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

danrv

Jeanbuchan said:

Be very careful before you choose an air to air heat pump.  We installed one in 2013 at a cost of £9,500.  We thought it was a good buy and it was definitely a lot cheaper to run than our old storage heaters.  Five years later it stopped working and the company went into liquidation.  As we had paid in full at the time of purchase, that was it for us, even though it was guaranteed for ten years.  We had to have a specialist come to extract the units because of the gas. 

Thanks. Sorry to hear the problems.
I’m waiting for a quote and system details but would like a Mitsubishi heatpump. The proposed position would be on a side wall/garage roof and exposed to the elements.
My only other heating option is 3 or 4 Quantum storage heaters and a couple of electric rads which would be near enough maintenance free. 

Jeanbuchan

It was Hitachi.  I did get someone to look at it and he said it needed a new expensive part, sorry, I can't remember what it was.  What is the part called that regulates the temperature?  The company was Superseal and they, at that time, were a reputable firm.  We live in north Scotland and there were no
 suitable companies available in this area.  At the time we bought it there was little understanding about these pumps.  I did a lot of online research and even contacted the Energy Saving Trust(Scotland) but got little help from them at that time.  

Reed_Richards

Any long-term guarantee from an installer should be backed-up by an insurance policy.

hebridean

I installed a 11kw Grant Aerona in a new build nine years ago which has performed really well apart from me now being on my third soft starter. They sell for around two hundred pound and Grant seems to be the only place they can be sourced, from Malta no doubt were they are manufactured. My question is would it be ok to use another manufacturers soft start assuming it met the same voltage amps watts etc?

matelodave

What odes the "soft start" consist of - is it a standard off the shelf item or specific to the Grant Aerona heat pump.

It's not easy for any of us to guess what or how this device works in conjunction with your specific heatpump. Trawling the web seems to show that a "soft start unit" could cost anything up to £450 or more so you'd need to be pretty specific about what you are looking for to get a suitable replacement.

My heat pump is inverter driven and so doesn't have a soft start device

hebridean

Yes matelodave I suspect it could be made for grant in Malta. The info on the unit is a bit sketchy and not what I would want to base a purchase on. I think my best option would be to approach one of these specialists selling soft starters with this image, and see what they can come up with. 

matelodave

These look about as close as I can find, but TBH they dont look to be any cheaper than if you buy it from Grant - I cant find the exact part number but it looks like a Carlo Gavazzi soft starter (both physically and the part numbers look similar) - you may find that the Grant unit is specially made for Grant by CG to suit a specific compressor.*

https://www.parkelect.com/en/Carlo-Gavazzi-RSBS2332A2V12C24HP-Soft-Starter/m-1577.aspx?gclid=Cj0KCQjw8vqGBhC_ARIsADMSd1C5hR1mXzOirUCbSMKfr4NbaFs3oPX6TEwJvizYivO16sOebvciP9EaAo-nEALw_wcB

and if you trawl t'interweb for long enough you can find all this and more = http://www.productselection.net/PDF/UK/mc_rsbs.pdf

* I had a problem with the flow switch on my Daikin ASHP who want around £180 for a replacement. There doesn't seem to be an off the shelf unit with the same parameters (although I could probably get away with the nearest equivalent for aroun £70). 

I was lucky, it was just some crud in the paddle which once cleaned sorted the problem without even getting a little man in.

hebridean

Many thanks Matelodave for your comprehensive reply and you certainly seem to have found Grants source. I noticed the made in Malta giveaway on one of the images. Like you said there’s little or no price difference to be had between then, so I’ll keep searching the bay for replacements. The one that’s presently in it came from there, used for sixty quid and I expected it to fail last winter  but it’s still doing it’s thing.
That was a good call with your Daikin, and it’s very satisfying managing to fix something for little or no outlay. Having to call out someone or putting my car to the garage is the last straw. Unless I can’t be bothered😀

TN1984

Anyone have any knowledge / experience of the Daikin High Temperature Heat Pump? On paper it sounds quite appealing as it can heat similar temperature as my oil boiler that needs replacing, so would not require me to change existing radiators. There does not seem to be much information around though since most articles and guides are written in respect of low temperature heat pumps and needing larger radiators/underfloor heating etc.

Cardew

TN1984 said:

Anyone have any knowledge / experience of the Daikin High Temperature Heat Pump? On paper it sounds quite appealing as it can heat similar temperature as my oil boiler that needs replacing, so would not require me to change existing radiators. There does not seem to be much information around though since most articles and guides are written in respect of low temperature heat pumps and needing larger radiators/underfloor heating etc.

The Daikin Brochure gives some information on installation prices, servicing costs, and their version of running costs. However no technical data i.e COP with water at X degrees with ambient temperature Y degrees.

It is important to note that the basic principles of an ASHP operation still applies to the High Temperature heat pump i.e the higher the water temperature the lower the efficiency of the heat pump.

In the Brochure they give the comparative fuel costs for a 4 bed house. The low temperature heat pump has annual running costs of £571, the high temperature heat pump has an annual running cost of £978 i.e.71% higher.

This is based on a low electricity price of 12p/kWh and a space heating requirement of 21,600kWh. So if my maths is correct the low temp HP uses 4,758kWh to produce 21,600kWh a remarkable COP of 4.54!!!

They don't give the Hot Water consumption as, presumably the low COP for HW will spoil their figures.

To make the comparison with gas look better they prices gas at a very high 4.3p/kWh

In addition to the higher running costs the high temperature HP costs £1,559.00 more than the low pressure HP. Fitted cost for the high temp HP is given as £12,795.00.

They have 3 annual maintenance packages ranging from £138 to £336

I am sure that the brochure doesn't breach the Advertising Standard Authorities guideline!! However a non-techchnical potential customer could be forgiven in thinking an ASHP is cheaper than Gas CH - and it ain't!