Air Source Heat Pump Reviews?

AsaMac

I can't find anything current on this so I thought I'd see if any one could advise me on Air Source Heat Pumps (ASHP). I know the new government intensive has changed the game a wee bit and, since I'm re-mortgaging, I was thinking of taking an extra bit to pay for the ASHP. I don't know anyone with a system and everyone seems to have massively conflicting views on the validity of the potential system.

I live in Devon and have a big old house (1850) with 4ft thick flint walls, new double glazing, underfloor heating downstairs and radiators upstairs. My loft is fully insulated and I already have solar PV.

I currently have an LPG system which costs me about £1200 a year, I use the hot water and heating as sparingly as possible but the house is about 190m2 so it takes a lot to heat it up.

I've had a quote from Ecovision of £9k for a Mitsubishi Ecodan 14kW and a Mitsubishi 250L Cylinder and the marketing says:

Expected annual saving compared to LPG: £600 x 20 = £12,000
Expected annual RHI payment: £853.95 x 7 = £5,977.65
Replacement cost of LPG boiler within lifespan of heat pump: £3,000
Total 20 year (lifespan of heat pump) benefit: £20,977.65

So that's a 6.5 year period to break even. Seems not bad.

Has anyone got any advice, opinions and insights?

Cardew

You are looking in the wrong section of MSE.


There are many thousands of posts in the other sub-section of energy - including this 'sticky' thread:


https://forums.moneysavingexpert.com/discussion/1464827


You should also read the Energy Saving Trust trials report(s).

matelodave

As Cardew say have a look at the other thread as there's loads of info about them and about people's experiences.
I've got one in a reasonably insulated (loft & cavity wall) 140sq.m bungalow with underfloor heating and for me it performs well and I'm getting the results I predicted. (ours was a totally new system, heating, hotwater & heatpump - so they are matched to the heating load of the house)
However I would caution you against installing one with the hope of saving vast amounts of money especially if you are going to hang it onto your existing system which hasn't been designed for it.
Most of the negative comments have been from those who have had a retrofit onto an existing system and then find that it costs significantly more to run than their previous gas/oil systems and they are cold as well.
Do lots of research, get three or four quotes (and not just for Mitsubishi, try Daikin, Panasonic and others) You need to get a good understanding of how they work and your lifestyle. They are very slow to heat a house as they are only running water at about 35 degrees through the system, much higher and the efficiency (COP falls away very rapidly) so ideally the unit should run almost continuously at low temperatures.
If you want to PM me I can give you more info on my system.

Cardew

A well measured post above.

Many of the complaints here are from tenants. Some owners, having forked out good money, lack objectivity in their posts - a form of denial??


You really should study both of the Energy Saving Trust trial reports. The first 12 month trial was 'disappointing' so it was extended for a further year. The ASHP manufacturers were given a free hand to improve the systems - with major modifications in many cases. On the second report, for the 29? systems tested the average 'system' COP was 2.45.

This is a very important point ignored by many:

They are very slow to heat a house as they are only running water at about 35 degrees through the system, much higher and the efficiency (COP falls away very rapidly) so ideally the unit should run almost continuously at low temperatures

Unlike gas/oil/LPG which can be switched on and quickly heat the house, you are heating most of the day. If you are out at work you are not comparing 'like with like' on energy consumption.

AsaMac

Thanks for your help so far guys. I'll go and have a read of those field trails, it's all a bit overwhelming.

My wife and me both work from home so the slow steady heat would be ideal. The thermal mass of the thick stone walls mean that the house takes an age to heat up as it is so, theoretically, it going all day would be perfect.

I'm a bit worried about the pipework though, I mean downstairs is all brand new underfloor heating but the upstairs is radiators circa 1990 so I'd better see what impact that's going to have.

Is there anyway to move a whole thread to another section?

matelodave

I suggest that you just ignore anything else on this one and just use the other forum.
I'll put any further comments on the other thread

beanyman1000

Hello All
New to Forum, can anyone tell me if there is an "UP TO DATE" list of the Best heat pumps. i.e .2015. as it seems that they are advancing quickly and last years or earlier, may be out of date.
I am interested in the Mitsubishi, but can't seem to find out anyone who knows the best one.
Not interested in prices or which is the best value, I just want to get the best one.
Manufacturers obviously claim theirs is the best. Boo Hoo. but then they wouldn't they?
Suppliers and installers recommend the ones they are supplying.
Is there any help out there? no good saying to me read the blurb, as it is all complete double Dutch.
Looking forward to any replies with interest.:beer:

Cardew

beanyman1000 wrote: »

Hello All

Not interested in prices or which is the best value, I just want to get the best one.
Manufacturers obviously claim theirs is the best. Boo Hoo. but then they wouldn't they?

Welcome to the forum.


I fear you will never get an answer to your(valid) query.


The problem is that the performance of any heat pump is extremely sensitive to the installation, type of property(i.e. insulation, underfloor heating/radiators) and the way it is operated i.e temperature required in house and temperature of domestic hot water required.


If you look at both trials carried out by the Energy Saving Trust you will see the huge variety of results obtained over the two twelve month trial periods; a COP ranging from a ghastly 1.2 to an excellent 3.0+.


To get the results you want it would need to have absolutely identical houses in the same location, with the same type of heating(ufh/radiators), and operated in the same manner. Even then that wouldn't be any use if your house/operating requirements were different.


P.S.
Where do you get the information that heat pumps have improved over the last couple of years? More new-builds have underfloor heating which is obviously better suited to heat pumps.

matelodave

When I was looking for my unit just over five years ago I tried to get similar info and it wasn't available.

I trawled around several installers and found a couple of vendors who had set up demo systems in their premises which gave me the opportunity to see how they were configured and to quiz them about performance and reliability as well as after sales back-up.

In the end it looks like most of them use the same compressor units, heat exchangers and other components and so it's down to the configuration and controls.

They all quote CoP figures which are a bit like VW emission figures - done in a lab under controlled conditions and bear no relationship to real world operation.

You need to do your own homework and find an installer who has experience with several different makes - the one I found had two Daikin (LT & HT), a Mitsubishi, a Panasonic and a Sanyo system to demonstrate coupled to both underfloor & radiator systems. I had the opportunity to see and hear them running, look at configurations and to put a lot of my own input into how my system was to be put together. I also did my own heat loss calculations (on a room by room basis) to check the various quotes.

The installer I used actually did a good job and I'm pleased with the system which is now in it's 6th winter of operation. It's doing what it says on the tin and is working out to be as economical as I'd hoped.

We don't have any previous costs to compare it with as the system was installed into a property that we renovated which previously had manky old storage heaters.

I've taken a lot of time to understand how it works and tweaked the controls to suit us and our lifestyle (mainly at home all day in a 140m2 detached bungalow brick built in 1986 with cavity wall insulation, 17 year old double glazing, 300mm+ loft insulation but with no underfloor insulation).


The heat pump produces all our hot water and heats the house using a polypipe overlay underfloor heating system. we could probably have improved it even more by ripping up all the floors and insulating underneath them but the cost & effort was greater than the perceived benefit.

We are all electric, on a standard tariff and in our worst year (2012) used 8688kwh and our best (2014) 5699 kwh. I guess our non heating/hot water consumption is around 3500kwh.

beanyman1000

Thanks for getting back, sorry so long as I have been to UK for family visit.
My house is a one off I'm afraid, I have been told that my house needs 6-8 Kw to counter the heat losses, it is very old but now well insulated.
The info I got for the IVT was just found on line by typing in IVT AIRX heat pump
there are several comments to read about it, some even saying that the new air source pump compares Ground source,

Claire71uk

Since 2011, in Norfolk East Anglia, probably mildest area for weather in uk.

Local Council insisted upgrade from storage heaters to Ecodan 8.5kw air heating system. Entire system, TVR's and piping have all been independently replaced after only 2 years... still having pressure issues and cold spots. Or system shutdowns. Every visit, new parts required, several pressure tanks, even raidiators less than two years old?

Not to mention EDF have replaced our electric meter twice, new estimated yearly bill states £24,000 for two bed disabled bungalow.

We began with electric at £35 per week, now w/Ecodan £60-100 per wk with less usage and on economy 7. Heating water only between 5-6am.

Jan 2016, entire heating unit exploded? It wasn't de-icing if homeowner would have cost 10k to replace, or no heating at all. As it was had no heating or hot water for week plus while arranging new parts, well council quibbling with Mitsubishi?

Not even Council agent, Nor Mitsubishi knew how to manage issues, so after replacement (accused of causing breakage) council set it up for them and LOCKED user pad?? Also, relocated to above 7ft high, out of reach for wheelchair user.

The pathways and drain off around unit surrounded by green slim... causing Moss and slim hazards on paths.

Given choices now, why would anyone choose a system disregarded by USA and others as NOT FIT FOR PURPOSE.

Now local council employed contract manager for fitting Air heating units, as Repairs manager whom instructed user lock out? Since, two different contracted agents attempt to service unit each year?

So, stuck with £20,000 electricity shortfall according to EDF ... where does one start... Council, Ecodan or Electric supplier?

Household income maybe 8k?