I bought a Heat Pump

Mstty

Do new builds qualify for rhi?

Yes, providing it is a self-build property. RHI is not available if you are a property developer or have bought a new-build property from a developer.

Sadly the original owners did not build this themselves they bought it off the house builder so the MSC and RHI does not apply.

Ah well can't miss what we don't have with regards to an MSC. 

I might look at some cheapish energy monitor for the Heatpump.

Mstty

What I can tell though is that the house is very good at keeping heat in. Very dull day here today 12oC outside temperature and no heating. Not one room is below 18oC and if we get some sunshine it will soon pop up to 20oC/21oC.

So even without the MSC the heat loss, I suspect, will be on the lower end of the scale when I start looking at the compensation curve. Will start low and go from there probably end of September or if the weather is mild mid October.

Reed_Richards

I'm not an expert but I think you only need to know three parameters, the desired internal temperature, the maximum water temperature you can (or want to) run your heating at and the outside temperature where your house will be just warm enough with the heating running at maximum output.  Normalised to those three parameters, I conjecture that every weather compensation curve will be the same (unless underfloor heating and radiators are different in the way their heat output varies with water temperature).

michaels

Has anyone purchased an ASHP heat pump recently, what are the costs just for the Heat Pump bit (excluding any rad upgrades etc).  Thanks

Reed_Richards

The model that I have would appear to cost just over £5k now:
https://www.orionairsales.co.uk/lg-therma-v-air-heat-pump-monobloc-57degc-hm121mu32-12kw40000btu-240v415v50hz-10432-p.asp
I don't know anything about this particular vendor.

michaels

Reed_Richards said:

The model that I have would appear to cost just over £5k now:
https://www.orionairsales.co.uk/lg-therma-v-air-heat-pump-monobloc-57degc-hm121mu32-12kw40000btu-240v415v50hz-10432-p.asp
I don't know anything about this particular vendor.

Should be VAT free now?  How much should installation be - obviously no doubt prices are much higher if it qualifies for the grant?!

matelodave

In my experience, once the government stick their oar in with grants, requiring significant qualifications  (like the MCS scheme) or lots of paperwork to claim the grant or dispensation, then the price of stuff goes up, either to compensate for the aggro or to add to the profit margin

As far as I can see, the zero Vat is on installations which include the components, so you cant go and buy a heatpump and install it yourself and get the VAT refunded, nor can you buy the heatpump at highly advantageous discounts and get an MSC installer to fit it for you. I may be wrong but as ever nothings as simple as it should be.

Have a wade through this Energy-saving materials and heating equipment (VAT Notice 708/6) - GOV.UK (www.gov.uk)

Having a bit of trawl through the interweb seems to have a similar opinion - zero VAT is on stuff that is being installed by an accredited installer not stuff that you can buy over the counter or from a supplier.

Martyn1981

Martyn1981 said:

Many thanks RR and Shiny. So if heating needs are low enough, my existing wet system might squeak through with a high temp HP in the coldest scenario, but it's always going to be a compromise then. Silly thought I had was that the smaller pipes might not effect efficiency, it would just take longer to heat the house ....... which of course means running everything for longer ..... which of course means less efficiency, doh!

I suspected that they would always be less efficient at a lower temp than a normal HP, but useful to get that answered.

Maybe it's silly to chase the last of the gas as it's reasonably low already, and just keep investing in RE schemes etc..

More pondering me thinks.

Blast from the past!

Been pondering this issue again, and looking into heatpumps again, possibly with the intention of replacing all the microbore in the house .... then I had a thought?

To get a heatpump sized appropriately, are the assessors allowed to take into account other existing heating, or is the system supposed to be sized to work in isolation?

Here's my thought - The one room in the house where heating is most likely to be inadequate during the worst couple of winter weeks we get, every 3 or 4 years, is also the one with a 3.5kW A2A unit. So even with sustained temps just under zero, it should manage a COP of 2(ish) and around 1.5/2kW of heating, which will be more than enough for topping up, without the need for a high temp heatpump.

As well as shoulder month use on PV, we have actually been using this unit overnight on E7 in the winter to help reduce GCH use. We put the temp to 18C, and leave the door half open.

Does that make sense? And I can't believe I didn't think of it back in April when chatting.

70sbudgie

Martyn1981 said:

To get a heatpump sized appropriately, are the assessors allowed to take into account other existing heating, or is the system supposed to be sized to work in isolation?

Here's my thought - The one room in the house where heating is most likely to be inadequate during the worst couple of winter weeks we get, every 3 or 4 years, is also the one with a 3.5kW A2A unit. So even with sustained temps just under zero, it should manage a COP of 2(ish) and around 1.5/2kW of heating, which will be more than enough for topping up, without the need for a high temp heatpump.

As well as shoulder month use on PV, we have actually been using this unit overnight on E7 in the winter to help reduce GCH use. We put the temp to 18C, and leave the door half open.

Does that make sense? And I can't believe I didn't think of it back in April when chatting.

It makes sense that the assessors take into account alternative heat sources. It doesn't make sense that a HP would be expected to work in isolation. For example, presumably they take into account an immersion heater on a HW tank, which avoids the need for higher temperatures from the HP to heat the HW. 

I would like to think that what they would do is assess the room where the A2A unit is and then include that unit's output. Especially if you already use it with the door open to provide heat outside of the room it is located in.

I have to add the caveat that I have applied logic rather than have any experience and it has become apparent to me that logic is not always appropriate. I am still trying to persuade my sister to share her HP survey, so that I can see for myself what the assessment report looks like.

My boiler is too new to replace with a HP just now, but I am trying to identify improvements I can make that would smooth the transistion to a HP in the future. 

Screwdriva

Martyn1981 said:

To get a heatpump sized appropriately, are the assessors allowed to take into account other existing heating, or is the system supposed to be sized to work in isolation?

Technically speaking, assessors are meant to design the system to run on only air source heating. No immersion element use either. This was explained to me by our installer before we decided to switch to a Viessmann 200-W boiler.

70sbudgie said:

My boiler is too new to replace with a HP just now, but I am trying to identify improvements I can make that would smooth the transistion to a HP in the future. 

Very interested in your findings. So far, we discovered the need to:

1) Increase radiator piping diameter. Very disruptive but can be mitigated with...
2) Maximize possible insulation (floor, 400mm loft, wall, triple glazing etc).
3) Upsize radiators from single to the largest possible double fin, double panel T22 type.
4) UFH heating dramatically increases heat pump SCOP.


Only then was a SCOP of 4 achievable in our early 90s home.