A2A quote for aircon

BuildTheWall

Asked a local company for a quote on installing aircon for two bedrooms as the newbuild house gets too hot and the windows dont face the direction of wind in the summer. 
To avoid installing ugly outdoor units for regular air con, as the windows open on to the road in front, the surveyor suggested installing an air 2 air source heat pump with the outdoor unit facing the garden and routing the pipes through lofts to the bedrooms. The quote is £3.5k including a worcester bosch Multi Split CL50000i 5.3kw outdoor unit and 2x2.6kw indoor units for Bedroom 1 and Front Bedroom. 
1) does the quote sound reasonable?
2) the quote says it can be used for heating in the winter. how would that work with a A2W heat pump i also plan to install? if we dont use the other rooms (mostly in ground floor), can I turn off the A2W heat pump and use this instead?

QrizB

I have no knowledge of Worcester Bosch A2A heat pumps.

BuildTheWall said:

The quote is £3.5k including a worcester bosch Multi Split CL50000i 5.3kw outdoor unit and 2x2.6kw indoor units for Bedroom 1 and Front Bedroom. 
1) does the quote sound reasonable?

Yes, that sounds reasonable to me. @danrv paid double that for a larger system with 3x indoor units back in 2021. Thread here, install photos on page 6.

BuildTheWall said:

2) the quote says it can be used for heating in the winter. how would that work with a A2W heat pump i also plan to install? if we dont use the other rooms (mostly in ground floor), can I turn off the A2W heat pump and use this instead?

@danrv installed his primarily for heat, to replace his storage heaters. @Martyn1981 has A2A units that supplement his main heating system. You might find you don't need the A2W for most of the year, and can fit a much smaller one when taking the A2A units into account. You might even not need the A2W at all.

Rodders53

Get alternative quotes and options from others including other brands of aircon... Daikin, Mitsubishi Electric, Mitsubishi Heavy Industries et al... Different installers have different brand loyalties and discounts.  W-B is a new one on me.

You will need Planning Permissions for the A-A in addition to an A-W heat pump... even if the latter unit is permitted development.

You are unlikely to use heat in a bedroom in autumn / winter. Heat from downstairs will naturally get upstairs and most don't want bedrooms too warm.  Even if you fit no radiators in those rooms the A-A will be used very little I'd have thought.  We've been known to run our bedroom unit on cool in the winter if we forget to close the door to get the temperature down for sleeping.

Investigate the relative cost of in-ceiling aircon vents as opposed to wall mount split units in the bedrooms if that is feasible.

wrf12345

A single A2A unit is anywhere between £750 to £1500 supplied and installed, depending on where you live in the UK (London being the most expensive area) and the quality/size of the unit. You are allowed two under permitted development so may be better to go that route.

Martyn1981

QrizB said:

I have no knowledge of Worcester Bosch A2A heat pumps.

@danrv installed his primarily for heat, to replace his storage heaters. @Martyn1981 has A2A units that supplement his main heating system. You might find you don't need the A2W for most of the year, and can fit a much smaller one when taking the A2A units into account. You might even not need the A2W at all.

Totally agree. And just to be clear 'supplement' is an under statement, as the combi boiler got ripped out two weeks ago, to make room for a HW cylinder (heated via immersion on cheap night rate leccy). So it better be enough. 

TBF, got through last winter fine, with pretty cold period in January. That's two 3.5kW A2A units downstairs, leaking heat through the house. I've also added a leccy towel rail (with integrated hot air fan boost) in bathroom, and two oil rads where used last winter in two bedrooms (400W & 800W fo a few hours), but still experimenting, and their use went down, when I simply upped the temp on the A2A units by 1C.

Highest leccy/gas bill was January at £110, hoping that will drop by £10 next year, as leccy oven goes in this week, then gas can be disconnected, and SC will be gone. £110 was general leccy use, plus space heating, plus gas for DHW and oven, and 'fuel' for two BEV's.

[Edit - Sorry, meant to say, bill is cheap as we have battery storage, so we can charge them up on cheap rate, and run the A2A units from batts during the day. Also, we run the A2A units harder at night (23.30 to 05.30) to 'pre-heat' the house, again on cheap rate leccy.]

1930's 3 bed semi.


Sadly, regarding air con, whilst heat rises fine, the downstairs units can't really cool upstairs. I also suspect, that A2A units upstairs would produce too much heat, with not enough (possibly very little) travelling downstairs. I'm not great with heat, so for two nights this last summer, I did sleep downstairs,

Martyn1981

BuildTheWall said:

To avoid installing ugly outdoor units for regular air con, as the windows open on to the road in front,  

Just to say, that whilst I appreciate what you mean, it's not the end of the world, and one of our units is on the front of the house ...... but we can't see it IYKWIM.

Also, if you Google something like "covers for air to air heat pumps", you will find loads of options to make them look a bit better. But of course be careful not to restrict air flow too much.

silverwhistle

Martyn1981 said:

TBF, got through last winter fine, with pretty cold period in January. That's two 3.5kW A2A units downstairs, leaking heat through the house. 

Is that two internal units on a split with one external unit, or two separate systems?

Thanks.

What you've done is similar to what I'm considering as including the standing charge I'm paying over 10.5p per kWh for gas. With a mid-terrace and a wood burner with plenty of seasoned wood for those cold January spells I certainly wouldn't need anything bigger than your 7kWhs.

Martyn1981

silverwhistle said:

Martyn1981 said:

TBF, got through last winter fine, with pretty cold period in January. That's two 3.5kW A2A units downstairs, leaking heat through the house. 

Is that two internal units on a split with one external unit, or two separate systems?

Thanks.

What you've done is similar to what I'm considering as including the standing charge I'm paying over 10.5p per kWh for gas. With a mid-terrace and a wood burner with plenty of seasoned wood for those cold January spells I certainly wouldn't need anything bigger than your 7kWhs.

Hi SW. Two separate units. The first was intsalled in ~2017 following discussions on the Green & Ethical board about trying to use excess PV generation to displace some, or all GCH in the shoulder months. Worked fine, contributing some or all heat depending on the months from Mch to June, and then Sept/Oct. Obviously sometimes those months need a lot .... or no heating.

Slightly different story now perhaps, as export rates are available, so the economics need more thought, but with a COP of 3 to 4 perhaps in the shoulder months, with air temps of 10C+, I suspect heating is still beneficial v's export.

We were so pleased with the results, that we bit the bullet and got a second unit in 2020. Also we stuck that one on the front of the house, taking advantage of new neighbours moving in and doing major renovations. I assumed they wouldn't want to rock the boat with planning issues. No contact from council yet(!)

I get the impression that installing two seperate units is still the same cost, or cheaper than a single multi-split, but you'll need to check and research. Also a single unit can plug straight into a domestic socket, ideally only one per ring main, so our back unit is on the kitchen ring, and our front unit on the downstairs ring. A multi-unit (and I think 5kW+ singles (not sure)) will probably need to be hard wired to the CU on their own supply.

The big shift for us, was adding even more PV last year, and a battery. At that point we could heat the house all winter on cheap rate leccy, via battery storage. Worked better than expected, so GCH not needed 2024/25 winter at all, so being stripped out. Hopefully my guesses and estimates are correct, we had a pretty cold week last January, and whilst one week is not definitive proof, the units didn't work flat out, and the house heat didn't appear to drop off at all. That suggested to me, that we have a bit of slack in the system, hence GCH removal.

The A2A units seem to pull about 300-500W each most of the day when it's cold, with ~1kW when de-icing.

We only imported day rate leccy (batts empty) on 2 or 3 occassions in January. All were very cold days, one was a washing day, and the others were near zero PV generation. Only meant we pulled ~500W for a few hours in the evening. That was with 20kWh of batts, but I just added 8KWh more ..... more for fun, than financially sensible.

Sorry for all the waffle, just trying to think of issues/concerns that you (or others) may be pondering and would like to know.


Oh, just a thought, but may be worth waiting and watching for developments on the home heating support grant. A2A have already got some support, such as zero VAT on purchase and install, but the review should be complete soon, and maybe there's a small chance that A2A will start to get its share of the love v's the £7.5k support for wet ASHP installs.

danrv

Martyn1981 said:

Oh, just a thought, but may be worth waiting and watching for developments on the home heating support grant. A2A have already got some support, such as zero VAT on purchase and install, but the review should be complete soon, and maybe there's a small chance that A2A will start to get its share of the love v's the £7.5k support for wet ASHP installs.

The support is for greener heating so I guess that's why the ASHP wet systems get funding priority.
Otherwise more people might be encouraged to fit cooling AC.

Martyn1981

danrv said:

Martyn1981 said:

Oh, just a thought, but may be worth waiting and watching for developments on the home heating support grant. A2A have already got some support, such as zero VAT on purchase and install, but the review should be complete soon, and maybe there's a small chance that A2A will start to get its share of the love v's the £7.5k support for wet ASHP installs.

The support is for greener heating so I guess that's why the ASHP wet systems get funding priority.
Otherwise more people might be encouraged to fit cooling AC.

Personally, I think the ability to also cool the property during a heatwave is a plus v's a wet ASHP system.

And on those hottest days, we'll be generating 40-50kWh of leccy and helping to 'green' one third of the houses on our road.

And even if a property with A2A doesn't have PV, UK supply side PV generation will be peaking.

barker77

Martyn1981 said:silverwhistle said:

Martyn1981 said:

TBF, got through last winter fine, with pretty cold period in January. That's two 3.5kW A2A units downstairs, leaking heat through the house. 

Is that two internal units on a split with one external unit, or two separate systems?

Thanks.

What you've done is similar to what I'm considering as including the standing charge I'm paying over 10.5p per kWh for gas. With a mid-terrace and a wood burner with plenty of seasoned wood for those cold January spells I certainly wouldn't need anything bigger than your 7kWhs.

Hi SW. Two separate units. The first was intsalled in ~2017 following discussions on the Green & Ethical board about trying to use excess PV generation to displace some, or all GCH in the shoulder months. Worked fine, contributing some or all heat depending on the months from Mch to June, and then Sept/Oct. Obviously sometimes those months need a lot .... or no heating.

Slightly different story now perhaps, as export rates are available, so the economics need more thought, but with a COP of 3 to 4 perhaps in the shoulder months, with air temps of 10C+, I suspect heating is still beneficial v's export.

We were so pleased with the results, that we bit the bullet and got a second unit in 2020. Also we stuck that one on the front of the house, taking advantage of new neighbours moving in and doing major renovations. I assumed they wouldn't want to rock the boat with planning issues. No contact from council yet(!)

I get the impression that installing two seperate units is still the same cost, or cheaper than a single multi-split, but you'll need to check and research. Also a single unit can plug straight into a domestic socket, ideally only one per ring main, so our back unit is on the kitchen ring, and our front unit on the downstairs ring. A multi-unit (and I think 5kW+ singles (not sure)) will probably need to be hard wired to the CU on their own supply.

The big shift for us, was adding even more PV last year, and a battery. At that point we could heat the house all winter on cheap rate leccy, via battery storage. Worked better than expected, so GCH not needed 2024/25 winter at all, so being stripped out. Hopefully my guesses and estimates are correct, we had a pretty cold week last January, and whilst one week is not definitive proof, the units didn't work flat out, and the house heat didn't appear to drop off at all. That suggested to me, that we have a bit of slack in the system, hence GCH removal.

The A2A units seem to pull about 300-500W each most of the day when it's cold, with ~1kW when de-icing.

We only imported day rate leccy (batts empty) on 2 or 3 occassions in January. All were very cold days, one was a washing day, and the others were near zero PV generation. Only meant we pulled ~500W for a few hours in the evening. That was with 20kWh of batts, but I just added 8KWh more ..... more for fun, than financially sensible.

Sorry for all the waffle, just trying to think of issues/concerns that you (or others) may be pondering and would like to know.


Oh, just a thought, but may be worth waiting and watching for developments on the home heating support grant. A2A have already got some support, such as zero VAT on purchase and install, but the review should be complete soon, and maybe there's a small chance that A2A will start to get its share of the love v's the £7.5k support for wet ASHP installs.

What units did you get - the 3-500w draw is really good