ASAP / aircon?

[Mart]

The challenge is that heat output from an A2A is functionally impossible to measure. I put a power monitor on my A2A and in January this year it consumed 402.35kWh. Which seems minuscule for a 5-bed house!

Similar with me. Not measured specifically, but from energy consumption, I can guestimate that mine pull 400-500W each when working reasonably hard. Can be ~1,000W when starting up, or de-icing, and maybe just 30W or so, when temps are stable. But if running all night to heat the house, then 400-500W seems about right.

They are both 3.5kW units, so I assume that's based on 700W @ COP 5.

Seems low to me, especially in cold winter, but if between them they consume 1kW, with a COP of just 2, then that's around 50kWh(t) per day, and the daytime COP would typically be a tad higher. So I think it's right(ish). Very impressive.

[Waiting on Mch bill to update my own thread, as we leave the first leccy heated winter behind with no real problems, at all, much to my surprise.]

[Mart]

I’m thinking about it. At the moment these don’t qualify for the uptp £7500 grant, BUT, the installs are VAT free.

Cheers - Rob

Sorry to be a pain, but just asking again about this, as I hadn't heard. Are they now VAT free?

[Lincs Robert]

Yes. I had a quote from a “proper” company & it was VAT free, that was for a full supply & install. It covered one outside unit and two inside split units & was bang on £4k. It was a year ago & I don’t think anything has changed in the meantime. I’m not sure how the VAT aspect is covered with supply only, but there again, 20% on £1500 gives £1800 which is still way short of the £4k quoted.

I’ve asked a renewables engineer who I know & am awaiting a call from one of his associates who is fgas registered to discuss the possibility of him commissioning units that I’ve purchased, placed in situ & drilled the appropriate holes through the walls. It’s worth asking the question I think.

Hope this helps ….. Rob

[nowty]

The official info on VAT free A2A heat pumps as energy-saving materials but like solar and batteries you cannot buy with zero VAT and do DIY.

https://www.gov.uk/guidance/vat-on-ener ... otice-7086

2.15 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.

Fixed air source heat pumps can be reversed so that they can draw heat from inside a building, thus providing cooling during the summer as well as indoor heating for colder periods of the year.

Only air source heat pumps that are permanently fixed and are not portable or moveable qualifies as energy-saving materials.

HMRC’s understanding is that most air conditioning units are air source heat pumps. However, in cases of doubt, deciding if any particular product is to be treated as an air source heat pump will depend on the facts of each case.

[nowty]

Presently propane comes under F gas as an A3 refrigerant gas - there appears to be some changes on the continent that recognise R290's differences and this could change the requirements later this year, the UK are not obligated to follow those changes but will probably do so for convenience. I guess it depends where the AI got its information from - technically its correct but regulatory wise its less clear presently.

Until then its a bit of a grey spot which I assume is why the guidelines and regulatory positions are under review.

I read an article by Mr Hendra recently where he explained why A2A HP are that bit more efficient than A2W HP - if I can find it I will post it but basically the A"A should give you a CoP around 6 to 8 where the A2W gives you typically 4 to 6 (I think thats where JB is ranging ?)

It made sense as your'e only using the one heat exchanger but I liked the explanation as it was eloquent in its simplicity.

Moxi

Makes sense to me.

With an A2W HP you might want to transfer 30℃ air to a room. Toi do that you'd need 35℃ at the rad, which would need 45℃ flow from the HP, and 55℃ at the condenser.

Whereas with A2A you blow air across the condenser directly into the room so the condenser can be at 35℃.

The challenge is that heat output from an A2A is functionally impossible to measure. I put a power monitor on my A2A and in January this year it consumed 402.35kWh. Which seems minuscule for a 5-bed house!

In a Monoblock A2W your heating the water outside and then pumping it inside, so your going to lose a little heat no matter how much insulation you have. In a Split system, the hot heat exchanger is inside the house so no losses.

I have just found the first type of Split A2W heatpumps, never seen one before, maybe its the way its going in the future in search for ever increasing COPs.
https://haierhvac.eu/products/a2w/r290-hydro-split-a2w

[Stinsy]

Yeah Vallant also make split A2W HPs. The inside unit looks a lot like a gas boiler…

[Moxi]

I have been doing some more digging and BESA is apparently up in arms that some companies are selling R290 filled conditioning units as DIY because they don’t come under the F Gas regs, BESA are the larger certifiers of Fgas via Refcom so it’s in their interest to be alarmed as it is destroying their monopoly. They admit it’s not illegal and hint that they are lobbying hard for the current review of the F gas regulations to tighten up and cover flammable like R290 so it’s ok to DIY now but may legislated against within the year.

As mentioned elsewhere- jobs for the boys.

Moxi

[resybaby]

Being 'pre packed' with the gas as such, as long as you ensure you do a decent vacuum test on the pipework with a proper pump and leave on test for a while, ots pretty idiot proof really. All thats neccesary for the gas to be sent into the refridge lines is an allen key.

One of those jobs made to sound hitec and impossible for the average guy, simply to protect a rip off racket.

[robl]

In a Split system, the hot heat exchanger is inside the house so no losses.

I think in a typical split system, in the outside unit there is an air-refrigerant heat exchanger, a compressor, and a reversing valve. So in heating mode the refrigerant pipe carries hot gas to the indoor heat exchanger where it phase changes to a liquid. It seems to me this gas will be hot and lossy outside, so should be insulated.

[Moxi]

+1 to that Resybaby.

Moxi