involvement of the manufacturers didn't solve the problems. That is why the trial has been extended - to try and find out why these discrepancies exist.

The thrust of my argument is that people are indeed spending £10k on ASHPs and taking pot luck, with seemingly no comeback if they have bought a dud.