Availability of combined A2A and A2W units in the UK

[FelixtheHousecat]

Hello buildhub residents.

My first post here.

I'm self-building a passive house in East Anglia and I'm looking at heating, DWH and potentially cooling solutions.

 

My question is this - a load of companies seem to manufacture units that are either multi-split of mini VRF and have A2A refrigerant inverters available with a hydrobox for DWH (that's my reading of the marketing docs, please correct me if I've misunderstood the technology)

But NONE OF THEM are available in the UK it seems (I hope I'm wrong, but I've called them and nobody knows anything about these units here).

Does anyone have a good sense of why they're ether not bothering with the UK market, or why they're unable to get them licensed here?

Maybe something to do with the distortions created by the Boiler Upgrade Scheme?

 

The list has most of the big guys one it:

 

Mitsubishi PXZ series - see around page 25 of this pdf here: https://kokotasgroup.gr/entypa/pdf/FULL_PRODUCT_HEATING_WEB--281-29_6166.pdf

Samsung EHS TDM Plus Climatehub - https://samsung-climatesolutions.com/en-gb/b2c/our-solutions/home/heat-pump-solutions/heating-cooling/tdm-plus.html

Daikin Multi Plus - https://www.daikin.ie/en_gb/product-group/air-to-air-heat-pumps/multiplus.html

Panasonic Aquarea Ecoflex - https://www.aircon.panasonic.eu/IE_en/happening/aquarea-ecoflex/

LG Multi-V compact with Hydro kit - probably too big for my house, but anyway  https://images.b2bmkt.lge.com/Web/LGElectronics/%7Bc5c4ca24-a96c-4aed-9cc9-97e1f6dbabf2%7D_2023_4Q_White_paper_Hydro_Kit_Low.pdf?

ArgoClima iseries split - https://www.keaneenvironmental.ie/argoclima/iseries-split-pump/

Midea CirQHP- https://www.prnewswire.com/news-releases/midea-comes-to-ish-frankfurt-2023-with-its-latest-water-and-space-heating-solutions-301774592.html

 

And yet - nothing available in the UK....

 

[JohnMo]

Why make stuff complex A2W and a few fan coils - done, you don't need to flow much above 32 to 35 so a SCoP of 4.5ish. Or UFH flow 30 or below and better SCoP.

 

You can cool with UFH or fan coils - fan coils are better at cooling, UFH feels better at heating.

 

Keep it simple.

 

 

[FelixtheHousecat]

I am indeed likely to go with a 5kW ASHP, 250L UVC, plus 5x fan coils, and that's it.

 

Not doing UFH.

My partner is an insurance underwriter, and the majority of the domestic claims are for ingress of water in badly installed systems.

Not a headache I need with the small heating requirements - won't have a passive slab, will be beam and block.

 

But that wasn't really my question.

It was about why these units are being manufactured and sold in other countries, including Ireland, but not in the UK.

[SteamyTea]

1 minute ago, FelixtheHousecat said:

But that wasn't really my question.

It was about why these units are being manufactured and sold in other countries, including Ireland, but not in the UK.

16^th June 2016 made trading with the relatively small UK market a lot harder.

It is what everyone wanted, so that is what we have.

[JohnMo]

There is an ArgoClima agent in London and another in Eire. Their monobloc unit can water fan coils and heat the cylinder via refrigerant.

 

Would say because the BUS grants don't allow you use those type of units, so likely to be small scale sales, so why bother importing?

 

8 minutes ago, FelixtheHousecat said:

Not doing UFH.

My partner is an insurance underwriter, and the majority of the domestic claims are for ingress of water in badly installed systems.

Never heard that before. My UFH has the total of 14 joints all above floor level. So possibly less than a fan coil or radiator system.

[FelixtheHousecat]

6 minutes ago, SteamyTea said:

16^th June 2016 made trading with the relatively small UK market a lot harder.

It is what everyone wanted, so that is what we have.

 

How infuriating and depressing

 

[Iceverge]

19 minutes ago, FelixtheHousecat said:

My partner is an insurance underwriter, and the majority of the domestic claims are for ingress of water in badly installed systems.

 

Are you sure it's from UFH and not leaking DHW?

 

In any case, time over again I would only have pipe joints and cylinders in a room with a floor level drain to allow any leaks to drain away safely. I'm surprised that insurance companies don't insist on it for new builds. 

 

Deciding on how to heat a passive house is a real pain in the ass. The heat demand is so low that any cash you spend on the capital install makes a massive chunk of the lifetime running costs, so any expensive system is almost impossible to justify over simple restive heating. 

 

We have a passive house in Ireland. Currently heating it with a single 900w plug in electric radiator in the living room. (It needs another rad added when the weather gets frosty) It doesn't really matter where you put it so long as it's downstairs, the heat tends to even out. I've bought a split A2A unit from Daikin, yet to be installed. It should reduce our spend on electricity from €900 to €200 so there's about a 2-3 year payback for a semi DIY install.  I've also recently put some patio style heaters in the bathrooms for a bit of extra comfort when emerging from the shower. 

 

For DHW we just use an immersion. As this can run solely on cheap night rate time of use (TOU) electricity it costs €600/year for a family of 5. I'm hoping some PV install will reduce this to less than €200. 

 

Alternatively one of these might be a solution for a similar saving.

 

 

 

If I was to do it all again I think I'd go one of two routes. 

 

 

1. Install UFH pipes in a concrete slab and an UVC with a large coil. Run it all a cheap TOU electricity and pick up a cheap monoblock ASHP when the opportunity arose if the house performance justified it. 

 

2. Install a single A2A unit in a central area of the house downstairs for heating. Install under tile electric UFH in the bathrooms for comfort or patio/IR heaters. Use PV with divert or a dedicated heat pump as shown above for DHW. 

 

 

 

 

 

 

 

 

 

[Kelvin]

Our house isn’t passive but it’s still very efficient and I’ve been heating it with one 2kW oil filled rad and it’s very comfortable. Once we are living there with all the appliances on etc we’d only need the rad on colder days. My ASHP is sitting on a pallet yet to be installed (being installed tomorrow) If I was doing this again I’d have got a bit closer to passive standard, built it a bit smaller, possibly slightly less glass and possibly not installed an ASHP with UFH. That said UFH is very nice underfoot. 

[PhilT]

9 minutes ago, Iceverge said:

Deciding on how to heat a passive house is a real pain in the ass. The heat demand is so low

I notice some companies make a combined MVHR + heat pump of low capacity, presumably circulating warm air? Seems ideal in concept - what would prevent this from being a popular choice for a passivhaus?

[Kelvin]

1 hour ago, FelixtheHousecat said:

 

 

Not doing UFH.

My partner is an insurance underwriter, and the majority of the domestic claims are for ingress of water in badly installed systems.

 

 

 

Any plumbing system badly installed will leak. UFH should have no joints under the slab/floor or hidden in walls.  Typically it’s all in one place with all the joins visible and accessible albeit you might have the manifolds in different parts of the house. Had three UFH systems going back almost 20 years. All the issues I’ve had have been the typical pump failures, valve failures, expansion vessel, and PSU. 

[FelixtheHousecat]

1 minute ago, Kelvin said:

Any plumbing system badly installed will leak. UFH should have no joints under the slab/floor or hidden in walls.  Typically it’s all in one place with all the joins visible and accessible albeit you might have the manifolds in different parts of the house. Had three UFH systems going back almost 20 years. All the issues I’ve had have been the typical pump failures, valve failures, expansion vessel, and PSU. 

 

Yeah, agreed.

Which is why I wanted something like this https://www.daikin.ie/en_gb/product-group/air-to-air-heat-pumps/multiplus.html

one high level unit upstairs, one console unit downstairs, and the UVC right next to the bathroom - very little copper piping.

The most likely thing to go wrong with be the condensate pump failing on one of the units.

Probably would have been a cheap-ish installation.

 

But I can't buy it with any UK support or warranty, and I don't fancy bringing it over on the ferry from Ireland and having nobody to install it.

[JohnMo]

1 hour ago, SteamyTea said:

16^th June 2016 made trading with the relatively small UK market a lot harder.

It is what everyone wanted, so that is what we have.

Would doubt Brexit had much to do with this subject. You can get ASHP easily enough, you can A2A easily enough also.

 

Suspect as mentioned, grant scheme is the main issue, second Aircon isn't covered under permitted development, so would require planning permission, third, the population away from build hub, wanting Aircon is very limited. Forth the population wanting Aircon and water heating in a single unit is even less of a market. 

 

If set on A2A do that, and something like a Dimplex Edel for hot water. Or time of use and direct immersion, some PV would allow most your summer hot water to be free.

 

What are you doing for bathroom heating?

[FelixtheHousecat]

22 minutes ago, JohnMo said:

If set on A2A do that, and something like a Dimplex Edel for hot water. Or time of use and direct immersion, some PV would allow most your summer hot water to be free.

 

What are you doing for bathroom heating?

 

Had the same thoughts.

Arostor or similar for DWH plus A2A for heating/cooling.

Priced it up and came out quite a bit more, plus I'd prefer the HP unit outside the house - plant room is kind of close to a bedroom.

 

Then there's the planning permission. In a conservation area and had a fair bit of trouble just getting permission to build.

Won't allow Solar PV because you can see the back (south) of the house from a side-street, though I'm pushing back on this.

Which makes immersion and direct electric a bit harder to justify.

 

Having said that, the bathroom will just be an electric towel rail! So only direct electric....

Thought about dual fuel and a second heating zone, but I don't want the complexity.

[Iceverge]

1 hour ago, PhilT said:

MVHR + heat pump of low capacity, presumably circulating warm air? Seems ideal in concept - what would prevent this from being a popular choice for a passivhaus?

 

Nilan do the Compact P. Lovely unit.

 

€9k plus the Vat plus install in Ireland when I looked 5 years ago. 😬

[Iceverge]

1 hour ago, Kelvin said:

If I was doing this again I’d have got a bit closer to passive standard, built it a bit smaller, possibly slightly less glass and possibly not installed an ASHP with UFH. That said UFH is very nice underfoot

 

Ditto. Nothing really matches not needing the energy initially. 

 

Although I'm not sure a properly tuned UFH ASHP setup really feels warm to the touch. Maybe some others could comment? @ProDave @TerryE 

[JohnMo]

Mine is not warm to touch, but not cold either. Our rooms are around 20 to 21, the floor is only a couple of degrees warmer.

 

Poor insulation (U values) required to get a warm floor.

 

 

[Kelvin]

12 minutes ago, Iceverge said:

 

Ditto. Nothing really matches not needing the energy initially. 

 

Although I'm not sure a properly tuned UFH ASHP setup really feels warm to the touch. Maybe some others could comment? @ProDave @TerryE 

The floor tiles don’t feel cold though as they will be slightly warmer than the room temp. In houses I’ve lived in with tiled floors and radiators vs UFH the UFH has always felt nicer to walk on barefoot. 

[HughF]

Mine runs at 28-29 on the mixer…. Whole house sits at 22.5-23. Rads + fan coils + ufh in the new build.

[joth]

1 hour ago, JohnMo said:

Would doubt Brexit had much to do with this subject. You can get ASHP easily enough, you can A2A easily enough also.

 

Suspect as mentioned, grant scheme is the main issue, second Aircon isn't covered under permitted development, so would require planning permission, third, the population away from build hub, wanting Aircon is very limited. Forth the population wanting Aircon and water heating in a single unit is even less of a market. 

 

If set on A2A do that, and something like a Dimplex Edel for hot water. Or time of use and direct immersion, some PV would allow most your summer hot water to be free.

 

What are you doing for bathroom heating?

Yup broadly agree. Brexit certainly hasn't helped, as people can't self import these sort of things anywhere near as easy. But BUS is the biggest one. 

I think there's loads of people that want ac, and there's an existing fgas industry here installing it. They are primarily commercial and have no interest in domestic HW, and the BUS limit means they never will.

 

It's hilarious if you stop and think, how a2a is not eligible for BUS, but a2w2a (as I also did) is perfectly allowed.

 

 

[Iceverge]

38 minutes ago, Kelvin said:

In houses I’ve lived in with tiled floors and radiators vs UFH the UFH has always felt nicer to walk on barefoot. 

 

Me too but the house I lived in had gas CH + UFH and minimal insulation. 

 

36 minutes ago, HughF said:

Mine runs at 28-29 on the mixer…. Whole house sits at 22.5-23. Rads + fan coils + ufh in the new build.

 

Sounds like a complex setup? What was the need for all 3?

 

1 hour ago, FelixtheHousecat said:

Priced it up and came out quite a bit more, plus I'd prefer the HP unit outside the house - plant room is kind of close to a bedroom.

 

 

1 hour ago, FelixtheHousecat said:

Won't allow Solar PV because you can see the back (south) of the house from a side-street, though I'm pushing back on this.

Which makes immersion and direct electric a bit harder to justify.

 

1 hour ago, FelixtheHousecat said:

Having said that, the bathroom will just be an electric towel rail! So only direct electric

 

It sounds like a simple monoblock ASHP and UVC and UFH would be the most satisfactory setup in that case. 

 

The requirement for an F-Gas installer for any split unit is a disadvantage, perhaps outweighing the efficiency gains. Also the greater potential for a refrigerant leak could well undo any CO2 savings. 

 

I think you are over estimating the potential for a water leak from the UFH Vs DHW. 

 

One point to consider with a specific split unit system and various fan coils is that you may run into difficulty replacing one element if it fails in years to come. Better to have a separated system tied to no particular manufacturer in my opinion. 

[FelixtheHousecat]

30 minutes ago, Iceverge said:

I think you are over estimating the potential for a water leak from the UFH Vs DHW. 

 

Yeah, maybe I am. I concede that.

 

The thing that gets me, though, is that even at a lower probability, the impact is far greater and the monetary and disruptive cost to rectify is far higher.

Digging up floors is never fun.

It could also go unseen for a while longer than above ground.

Anyway, that's my risk tolerance - well, my partner's actually. I suppose dealing with insurance claims all day will do that to you.

[FelixtheHousecat]

35 minutes ago, Iceverge said:

It sounds like a simple monoblock ASHP and UVC and UFH would be the most satisfactory setup in that case. 

 

I want cooling, too.

I have only a 1% overheating risk above 25 degrees and I may be able to further design that out, but 25 degrees isn't my comfort zone for sleeping, so I want cooling - even if only a little.

 

I know a few on here are successfully doing cooling above the dew point with UFH, but I want it to work out of the box with no additional programming or stress and without so much predictive planning going on to monitor the weather later in the day.

[joth]

A2w with a FCU does give very effective and responsive cooling in demand. However it's not exactly "out of the box". Virtually no UK installer knows how to do cooling or FCU installation, let alone both. The parts are hard to source and you need to add additional controls for the FCU. 

[HughF]

49 minutes ago, Iceverge said:

 

Me too but the house I lived in had gas CH + UFH and minimal insulation. 

 

 

Sounds like a complex setup? What was the need for all 3?

 

 

 

 

It sounds like a simple monoblock ASHP and UVC and UFH would be the most satisfactory setup in that case. 

 

The requirement for an F-Gas installer for any split unit is a disadvantage, perhaps outweighing the efficiency gains. Also the greater potential for a refrigerant leak could well undo any CO2 savings. 

 

I think you are over estimating the potential for a water leak from the UFH Vs DHW. 

 

One point to consider with a specific split unit system and various fan coils is that you may run into difficulty replacing one element if it fails in years to come. Better to have a separated system tied to no particular manufacturer in my opinion. 

Ufh in the extension, as it made zero sense to pour a concrete slab and not put pipes in…. Rads in most of the house because, rads… and fan coils where we didn’t want the rads sticking out of the wall (access)….

 

pretty simple really, whole lot runs on weather compensation with a fixed temperature to the ufh through a mixer. No thermostat, no zone valves, no buffer tank…

[Iceverge]

30 minutes ago, FelixtheHousecat said:

 

I want cooling, too.

I have only a 1% overheating risk above 25 degrees and I may be able to further design that out, but 25 degrees isn't my comfort zone for sleeping, so I want cooling - even if only a little.

 

I know a few on here are successfully doing cooling above the dew point with UFH, but I want it to work out of the box with no additional programming or stress and without so much predictive planning going on to monitor the weather later in the day.

 

Ok. 

 

Install 1 X A2A unit in a central area. We bought the Daikin FTXM25R. About £900 plus install. It should have good cold weather performance, cooling heating and WiFi out of the box. 

 

(Allow ducts + power supplies for other units if you think you'll need them, you probably won't, PHPP will guide you)

 

Install a stand alone Heat pump for the DHW.  Joule do some. @Thedreamer has one. Or my preference would be a stand alone one like I posted above. Say another £900 plus "as large as you can fit" SS cylinder. 

 

Then put some towel rads in the bathrooms. 

 

<£3k spent. COP of 4-5 on heating. COP of 2.5-3 on DHW. Zero chance of leaks associated with space heating. 

 

Surely the point of a passive house is you can do away with all the complex heating systems. Keep it simple and don't combine space heating and DHW unless there an obvious benefit to doing so.