ASHP: Ecodan vs LG vs Vaillant

[BartW]

Hi,

I am looking into the choices between different ASHP units available, and have found that half decent units start from £3k + VAT onwards. 

 

In summary, VAillant aroTherm 5kW would start shade over £3k, but would need a tank bought separately. LG do a mono block that is around the same, but tad more and also needs a tank.

 

Mitsu Ecodan do a monoblock with a tank here https://www.orionairsales.co.uk/mitsubishi-electric-ecodan-quhz-w40va--ehpt20q-vm2ea-air-source-heat-pump-with-thermal-store-4kw-a-10965-p.asp and that @ just under £4k seems good value.

 

Now from the technical point of view, is the thermal store an equivalent to a megaflo tank? If so, would one of the stronger units from LG or Vaillant be a better option for sizing, and flexibility to add a bigger tank? One can get a 250L tank from Main or similar for around £500 - £600. 

 

Is that the right thought process? And if so, assuming that installation is not much more involving than that of a Gas boiler, why is an average quoted cost of ASHP for a typical detached dwelling oscillating between £8k and £12k? (or more?).

 

Sorry for all the rather blunt questions, but it is my first attempt at ASHP having learned from an earlier post (thank you so much!) that the RHI has been extended until 2022.

 

Regards 

Bart

 

[PeterW]

23 minutes ago, BartW said:

why is an average quoted cost of ASHP for a typical detached dwelling oscillating between £8k and £12k? (or more?).

RHI premium. Or installers making a fast buck on MCS installs to be clearer. 
 

A non-MCS install of the same kit is £6k all in 

[BartW]

3 minutes ago, PeterW said:

RHI premium. Or installers making a fast buck on MCS installs to be clearer. 
 

A non-MCS install of the same kit is £6k all in 

 

I know a Gas Safe engineer that might be able to help, so would I need to ensure he is MCS registered for the RHI to be utilised?

 

A bit of a daytime pisstake...

 

Make something twice as expensive for the 50% of the premium to be written off over 7 years. I mean, what is the point of the government trying to sway people to become carbon neutral?

 

 

 

[PeterW]

TBH on a new house that is well insulated your RHI payments are never going to cover the premium so it’s easier to go the non-MCS route. 

[BartW]

1 minute ago, PeterW said:

TBH on a new house that is well insulated your RHI payments are never going to cover the premium so it’s easier to go the non-MCS route. 

Which would borderline warrant me installing it myself, and getting the Gas Safe engineer to commission and certify the whole thing?

 

I am weighing up the savings of the ASHP vs Gas boiler + £2k connection to the grid. I am not far off!

 

[Mr Punter]

I have weighed up the gas route. If you can get a connection for £2k you will save a fair bit over the lifetime of the boiler.  Get a setup so you can switch to ASHP cheaply in the future.

[Gav_P]

Many of us on here have installed our own... it ain’t rocket science! Plenty of experienced people here who can help you all the way through it, but mainly in get the system right in the first place. The biggest problem with ASHPs is that they are ‘incorrectly sized’ or used in the wrong property. 

[BartW]

27 minutes ago, Mr Punter said:

I have weighed up the gas route. If you can get a connection for £2k you will save a fair bit over the lifetime of the boiler.  Get a setup so you can switch to ASHP cheaply in the future.

£2k connection is something I could avoid by not having gas. Another £2k would come from not having a tank and boiler, and another £600 for commissioning. Now take the cost of a said ashp and tank and I am virtually back to zero difference which would be keen. 
 

the property is 2/3 storey (gym on top floor) with 180sq m GIA. 3/4 bedroom with UFH on all floors, and below 0.15uValue for the entire envelope. About 80sq m of glazing double or triple. 
 

7kW unit too much, but 4kW not enough probably. So aiming between 5 and 7kW but care about 250L water tank for 4 showers in the morn (for when the kids come), with everyone getting equal share of hot water. 
 

those are my credentials. 

[SuperJohnG]

If you go ASHP you need a bigger tank as the water is stored at a lower temp, circa 48 degrees for most people here, hence it is mixed down less when compared with storing water at 65 degrees from a gas boiler. 

 

The ecodan units are used wide here and I have heard good things. Don't know much about the other. 

 

I'm going with 8.5kW  ecodan and 400l tank in my house with 190 sqm GIA. Three bathrooms. But I have two young children and I also like to spend 30 mins standing in the shower.  So 250 may do you but id be tempted to go 300.  Gledhill are named regularly  here along with another I cannot for the life of me remember just now. 

 

Id be tempted to do some calcs on your heat loss to check a 5kW will cover it. What levels of airtightness are you aiming for? And where in the country are you? 

[BartW]

The build is in Graven Hill, OX25 so South East. The max air exchange rate is 3Pa/h. Not looked at that fully yet. Started off with open panel TF from likes of MBC or Fleming, went Durisol, but now giving the TF “a second look”. 
 

all slightly confusing. Or perhaps adding up, otherwise I would just have everything ?

[ProDave]

As others are saying, they are easy to self install or install be normal tradesmen. Just be sure they are capable of reading the manual as particularly with the electrics there are some differences from say a system boiler, and some plumbing differences like you never ever use a 3 port mid position valve with an ASHP. 

 

And many of us cynical old folk on here believe the MCS scheme is a rip off designed to suck most if the RHI payment out of the customers hand into the installers coffers.

 

a 250L tank will NOT be big enough for 4 showers.  We have a 300L tank and it has been know to run out if all 3 of us shower in sequence.  Duration of a shower seems proportional to the square of the length of your hair!!! (I don't take long to shower)  Remember with a low power ASHP the DHW re heat time is a lot longer than with a gas boiler.

[joth]

1 hour ago, ProDave said:

And many of us cynical old folk on here believe the MCS scheme is a rip off designed to suck most if the RHI payment out of the customers hand into the installers coffers.

 

 

I've said this many times, but you don't have to be a cynic to think this. It is literally what my friend who worked at BEIS confirmed the goal was -- albeit she used rather different words, something like "To establish and grow the trained professional installer network.". NOT to make cost of ownership lower in the short term. (In the long term it should because of increased supply and market economics -- but that's probably a decade off).

 

It's actually really clever economics: they're using Joe Public to front loans to the industry to fund training, which are paid back by the government over 7 year period.  Installers get immediate cash-flow boast to cover their short term surge in training costs; Joe Public get the warm fuzzies for "Being Green" *and* for believe they're getting cash handout from The Man for doing so; government get to spread the cost over >1 political term.

 

[ProDave]

I would call that simple Fraud.  Tell the public you will get a grant to help with the cost, but don't tell the public you will be forced to use a scheme of installers who have deliberately inflated the costs so they end up with the grant money and you are no better off than if you just bought the damned thing and paid someone normal rates to install it.

[joth]

Welcome to politics.

[joe90]

I am a “cynical old bugger” who installed his own ASHP etc with a bit of help from others here. Yes RHI is fraud in my opinion. Any bad press about ASHP is where they are not installed/programmed correctly.

[MikeSharp01]

1 hour ago, ProDave said:

And many of us cynical old folk on here believe the MCS scheme is a rip off designed to suck most if the RHI payment out of the customers hand into the installers coffers.

Sadly this is now a standard political pattern wheeze and is used all over the economy. The help to buy scheme for new homes is another example and we will no doubt see many more flogging along with the green agenda. Don't get me started - back to the build ......

[J1mbo]

5 hours ago, ProDave said:

a 250L tank will NOT be big enough for 4 showers.  We have a 300L tank and it has been know to run out if all 3 of us shower in sequence.  Duration of a shower seems proportional to the square of the length of your hair!!! (I don't take long to shower)  Remember with a low power ASHP the DHW re heat time is a lot longer than with a gas boiler.

 

I have a 250L tank and this is providing adequate to supply 5 showers in two hours with the (12kW) ASHP set to heat the cylinder for 30mins max with 20mins break for space heating.

 

RHI does require MCS which adds cost. The system I have consists of ASHP, buffer, plater heat exchanger, and Telford HP cylinder plus associated controls. RHI is covering 85% of the cost and it took about 15 man-days to install and commission. There are hidden costs like the new circuit, the MCS paperwork itself, heat loss surveys required etc. The scheme has worked out well for me provided it lasts for the 7 years promissed.

[joth]

5 hours ago, ProDave said:

 

a 250L tank will NOT be big enough for 4 showers.  We have a 300L tank and it has been know to run out if all 3 of us shower in sequence. 

I seem to recall you keep the tank at a fairly low temp, around 40ºC?

 

The Vaillant can go to over 60ºC  which is an alternative option to increasing the tank size. (Obviously it will cost a more to heat because the ashp will run a little less efficiency)

 

[newhome]

2 hours ago, J1mbo said:

I have a 250L tank and this is providing adequate to supply 5 showers in two hours with the (12kW) ASHP

Can I be cheeky and ask what you paid for your install please (assume it was zero rated?). I’m getting quotes for a similar size set up. 

 

 

[jfb]

17 hours ago, BartW said:

Mitsu Ecodan do a monoblock with a tank here https://www.orionairsales.co.uk/mitsubishi-electric-ecodan-quhz-w40va--ehpt20q-vm2ea-air-source-heat-pump-with-thermal-store-4kw-a-10965-p.asp and that @ just under £4k seems good value.

 

That looks interesting for what I need as well.

 

Anyone know if these can be put into reverse for cooling?  I know with some other Ecodans people have said it can be done (though not obvious from the literature or sales speak).

[Mr Punter]

16 hours ago, BartW said:

£2k connection is something I could avoid by not having gas. Another £2k would come from not having a tank and boiler, and another £600 for commissioning. Now take the cost of a said ashp and tank and I am virtually back to zero difference which would be keen. 
 

the property is 2/3 storey (gym on top floor) with 180sq m GIA. 3/4 bedroom with UFH on all floors, and below 0.15uValue for the entire envelope. About 80sq m of glazing double or triple. 
 

7kW unit too much, but 4kW not enough probably. So aiming between 5 and 7kW but care about 250L water tank for 4 showers in the morn (for when the kids come), with everyone getting equal share of hot water. 
 

those are my credentials. 

 

You could just buy a big boy gas combi.  Unlimited showers.  No messing with tanks etc.  Loads cheaper to run.  Any gas plumber can install cheaply.  You could get one with a bit of storage.

 

A fair bit of the electric you use on your ASHP is made by burning gas.

[jfb]

18 hours ago, BartW said:

Mitsu Ecodan do a monoblock with a tank here https://www.orionairsales.co.uk/mitsubishi-electric-ecodan-quhz-w40va--ehpt20q-vm2ea-air-source-heat-pump-with-thermal-store-4kw-a-10965-p.asp and that @ just under £4k seems good value.

 

Just realized that this differs from the usual Ecodans in that it uses a thermal store not an unvented tank -  presumably that means you need to get the temperature of the water higher (so less efficient).

[BartW]

5 hours ago, Mr Punter said:

 

You could just buy a big boy gas combi.  Unlimited showers.  No messing with tanks etc.  Loads cheaper to run.  Any gas plumber can install cheaply.  You could get one with a bit of storage.

 

A fair bit of the electric you use on your ASHP is made by burning gas.

I think the running cost would be comparable.

 

As for the big combi with the house size, and potential number of occupants in the future, I would probably feel better if it has got a sizeable tank for when the demand is there.

 

And the whole thing between gas vs ashp probably boils down to preference, and what one believes in. The latter being cleaner energy has got some appeal to me.

 

[J1mbo]

Well, gas will always be gas. With ASHP, the environmental impact can be controlled after installation by virtue of the grid energy mix.

[SteamyTea]

Has anyone running a heat pump, close to the maximum to get a higher water temperature, actually checked to see if the built in immersion heater is kicking in?