Recommendations For An ASHP

[calson]

I've decided to install an ASHP in a 200m2 new build house. The house will have kingspan insulation reducing the u values by a third and underfloor heating with a woodburning stove in the lounge.
I've been looking at the Nibe Fighter 8kw and the Sanyo CO2 9kw.

Do any forum members have either of these units or know of their reputation within this market, or any other brand recommendations and where they can be bought?

Many thanks.

 

[doitall]

Haven't fitted any but I have heard good reports on the Worcester Bosch range.

I think you can get some good cash backs as well.

http://www.worcester-bosch.co.uk/homeowner/products/air-source-heat-pumps

 

[gas4you]

Mitsubishi Ecodan are supposed to be amongst the best at present

 

[ajstoneservices]

Mitsubishi Ecodan are supposed to be amongst the best at present

Second that.

 

[Norcon]

Isn't the ecodan teamed up with one of Gledhills products?
(aka - sludgebuckets)

Picked this up on a different forum......
Prefer the Daikin kit myself.

I installed a Mitsibushi Ecodan air source heat pump system last August. I have had a miserable winter.

First the system does work, heat is collected from the outside, even at sub-zero. However, the good news ends there. It is a new technology and a chose a local installer from those approved by Mitsibushi on a list they supplied. The dealer also featured in their publicity brochure and video. I am a pensioner and have no heating knowledge and had to rely on the installer, particularly with the Mitsibushi recommendation behind him.

I now appreciate how important it is that heat loss calculations are carried out on the property for a retro fit. It has become very clear in hindsight, that this was not done and that the heat pump is under size. My house is well protected with cavity wall, double glazing and well insulated loft, but the installer failed to do the basics, although I gave him all the room sizes when he surveyed the property. The heat runs through the system (assuming a correct size Ecodan) at 55 degrees, instead of around 70 for a oil/gas installation. Therefore, all radiators have to be changed to increase the surface area by about a third.

In addition to an undersized system - the warmest the lounge has got through the winter is 17, on coldest days 14 - the Ecodan comes packaged with a Gledhill tank. This has been nothing but a problem. It is difficult to program times, but more importantly we have had trouble with elements of it, including needing new printed circuit boards and being without any heating or hot water for a week while they were replaced.

My advice, is look very carefully, if it is a retro fit. Check out the installer (I thought I had since Mitsibushi featured them so strongly) and be very careful to look close at the unit which comes with the air pump. This unit drives the whole process and is the 'brains' of the system. Additionally, since it will become a sealed system under mains pressure, you have to be very sure of all joints etc in the existing system – we found this out the hard way!

Despite visits from the installer and Mitsubishi (supposedly their top man on Ecodan/Gledhill) no significant improvements have been achieved – though some tinkering with the system has gone on to very minor effect. My wife and I have suffered chest colds all winter and have been ill, we are now seriously looking at facing the cost of replacing the Ecodan with oil during the summer. We cannot have another winter like the last.

 

[gas4you]

Is that supposed to mean a Gledhill thermal store?

If so I can't see how it could possibly work when a store needs such high temp to work

Bit like fitting a GSHP to a thermal store.

 

[r.bartlett]

In all honesty ASHP's are all a bit of a con. Their efficiency plummets exactly when you need to run it the most -IE winter!

I met a guy who's house is being used as a working test for the Altherma (the distributor has keys to the boilerhouse and is in there every week tinkering) and his opinion "They juries out if it saves me money "

So if Daikins' biggest distributor can't get the system to blow the socks off their test client then there is little chance of the average install working.

I believe we need another 2 generations to get the efficiency up to acceptable levels where savings are actually made.

However in discussion with the tech guy at Kensa there is nothing on the horizon which will get us even close to that level.

BTW he has intimated that the testing is about to be standardized so that each manufacturer will only produce results according to these tests.

Then not one manufacturer will reach 4:1 in terms of efficiency

Being in the Western Isles I would suggest you go ground source

Try:
http://www.kensaengineering.com/

 

[ajstoneservices]

I was surprised to see they had chosen to use Gledhill cylinders cased torrent over Kingspan's Manco. I think the only difference between the standard Torrent and heat pump torrent is the later has a 3m2 coil for the heat pump.

 

[Norcon]

Another unhappy customer...............
Seems like there is a lot of rogues out there.

I have just built a house of 3000 square foot. It has concrete floors, insulated walls and roof, double glazing etc. We had underfloor heating installed with a 10kw PZP Air Source Heat Pump for the central heating and hot water with a 200 litre buffer tank - this was specified by the supplier who had a copy of our building plans and our SAP report. We moved in last November and have used over 31,500 kW/h of electricity at a cost of £3,500 - £500 to £600 per month during winter. The system does not cope with drops in temperature, during winter the water produced was not hot enough to have a bath in. The unit was supposedly sized for the property using the SAP calcs and it is is an HP1AW 10SE-2AG, the power input is listed as (A2/W35) - 2.5kW, the Ph is 8.9kW the COP is 3.6, Max Power Input 8kW, Max Total Power Input 11.8kW. The heating elements were on most of the time during winter and we werer struggling to keep the house warm, 21C in living areas 18 in beds. We have the CH output at 35C, the spacing of the underfloor heating pipes is 100mm to allow for lower output temperature. The supplier/installer now wants to install a gas boiler as a back up heat source rather than using the systems own electric elements. We have asked for our money back - no joy. Has anyone else had problems with these systems

 

[calson]

Many thanks for your replies chaps, horror stories and all.

Can't say that i had heard of Daikin, and i had thought of going for a ground source pump but decided to put the additional costs into the insulation.

 

[Deleted member 105431]

assuming you don't have mains gas have you considered solar hw and ufh from a lpg boiler?

 

[simond]

I'm an Ecodan installer.

They were using a Gledhill manufactured unit but since the demise of the arm of Gledhill that made such units, a new Kingspan unit has just been launched.

The transfer of heat from an ASHP into a cylinder is quite an interesting subject, and Mitsubishi technical have found that finned copper tubes give a significantly better performance than tank in tank or stainless.

Savings are very possible compared to oil or LPG; the comparison with gas is interesting and can be shown to save money. However it is important to get the insulation right and not overspec the ASHP. They are designed to run for long periods, not in bursts like fossil fuel heating.

The latest invverter driven units by Mitsu and Daikin are where it is going. Don't buy a cheaper fixed rate compressor product; they are simply not as economical.

 

[doitall]

Mitsubishi were supposed to have an amazing unit coming on the market just after I retired, I haven't any information about it as yet, so if anyone can update me it would be good.

 

[calson]

Yes it's my intention to add solar pannels at a later date and we do not have a LPG supplier on the island that i know of. So most people use oil or off peak electricity, but my wife cannot stand the smell of oil, hence the ASHP route.

I was just browsing and couldn't find a price/seller of the Ecodan/Kingspan unit. Any ideas on price?

Simond. What did you mean by: Don't buy a cheaper fixed rate compressor product; they are simply not as economical.

 

[Norcon]

but my wife cannot stand the smell of oil

Wot smell?
Unless you have a leak you will not smell oil.
A labrador might but then their noses are a lot more sensitive than a womans. (I think)