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

Cardew

JackMar wrote: »

Thanks for all the comments. We were advised in black and white that we would be saving a £1000 on our bills each year. We will be looking into sorting this out directly with Husky as they are the ones we are dealing with. This advise we are giving is for people to take careful consideration when thinking about having an ASHP fitted and that a lot of people on this forum may (and I only say may), work for companies that sell ASHP so they may have a vested interest to disagree and disrespect what people post who have clearly been conned.

Was that advice given in writing?


It is a pity you didn't do some research first - not least this thread on MSE:


https://forums.moneysavingexpert.com/discussion/2968958

lovesgshp

Jackmar:
I work with a geothermal company here in Italy, so have no vested interest in any in the UK. We would not normally recommend a ASHP/GSHP to anyone on mains gas supply, unless they insisted.
You will not make major savings, and as to rip out a year old boiler, unless on LPG. then there is no answer to that reasoning.
If you have in writing you will save £1000 p.a., then ask Husky to repay and also resolve the problem with the system.

JackMar

Yes we have it in writing and also the web site still maintains savings. If our house was small we may get some savings but its a large house which has been visited many times now by Husky and even though the system is now working our bills are higher than previously with gas. We are not going through another winter with the ASHP so will have to take some legal action. Other people have sent me personal inbox messages here as well who have experienced similar problems so we aren't alone.

lovesgshp

Just had a look on the Husky site, so interesting. The COP compared to 35C output v 50C output is quite different @ 7C. If the temperature drops even more, then it is far lower. In fact at 0C, you would be getting a COP of less than 3 @50C.
I cannot see anywhere on the site, where the savings would be £1000 per year over a conventional new gas system.

How large is your house in M2?
http://huskyheatpumps.com/costs/heat_pump_costs.html

zeupater

JackMar wrote: »

We bought a Husky Heat Pump in June 2011 for £7400 after ripping out a brand new year old Worcester Bosch Gas Boiler. We had a year of trouble with the pump not working more than it worked. They had undersized the pump initially it was a 12kw and then they uprated to a 16kw twin fan. This works after a fashion but have had to install a multi fuel burner to supplement the heating as our lounge is no where near as hot as it used to be with gas.

If its 5 degrees outside, the ASHP is on all the time and is only capable keeping it at 20 degrees. The cost of running the ASHP with 11 radiators and the ASHP set at 45 degrees runs at 7kw at 12p a kw which works at 84p an hour. Whereas our 42kw gas boiler run at 22p an hour. The heat output on the radiators was 70 degrees where as the max on the ASHP is 35.

In addition to this we have already spent £400 on coal to keep our lounge comfortable plus the cost of installing the multi fuel burner.

Before the heat pump was installed our electric bill was £1100 and for gas it was £1340 = £2440. Whereas now the first years running costs of the ASHP is electric £2430, coal and wood was £330 and gas £160 = £2920.00 which is £480 more for a colder house.

This year we will be running at the total utility bill of at least £3000.

Thankfully this year so far we haven't suffered the freezing conditions we did last year because if this ASHP goes below freezing it will cost even more money to run.

Hi

Looks horrendous, but we would really need much more information before anyone could form any form of accurate view.

My initial thoughts are based on our own energy use over the last 12months .... Electricity, Gas & Logs coming to ~£500 in total (with solar pv & thermal) in a larger than average property.

My view on this is to forget the cost of the fuel and simply compare the kWh being consumed by the two systems by comparing historical annual usage. Between 2011 and current date energy prices have probably increased by ~10%each year, so doing nothing would have resulted in the baseline £2440 increasing to around £3250, so the correct statement should be " £2920.00 which is £330 less for a colder house."

Apart from this, a starting point to look at is that you are still using £160/year on gas, yet have no gas heating, which looks like you are cooking with gas and probably paying a pretty hefty unit price & standing charge for the pleasure, but even allowing for the SC that's somewhere around 8kWh/day for cooking? ... are you sure ? ... are you on the best tariff for a low gas user ?

Coal & logs .... £330 would deliver us somewhere around the annual heating requirement of a decently insulated average sized UK property (Av UK dual fuel gas usage =16500kWh), yet this obviously only provides a small proportion of your heat load.

In cases such as these insulation and heat-pump operating temperatures are key. If the property isn't adequately insulated you'll be bleeding energy & if the radiators weren't all replaced by oversized units when the heat-pump was installed you'll probably be trying to compensate by running the system at a temperature which kills the system's efficiency. If your DHW temperature is set high (standard sized cylinder ?) then you will almost certainly be heating the water with elements at a COP of 1.0 at somewhere around 4x the cost of doing so with gas at a comparative COP of ~0.8.

Replacing GCH with a heat-pump needs a SCOP of ((£Electricity/kWh)/(£Gas/kWh)) just to break even on running costs, so somewhere around 3.0-3.5, then there's the difference on the installation capital cost & associated financing/ lost interest .... installing a HP where mains gas is available means that you need to maintain a really high average COP, probably much closer to COP5.0 than most units can achieve, just to break even within the expected design life of the unit. ...

HTH
Z

lovesgshp

Must admit Zeupater, I am confused on a few issues the OP has raised and as you say more info is needed.
The cost of running the ASHP with 11 radiators and the ASHP set at 45 degrees runs at 7kw at 12p a kw which works at 84p an hour. Whereas our 42kw gas boiler run at 22p an hour. The heat output on the radiators was 70 degrees where as the max on the ASHP is 35.
Why is the unit using 7kwh, when it is rated at 3.66 @ 7C. The 3kw immersion heater must be running constantly. The max temp output on that model is 60C, albeit with the added immersion, so cannot understand the rads only reaching 35C.
Obviously a lot more information is required, before any serious advice can be given.

Cardew

JackMar wrote: »

We were advised in black and white that we would be saving a £1000 on our bills each year.




Yes we have it in writing and also the web site still maintains savings.

I would look very carefully at the wording of the £1,000 saving claim.


I will bet you a virtual pint :beer: it says no such thing. I cannot think any firm would be so stupid.


Can you post the exact wording of the claim please.

offitmassive

Sorry to bump up this post, I also have the ecodan Mitsubishi system and having nothing but problems with it. Error code u1 shows a lot, the engineer says it because the fan thing in the garden is over heating as I'd adjusted times for the fan to start because the hot water just doesn't get hot enough. It was set at 50c, engineer adjusted it to 55c but it's not on long enough to get near that temp. He reset the times to come on 3-5am and 3-5 pm hot water , but it ain't enough. Immersion doesn't do jack. Ive read that people have different heating times and temperatures but all I want is some hot water!! I live in a very new Eco build home where it's mega insulated, no gas supply , just elec. and the manual doesn't make much sense to me, error code u1 been on a few times. And there's a constant whirring in the airing cupboard , the sound of when the fan is on, but it's not on as it's not it's scheduled time but the whirring is on 24/7

[Deleted User]

Hmmm...

A few thoughts...

If it is overheating then it sounds like it cannot dump it's heat fast enough. Likely cause could be wrong pump speed, incorrect pipe size, sharp bends in pipe work etc. It is critical the EcoDan has the correct flow rates. Off the top of my head it also requires two possible three pumps to keep the flow rate up.

Not heating hot water fast enough could be down to the above but also check the DIP switch 2-2 setting for DHW mode, COP priority or speed priority.

Looking at your timings 2 hours should be plenty as it should only take 30mins[ish] to heat the 210lt tank to 50c using speed priority mode.

Do you have a the DHW immersion boost button on the packaged cylinder for 15/30/60 mins? Is it this that is not working too?

The whirring could be the EcoDan is off [at temp] but the system is timed to be on so the pumps are still running? Incorrect wiring suspected... Pumps should start one min prior to the fan unit outside kicking in so the EcoDan is happy all is well.

What is the exact model and is it all UFH? Has it ever worked correctly?

Gotta run, cheers

offitmassive

Yeh I have the boost button , I press it, it lights up red, sometimes it heats the water, sometimes not . Not sure what you mean by the dip switch 2-2 , cop priority nor speed priority means. Sorry! The air init has model code puhz w50vha bs , has a badge saying cop 3.13 and 4.1 . Pumps are working as I'm typing but fan isn't spinning as it's not timed to come on yet . But the controller is a Mitsubishi electric. What does "is it all ufh" mean? The system is not timed to be on, but pumps are whirring in airing cupboard .