Cost of installing all in one heat pump water heaters and VAT

[JtG]

I had settled on the Dimplex Edel 170l (but  might wait for the Mixergy iHP) as it has quietest operation, and it will be in the attic above my carer's bedroom.   There's only the 2 of us, and only one of us uses hot water so 170l should be more than adequate.   I  have had trouble getting prospective installers to understand what they are and to quote. 

 

 I've had a quote of £1000 that was withdrawn, and 2 quotes of £2500 - that's installation and materials and vat on those. but not the cylinder or ducting.

 

Could anyone advise me if that is reasonable please?  How many half days of work should that cover, please?   

 

Its to put marine ply, in the attic area, where we are placing the cylinder, bringing up a electric cable up from the boiler cupboard below, and removing the boiler from the kitchen, and capping the gas, and installing the new system.  It is going directly above the boiler cupboard so I hope that reduces the amount of change to my piping.

 

Also could anyone comment on the VAT, please?   I have reviewed the energy saving materials and 2.20 includes heat pumps and does say spare OR WATER HEATING.   So I think 0% is right...

 

 

"2.20 Air source heat pumps

Air source heat pumps use the air as a source of heat. They absorb heat from the outside or surrounding air and transfer that into useable heat in the home for space or water heating, or both."

 

https://www.gov.uk/guidance/vat-on-energy-saving-materials-and-heating-equipment-notice-7086

 

I post in the HMRC customer forum, who linked back to the link above, so none the wiser!

 

 

[RichardL]

Can you get separate quotes for each job from electric, plumber etc as a control/comparison point?

I'd be interested in your cylinder location choice - in my build its a tradeoff between best location for cold/hot water feeds and best location to get a warm air feed from the conservatory.

[JohnMo]

Section 2.20 says they are in included a heat pump heating water, it is a fixed unit. So should qualify. But has to be purchased and installed as a single transaction. So if the plumber isn't providing the cylinder you need to pay Vat on their bill.

 

 

[JtG]

Thanks JohnMo.   That's how I read it and I will make sure my installer buys it.

 

RichardL - you are right that the position is a dilemma; between the hot water travelling further and the optimising the COP with a warmer environment.

 

All the heat in my house comes from electric heaters so I wasn't keen on that being sucked up to heat the water.   So it is a case of ducting from the kitchen (where the combi boiler is) and 1m from the kitchen sink and 2m from the shower, but you do need a drain which we can't do from that point..  My Alternative (its a bungalow) is directly above that ktichen cuboard, in the attic, so all the copper pipes are in perfect position for installing and without ducting which can be £700..  I'm aware my COP will suffer in the winter - I'm even thinking of making sure there's a socket to put an infrared heater up there for that cold week like we had last Dec.

 

Do you know what the minmum temperatures are in a conservatory in the winter?  Better than an attic?

 

Jt

[JamesPa]

11 minutes ago, JtG said:

  I'm aware my COP will suffer in the winter - I'm even thinking of making sure there's a socket to put an infrared heater up there for that cold week like we had last Dec.

Surely that's wrong.  The cop of the dhw will suffer yes, but if you are suckìng heat from your house that you need (as you do in winter) it's the combined cop that matters. 

 

Effectively you now have a two stage heat pump between OAT and water temperature.  Is that more efficient than a single stage heat pump?  Maybe but I doubt it.  And if your first stage has a cop of <1 because you have used an ir heater,  not all of the energy from which will end up in the HP, I would think definitely not.

 

On the first (drawing heat from the house) I'd check the figures and work out the combined cop.  On the second (using a separate pre-heater) I wouldn't bother.

 

Obviously in summer, when you might be thankful for cooling the house, its a different matter.

Edited May 6, 2023 by JamesPa

[RichardL]

35 minutes ago, JtG said:

minmum temperatures are in a conservatory in the winter?  Better than an attic?

Probably not much in it - the odd sunny day in the winter is more likely to warm my conservatory whereas the attic probably depends if you have insulation under the tiles, if the insulation is sitting on top of the ceiling the roof I would guess stays cold?
(emphasise guessing - every house will be different)
 

[RichardL]

28 minutes ago, JamesPa said:

not all of the energy from which will end up in the HP, I would think definitely not.

I'd be inclined to turn on the immersion before trying to pre-heat the hot water air pump intake?
Its expensive - but 100% will go into the water.

[JtG]

Yeah - my idea with the FIR panels was precautionary to stop the system icing up at the very coldest points of winter, when they system is pulling in air and  the attic temperature was seriously cold, so 4 hours for few days of the winter....