Air-air heat pump/air con for single room.

[AF62]

The above is a typical example of mainstream heat-pump related features

It’s a Telegraph article.

The Telegraph know their readers froth with uncontrollable excitement at any articles that are damming of heat pumps (and a range of other technology topics including BEVs, smart meters, the demise of cash, etc.) and so they just publish articles that feed their reader’s prejudices. What they do publish has the most tenuous link to reality, so is pointless to consider as evidence when attempting to identify whether something is good or bad.

That’s not to say the heat pump industry sites or energy saving group sites are any better, as they feed into their reader’s prejudices in a similar, but opposite, way.

i.e. it’s damn hard to get a proper independent view.

[Howard]

Hi Howard,

You'll know I've followed your air-to-air heat-pump journey with huge interest, and it's great to hear that you've seen such good results from your installation, but I've kept meaning to come back to you after reading a number of recent 'heat pump' related articles, where they almost universally seem to be panning the suitability of 'whole house' air-to-water heat-pump systems, and where the clear benefits that you've seen from your own type of multi-room air-to-air heat-pump installation is rarely, if ever, mentioned in them.

However, critics of heat pumps say the devices remain far too expensive for most households and that installing them will require costly adaptations in many homes.

The above is a typical example of mainstream heat-pump related features that seem to solely concentrate on the well-known downsides of 'whole house' air-to-water heat-pump installations, and I'm yet to encounter a single related article that properly highlights the clear benefits of the type of multi-room air-to-air heat-pump installation that you're clearly over the moon with.

As an owner of this type of technology, and as someone who's experienced the clear benefits of it over this past winter, are you equally surprised to see this 'heat pump' technology get lumped together and criticised like this, when they should clearly be getting discussed as completely separate installation-types, with the benefits and downsides much more clearly defined between them?

Is it any wonder that the type of relatively cheap heat-pump installation that you've installed and are happy with are not more widely known about and considered, when it seems clear that there would be huge benefits in doing so?

This seems such a crazy situation to me that I'm struggling to see how the industry are actually allowing it to happen...

Cheers,

Itsallaguess

Itsallaguess

You are right that heat pumps don’t seem to get a good press. But I’m really pleased to read that AF 62, DrFfybes and funduffer also have good experiences of air to air systems.

In answer to your comments (which I have paraphrased above), neighbours and friends were generally very suspicious of the benefits of aircons. The disadvantages they worry about are that they are bulky, noisy and expensive to run. A couple of friends, when challenged, have taken some time to find my operating external unit because it is very quiet and I have “hidden” it in a frame which serves as a table next to our bbq.

We’ve used the downstairs unit almost every day this winter and cut our usage of gas by over 20% without using much extra electricity.

Going slightly off-topic I’m pretty sure that the hundreds of pounds of gas we’ve saved is because I’ve finally found how to run my powerful condensing boiler much more efficiently. It’s a system boiler which is probably over-specced for our five bed house with only two of us in it most of the time. This winter, instead of letting it run continuously, I set it to heat the water in our large, well insulated thermal store in the early morning for an hour when we get up and in the evening for an hour. At the same time I run the central heating. So instead of modulating frequently it has to work really hard in cold weather twice a day. This seems to be a much more efficient way to use the boiler. The heat pump is used to heat one room that we use most of the time and the CH is just used occasionally for background heating.

If one wanted to completely replace the gas boiler, then heating the water with an immersion heater would be ok but ducting warm air to all downstairs rooms might be the problem. Aircon ducting in the loft is easy to install out of sight but the cavity between downstairs ceilings and upstairs floors isn’t big enough to conceal ducting for the downstairs rooms, so wall units are the only solution I have seen.

Hope that answers some of the questions.

regards

Howard

[UncleEbenezer]

The Energy Saving Trust (EST) estimates that a typical household will end up paying between £7,000 and £13,000 for an air source heat pump, before any voucher discount is applied.[/i]

My river-source heat pump was going to cost significantly more than that. But through a bizarre government incentive scheme I'd recoup most of the premium over a new gas boiler over seven years.

Not sure if that scheme still exists, but if it does I hope it's been rationalised. One thing that seemed particularly perverse is that it wouldn't have been available for a communal scheme serving all five houses in my building (or better still also our neighbours in other buildings on the same site) that could have been much more efficient than separate installations. So the substantial savings and economy of scale we might have had through pooling resources were actively disincentivised.

[csearle]

Haven't read the whole thread (even enough to check if I've already replied). I can report that a cheap air-sourced heat pump is perfectly adequate to heat a one, two, or even 2.5 room space and can be installed by anyone with an ounce of nous providing said installer gets one that that does not require special qualifications. I have seen it done and experienced the result. I'd not hesitate. C.

[AF62]

providing said installer gets one that that does not require special qualifications

Good luck finding anyone who will sell you one of those these days.

Back in the past anyone could buy 'self-install' systems that were pre-charged with the CFC coolant, but although such systems are still available for sale, the law is far more rigorously enforced and suppliers will now only supply you if you give the details of the registered F-Gas installer who is going to fit it for you.

The only systems that are available for anyone to buy have butane as a coolant - far less efficient and being butane...

[DrFfybes]

Haven't read the whole thread (even enough to check if I've already replied). I can report that a cheap air-sourced heat pump is perfectly adequate to heat a one, two, or even 2.5 room space and can be installed by anyone with an ounce of nous providing said installer gets one that that does not require special qualifications. I have seen it done and experienced the result. I'd not hesitate. C.

To be fair you are fairly savy than most and being in a trade more aware of how to do things properly and the pitfalls of a bodge. A poor install is also unlikely to kill the occupants, merely damage the environment.

As AF62 says, only certified people can install FGAS ones, although I gather certain online suppliers don't actually check with the person who's number you supply that they are actually going to install it. Of course when you come to sell the house you might have to declare it.

Interestingly both my quotes said they only install Daikin/MHI and neither would touch a cheap system purchased online - they said they don't even go out to repair them any more unless they have to. Both said they'd learnt their lesson and long term it cost them money to have to keep going back. On the paperwork I got from the chap I used I couldn't have sourced (!) it any cheaper myself.

Paul

[csearle]

No idea what coolant was used in the system I saw installed. (I just supplied the fused-connection unit and wired it up.) It was about 8ish years ago. I switched it on to test if it was working and in a small amount of time the 2.5 room space was pleasantly warm. So whatever coolant and efficiency it had, it was effective!

I remember my plumber friend explaining that it came as a kit that didn't need any special qualifications because all the liquids/gases were already sealed in it. I think he said that after joining the indoor unit pipes to the outdoor unit he had to turn one valve to evacuate the pipes (don't know how that worked) then another valve to release the coolant into the vacuum. C.

[scotview]

aware of how to do things properly and the pitfalls of a bodge.

Paul

I've looked at a few youtubes re Air to Air installs. One room, "blower" type installs look fairly straight forward and are good for hot/cold aircon type applications.

The main limitation that I see is the requirement for significant air ductwork for multi room applications. There also seems to come a point when at least two external units are needed if the rooms are far apart.

[AF62]

I remember my plumber friend explaining that it came as a kit that didn't need any special qualifications because all the liquids/gases were already sealed in it. I think he said that after joining the indoor unit pipes to the outdoor unit he had to turn one valve to evacuate the pipes (don't know how that worked) then another valve to release the coolant into the vacuum. C.

Those are the ones you can still buy, but only if you can provide the details of the F-Gas engineer who is going to do that for you.

However, getting it installed may not be that much more expensive as installed aircon is now zero rated for VAT but buying the kit to install yourself is subject to 20% VAT.

It is zero rated, not because it is aircon, but because it is an ASHP and an heat homes in a 'green' way.

[funduffer]

aware of how to do things properly and the pitfalls of a bodge.

Paul

I've looked at a few youtubes re Air to Air installs. One room, "blower" type installs look fairly straight forward and are good for hot/cold aircon type applications.

The main limitation that I see is the requirement for significant air ductwork for multi room applications. There also seems to come a point when at least two external units are needed if the rooms are far apart.

Yes, the duct work is the problem with multi-room aircon installations driven by one big heat pump.

We have a bungalow and have, like Howard, a wall mounted aircon unit in one room, and a gas boiler central heating system. We also have seen significant reductions in gas usage this winter by heating one room with the aircon unit, avoiding running the gas central heating much during the day, We have solar as well which makes daytime running of the heat pump even cheaper still.

For a bungalow, it would be possible to have a large heat pump and a wall mounted aircon unit in each room, but it would not be that cheap - probably £10k to £15k, I would guess. Duct work in a bungalow would be relatively straightforward, as it could all be in the loft. Multi-storey houses would involve wall or floor duct work. Then there is the hot water system to add to it all.

This is why heat pump to hot water (radiator) systems are being promoted, as they piggyback on existing gas boiler systems. These are not cheap either.

I have not yet concluded what I would do if the gas boiler died. Would I replace it? Would I install an aircon unit in each room? Would I stick with water filled radiators and a large heat pump? I think the answer will be the relative price of gas and electricity at the time. At the moment, electricity is roughly 3x that of gas per kWh, and a heat pump has a SPOC of about 3, so broadly even stevens in running costs. If electricity was 2x gas, that would be a game changer for me, and push me towards a heat pump solution.

FD

[DrFfybes]

For a bungalow, it would be possible to have a large heat pump and a wall mounted aircon unit in each room, but it would not be that cheap - probably £10k to £15k, I would guess. Duct work in a bungalow would be relatively straightforward, as it could all be in the loft. Multi-storey houses would involve wall or floor duct work. Then there is the hot water system to add to it all.

This is why heat pump to hot water (radiator) systems are being promoted, as they piggyback on existing gas boiler systems. These are not cheap either.

FD

One issue is the in-room units need a drain if they are in cooling mode, so tend to be on an outside wall or near a bathroom. Ours is rear entry pipework, although I expect there are kits to bring the feed in from all angles.

We were quote £18k for a pump to replace the boiler, with voiced doubts it would be able to heat the house without more rads, which there isn't space for. Underfloor would require digging up 5 concrete floors, quote of £5k+ per room, so around £50k, and at the end of the day they are no cheaper than gas per kW output.

We are detached so can have several '2 room' air to air systems scattered around - one at each end for lounge or office and the bedroom above, and one at the back for the Kitchen and diner, and bathroom above. That would have come to about £7k, but with our low sloping ceilings went for office only on the first.

We're getting solar/battery later in the year, the aim being that most of the time the battery will run the air heating in the evenings in winter (neighbours have a 8kW panel/10 kWh battery system that charges the battery fully most days in winter). Winter mornings we still have the gas boiler or could top the battery up overnight on a cheap tariff.

Total up front cost expected to be about £15k, which at current energy prices is about a 4 year payback.

Paul

[scotview]

We're getting solar/battery later in the year, the aim being that most of the time the battery will run the air heating in the evenings in winter (neighbours have a 8kW panel/10 kWh battery system that charges the battery fully most days in winter).

Paul

Some good posts so far.


Most of the current (pardon the pun) solar/battery installs are around 10kW solar/12kWh battery, this takes care of "normal" daily electricity use. I think an issue will arise when whole of home electrical heating/hot water/power, of whatever variety, will need a realistic, say 60 kWh/per day supply in the winter months. If night time tariffs, feeding large battery units cannot be utilised, the homeowners will be on premium daily electricity rates. It is doubtful that DNO's will welcome such large battery installs. The government's energy strategy is maybe a bit short sighted in this respect regards 2030 deadlines.

[DrFfybes]

Most of the current (pardon the pun) solar/battery installs are around 10kW solar/12kWh battery, this takes care of "normal" daily electricity use. I think an issue will arise when whole of home electrical heating/hot water/power, of whatever variety, will need a realistic, say 60 kWh/per day supply in the winter months. If night time tariffs, feeding large battery units cannot be utilised, the homeowners will be on premium daily electricity rates. It is doubtful that DNO's will welcome such large battery installs. The government's energy strategy is maybe a bit short sighted in this respect regards 2030 deadlines.

Good point - we use about 4000 kWh of gas a month in winter, however if the heat pump hype is to be believed this translates to 1000-1500kWh of leccy, which at 40+ per day plus our usual 13kWh/day use is close to your estimate. Our use is also concentrated to evening and morning, so a battery charged overnight at cheap rate and topped up in the day by solar should help. Savings also come from only heating the rooms we want with warm air, rather than the boiler which runs flat out for 10 min to heat the pipework before the return temp rises and it modulates down.

I actually think the DNOs will be OK with batteries - after all it increases off peak demand and 'flattens the curve' which should make their life easier. Battery prices per kWh are falling, panel technology improving, and adding another battery if energy prices stay as they are should be a simple operation.

Paul

[csearle]

"...and a heat pump has a SPOC of about 3'''

WTF does that mean?

[funduffer]

"...and a heat pump has a SPOC of about 3'''

WTF does that mean?

It means, that on average, over the year, the heat pump will produce 3kW of heat for every 1kW of electrical power used.

I am sorry, it should have been SCOP not SPOC (typo)! Too much Star Trek!

SCOP = Seasonal Coefficient of Performance


FD

[PhilipEstrada]

A single-room air-air heat pump or air con sounds like a smart move, especially for controlling the climate in specific areas. It's great for maintaining comfort and air quality, which is crucial, especially in urban areas like NYC

[DrFfybes]

As our newest AI (no relation to Eric) has resurrected this, I thought I'd provide a quick update.

We're having some serious building works, this is our old spare bedrrom with the kichen below,

and have stored most of our stuff and relocated into the 2-up 2-down 1950s extension, which includes the "snug" with the air to air 'split' unit.

Some days we run the heating if MrsF is WFH, other days we just use the split. The gas bill is about half, no surprise as we're heating half a house, but also we are actually warm for the first time since we moved in. A combination of the insulated plasterboard from when we refurbed the "snug" (apparently the original cottage cold store and workshop) and an adequate heat source means we can maintain 19C easily. The unit is quiet, costs about a pound per day to run in this balmy weather, twice that when it was freezing outside, compared to about a fiver per day extra to keep the heating on above the usual 2 hours morning and 1 at bedtime. We usually leave it ticking over on Eco if we are in and out of the garden, and turn it off when we go out properly.

An added benefit is simply setting it to "Fireplace mode" overnight, which is marketing speak for "fan only" which is very good for airing the washing when we've gone to bed. There is also a dehumidify setting which we don't use.

Paul

[BullDog]

A single-room air-air heat pump or air con sounds like a smart move, especially for controlling the climate in specific areas. It's great for maintaining comfort and air quality, which is crucial, especially in urban areas like NYC

Mr Estrada, are you a human?

[scotview]

we use about 4000 kWh of gas a month in winter, however if the heat pump hype is to be believed this translates to 1000-1500kWh of leccy, which at 40+ per day plus our usual 13kWh/day use is close to your estimate.

Paul

That's a significant bit of transformation to your property.

I suppose the 60000$ question is, would you heat your entire rebuilt house solely by heat pump, or would you still prefer a gas boiler and/or wood burner in the mix somewhere ?

[DrFfybes]

That's a significant bit of transformation to your property.

I suppose the 60000$ question is, would you heat your entire rebuilt house solely by heat pump, or would you still prefer a gas boiler and/or wood burner in the mix somewhere ?

Short answer - "no" - not AHSP supplying rads or underfloor. We'd still need to install extra rads and we replaced the gas boiler 18 months ago anyway. The house is only 18 feet so one room deep, which means a lot of extrnal walls and windows, and ASHP don't save anything costwise over gas at the moment (people I know who've converted say they spend slightly more). Also we swap between rooms throughout the day, and the lower ASHP temps seem to mean running it for longer, whereas at the moment we can heat a room up pretty quickly. The new higher temp ASHPs coming along look interesting though.

The wood burner was removed to be replaced by the Split unit. Cleaner, quicker, easier, and doesn't take up one of the few walls in the house that doesn't have a window.

The new lounge incorporates the old dining room but with the stairs partitioned off, will have a multisplit unit, and the main bedroom which is above it will also have a unit, mainly for summer cooling.

The original place was only 12 feet front to back, with a 6 foot extension downstairs, which meant the middle upstairs bedrooms were pretty small once a corridor had been taken off the front. The original roofline is visible as the old gable end in the pevious photo (which has the remaining bedroom and only bathroom in it). Also being 230 years old, insulation wasn't a priority. The timbers weren't in great condition in many places.

The new roof will extend over the downstairs extension, but more importantly be thicker and higher and have insulation, which might bring the place up to a standard that could cope with ASHP heating. The old roof was so low we couldn't have insulated inside either.

The old lounge and diner are being merged into one and we will put insulated boards on the wall, however the concrete floors will remain uninsulated. You can see we are bricking up some of the 3(Yup!) sets of patio doors the new room would have had which will help with heat retention,



'major transformation' probably describes it, but no surprise the cost is not cheap. And that's the problem with a lot of UK housing stock - I know ours is a little to the extreme end of things but insulating a lot of the older properties you see in the villages and towns takes a lot of space or costs the same as several decades of energy bills.

Paul