Air conditioning at home (planning permission!)

For many years I used a small stand-alone air-conditioning unit in my study (the box room in the house) and I even had a hole in the wall for the air vent. It just about worked in a tiny room, and needed replacing every few years. In the height of summer I would even put such a unit in the bedroom but that meant a vent out of the window which sort of defeated the object.

However, when my wife finally agreed to my converting the garage in to a "man cave" I decided to do things properly and get a proper split air-conditioning unit installed in the garage (as it was still) and four bedrooms. Yes, overkill I know, but they work well, and they serve to provide energy efficient heating in the winter. I know running air-conditioning has a cost, but it is well worth it for a good nights sleep, and being on a green electricity tariff it is not like I am contributing to climate change either.

Two units are round the side of the house where you cannot see them, but three of them are on the wall facing the road and more noticeable. I did not really think about where they were being put - just left it to the air-con installer to sort them out. In hindsight we could have done something neater and lower down, but he was concerned about children in the garden poking fingers where they should not.

Anyway, this was nearly four years ago now, and they have worked pretty well. Only one unit has developed a fault in that time, which is now fixed.

There can be only one!

Interestingly, a few years ago, someone commented on a picture or video I posted that as I had more than one unit I would need planning permission! Now, planning permission is not something I have had to worry about before, and I assumed only related to actual building work, not simply an electrical appliance. Indeed, the air-conditioning installer had not heard of any need for planning permission and he has installed thousands of these.

When do you need planning permission?

It seems any development needs planning permission, and a development is almost anything that changes the exterior appearance of the property. There are then a long list of permitted developments that allow things without planning permission, and these then have conditions and rules.

So, yes, an air-conditioning unit needs planning permission, but it can come under one of the permitted developments under Part 14 G of the The Town and Country Planning (General Permitted Development) (England) Order 2015. This lists some rules, like a maximum of one unit, not if you have a wind turbine, outside unit less than 0.6m³, not within 1m of boundary, not on a pitched roof, not within 1m of edge of flat roof - pretty simple stuff to be honest. The big one is that there can be only one (but there is a catch, read on).

If you look at air-conditioning installer web sites you will see a lot of companies reference this order and explain that you can have one unit installed without planning permission - yay!

There is a catch!

There is, however, a catch, and it is one even the council seem to be unaware of most of the time, and that is G3(a) states "the air source heat pump is used solely for heating purposes". That's right, an air-conditioning unit that cools, or heats and cools, is not allowed under this permitted development, so even if you have only one, it needs planning permission! Air-conditioning installer web sites do not mention that gem.

Does anyone care?

Well, to be honest, I assumed it would not matter. I mean who really cares?

Well, it turns out someone did! After three and a half years someone, anonymously, complained to the council that we had no planning permission. I mean what the? THREE AND A HALF YEARS!

And no, they won't tell me who complained. Oddly they did think one unit was allowed. I queried this on the basis that maybe they were confused about what I had - after all the permitted development is all about micro generation and renewable energy and wind turbines even, so maybe what I have has nothing to do with part 14 G? They confirmed that air-conditioning units did come unit air source heat pump micro generation! They also confirmed that if it did not then it would not come under any other permitted development so would need planning permission anyway! They then agreed that even one was not permitted if it cools as well as heats!

Interestingly, if it had been over four years after installation it would not matter. Apparently (thanks Neil for finding the reference, here) there is a time limit on these things. That makes the three and a half year delay mentioning it even more odd and annoying.

What next?

Well, I get a formal notice that I am in breach of planning regulations, and a questionnaire. Oddly they said I would have six months to remove them and asked daft questions like how long it will take and why, to which my answer was basically "every last minute of the six months you allow me, Why? Because I like my air-conditioning!". What kind of daft question was that anyway?

The only real option I have, if I want to keep them (duh!), is to apply for retrospective planning permission!

Applying for planning permission...

This is where the real bureaucracy starts! The council web site leads to an on-line application form, which is clear as mud. I eventually managed to make a filing, and paid the few hundred pounds for the application. I had to upload some "plans", a site plan notably, and some pictures. So, I uploaded a google earth view of the house with some arrows added and some pictures. Simple...

After a while they come back and say they need a proper site plan on a recognised scale. Hmm, but hang on, the formal notice I got saying I did not have planning permission had one of those. So I could literally send back to the council the plan that the council had sent me. They clearly have a plan of the "site" on record anyway, but I had to go through this fiasco.

Then they said they needed the size of the outside units. So I measured carefully and sent a detailed email.

Then they said that was not good enough, they needed the photographs annotated with the sizes. Really? OK, I added some arrows to the photographs with the same numbers that I had put in the email!

At this point they felt I had actually provided enough for the application to be submitted or some such, and then I am told the planner is not happy and they want a proper elevation drawing of the sides of the house on a recognised scale showing the position of the units...

OK, losing my patience and the will to live, I engaged an architect for another few hundred pounds to come and measure and do a proper drawing. He did a nice job, and they really could not argue with a proper architect's drawing could they. That worked!

Council planning web site.

At this point the planning application is published on their web site and neighbours are written to. Seems simple enough.

So I kept an eye on the site. It was not made clear to me how this works - do they have a set of rules for such things to which I have to comply, or do I just get permission if nobody objects? It seems a bit like the latter, almost.

Now I know!

Well, there was an objection filed, and guess what - objections to planning permission are not anonymous, so I know exactly who is complaining. The issue is not the units high up on the wall facing the road but the ones on the side of the house only visible from that neighbour (and only one can been seen as trees/bushes in the way of the other one).

Now, these are neighbours who are not usually a problem. We don't know them that well, beyond popping round for drinks at Christmas, etc. But they are the first to come round if they have any complaint, no matter how small. So I am shocked that this one point has taken them so long to raise as an issue! To be honest, we cannot be 100% sure they are the anonymous complainer and not just that they decided to complain once they got the letter from the council.

Their main complaint - the noise! These are really quiet units. No way the noise could be an issue surely, and at the far end of their garden behind some trees/bushes even.

Investigating the objection

So, the council investigate the objection...

One of the first steps was that the person investigating decided to visit the neighbour to hear how loud it was, and told me I did not need to be there. This seems odd, as surely they need me to ensure the air-conditioning is running when they visit. Indeed, a lot of the time the air-conditioning is "at temperature" and not running. If I am not there, then it may be totally off.

Then she said that she needed to check with environmental health to check what noise level is acceptable. But it seems she had taken no measurements or anything.

She then came back to say that I needed to have a noise consultant make a report! And yes, a noise report for all of the units, not just those facing that neighbour. Yet more cost, so I asked what levels were acceptable (in case I need to order a replacement unit that is quieter).

To my surprise she came back and said no noise report was needed, but I had to confirm the units met: "Noise resulting from the use of the plant, machinery or equipment hereby approved shall not exceed a level of 5 dB(A) below the existing background noise level (or 10 dB(A) below if there is a particular tonal quality) when measured according to British Standard BS4142: 2014 at the boundary of any adjoining or nearby noise sensitive premises."

Now call me a cynic here, but the only way I can confirm that is by getting a report from a noise consultant.

I had an alternative idea - I got the spec sheet for the air-conditioning unit and measured the distance to the boundary and sent that asking if it met the above requirement.

Time running out

Then, out of the blue, I am told time is running out - they apparently have a deadline by which to make a determination, and it was coming up! So I had a choice. They would either give me planning permission which was conditional on it meeting that noise spec. Or I could grant an extension to allow them to play ping pong with environmental health.

I double checked, and there is no chance of penalties or fines or anything. So basically I have said give me the permission, and they did. I now have planning permission!

This now leaves the ball in their (or neighbour's) court - they can complain it is too loud and they can get their noise report to prove it. If it is, and they prove it, then all I have to do is turn it off until I change to a quieter unit or re-positioning of the unit so quieter at the boundary.

In practice, as I say, these units are really quiet, so I seriously doubt they fail to meet the noise requirement.

Pondering the stupidity of this law

Having read a bit more, I wonder is there a way I could have done this better? To be clear I have not tried these and do not know the legality of them.

The simplest seems to be to get a shed lean-to on the house. This seems to be something that does not need planning permission from what I can see. Then, in the shed, install outside units for the air conditioning. This is something that does not change the external appearance of the proper and so is not a development and so does not need planning permission - no more than any other work inside the house like installing a new fridge. And also, nobody knows you have air-conditioning units so won't complain!

Another idea was to install one heating only unit as per permitted development. The air-con installer said these units can be set heat only. Then, as a separate thing on a later date you "modify" your existing installation to be heating and cooling. This modification is not something that changes the external appearance of the property and so not a development and so does not need planning permission. If I was only installing one unit I'd rely on the confusion of the council thinking there can be one unit allowed, but have this as a fall back, stating what dates the heating only install was done, and what date the modification was done. I'd probably even make a video of my making the modification. I cannot see how that falls foul of the rules at all, but does rather make a mockery of the rules.

Finally, and most iffy of ideas, was if you want more than one unit. Install one heating only (permitted development). Then install a second along side that is cooling only. Now, this does not break the permitted development on the first unit as there is only one heating unit still, but the cooling one needs planning permission - except there is a general permitted development for modifications to the properly using same materials. I tried that one as a reason to not need planning permission for cooling only and was told "I doubt your house is made of the same materials as the air-conditioning unit". However, because you do have one unit (permitted, heating only), the second (cooling only) unit is using the same materials so should come under that general permitted development. Add a 3rd and 4th as needed on the same basis. Then, one day, change all to heating and cooling as a separate step which does not change external appearance and so is not a development. Would that fly I wonder? If so, the rules really are stupid.

Anyway, what I can say from practical experience, simply budget for planning permission and go ahead without. If you are lucky they will assume one unit is allowed, or nobody will complain for four years. If you are unlucky you have to apply for permission, which seems simple enough! Well, that's my view anyway, even if not my usual "doing it right" viewpoint, sorry.


What a waste of time and money - actually not that much of my time to be honest - and now we have permission. Why did they bother?

We did think the neighbour may be trying to sell, and concerned over the air-con. My house is not the one over which they should be concerned to be honest. But if that was their plan, now they have a neighbour's planning permission "on file" and that will show in a search, so making it far more obvious to any potential buyer. Ooops.


  1. You could install a Multi split external unit... then you would only have one on the wall. I think they can do up to 6 internal units... pipe runs may be problematic though.

    1. Having one on the wall would not help as still must be "heating only" to avoid planning permission.

  2. Hmm, I recently got a really cheap portable aircon to help keep the bedroom cool. It's veryt noisy so it's good for cooling the room before bedtime but can't be left on. And it's only barely powerful enough to cool a medium sized bedroom.

    But even the small relief the last few days has been very welcome.

    Based on that I was starting to think that maybe a proper aircon would be money well spent, but this post has completely put me off doing that (plus it didn't really occur to me until now that the only real place to put the outlet would be on the front of the house and even I'd be complaining about it being there!)

  3. Why am I not surprised at the absurdity of everything to do with a Local Council?

  4. Lol, you'll almost certainly have found the culprit if they have objected.

    When I did the PP for my garage, I had the chap two doors down complain and say I shouldn't block the alley with scaffolding - of course what he doesn't know is that part of the alley is my property.

    1. I wonder why it is necessary for the objector's details to be made public on planning applications? Surely it matters not who is objecting, but rather their grounds for objection. I can't help but feel that this is not consistent with GDPR requirements. Why should people be forced to publicly declare who they are (as opposed to declaring to the planning office for administrative purposes) if their grounds for objection is independent of their identity?

    2. I think you need to know who objected for when you present evidence to counter their objection. For example if someone objects on noise grounds but the guy is 4 doors down you can say that they are too far away to be impacted.
      Why that info is totally public and not just made available to the applicant, I don't know

  5. My air con outside unit is stood on slabs on the ground. This was partly to keep it out of the sun in an almost permanently shaded corner below a fence, so it runs more efficiently. But it is also so that it is a lot less obvious, unless you go into my garden you can't even see it, and the shrubs in the garden shield the noise. Even when it is running full blast it is difficult to hear it at all outside my garden. The annual air con maintenance guy loves it to, he doesn't need ladders to get at it.

  6. It was me that commented on one of your pics ages ago about only one being allowed, I came across this after getting it installed myself, spurred on by seeing your blogs on the subject.

    There is another relatively simple solution though, get a "multisplit" system installed where one outdoor unit powers multiple indoor units.

    I guess the "heating only" aspect is aimed at allowing Air to Water heat pumps, which also attract RHI payments.

    1. Multi-split did not work (see other comment below) but anyway would not help with the "heating only" requirement.

  7. Actually, surely you could argue they are always used for heating purposes - it's just that you are heating outside with heat from your house!

    1. I think they would then apply the same logic that is used for TV licensing. If you can call it logic. Derangement might be a better way of putting it.

  8. It might also have helped that you can get "multi-split" systems, where multiple internal units share a single exterior heat rejection unit - then, you could probably have heated/cooled all the rooms with one. Install it in September or October, as a heating only unit, then six months later "decide" to do the "modification" to enable cooling as well?

    Yes, all very stupid and pointless, and crazy that the noise regs are so subjective and unclear.

    1. We did that initially - but they cannot cope with one room heating and one cooling, which happened way more often than you would expect. Shame, as they could just move heat from one room to another and be even more efficient!

    2. Daikin VRV systems can do exactly that, move the heat from one room to the other, with one single external unit.

      The "heating only" thing, as mentioned above, seems a little silly, you're always heating something and cooling something else. You can cool outdoors while heating indoors, or cool indoors while heating outdoors. The net effect is always heating - there are losses in the process - so arguably it's always "heating".

  9. By the way, whoever did the brickwork blocking that door up behind tbe air con units did an awful job. The bricks aren't laid straight and there is mortar slathered all over the place. Definitely not a proper brickie.

    1. That was done like 20 years ago, and yes, not good.

  10. Honestly, those units deserve some sort of award for ugliness anyway, regardless of whatever noise they make. It appears everyone who makes AC units expects them to be installed on rooftops, out of sight.

    (A shame you can't stick a housing around them really, perhaps open at the top, just to hide the 60s industrial metal horror show a bit. But no doubt that would require *more* planning permission.)

    I have memories of a sequel to N. K. Jemisin's _The Hundred Thousand Kingdoms_ in which it was noted that in that novel, painting your house any colour other than white was heresy and would probably result in summary execution. Now *that's* a planning law with teeth.

    1. It would make a lot of sense if they designed units to go in a loft with a vent to outside or something... It would also make a lot of sense if they did a simple wooden slatted enclosure so they could neatly be positioned at ground level and not look too bad. Shame really.

    2. A ground source heat pump might look neater than air source, but you'd have to dig a lot of a garden up to lay pipes in a trench. And I have no idea what you can get as basic air con units with a ground source.

  11. Interesting is the neighbour the one with two satellite dishes?
    Some councils only allow one dish without planning permission but add anymore and you need it.....

  12. We came up against this "development or not" question 20 years ago when we bought our current house. It was at the time two flats, and we wanted to convert it back into one house.

    The council were quite useless at providing information so I went independent. The relevant legislation says (something like), "For the avoidance of doubt, splitting one dwelling into two *is* development.", but of course left the opposite case completely up in the air.

    Happily we managed to find a test case which someone had brought, where it was ruled that joining two dwellings into one is not development, so we were able to keep the council quite out of it.

  13. Someone needs to invent air conditioning that does not require holes in the wall for air circulation. You can buy portable air heaters, we need portable air coolers.

  14. I suspect all planning legislation is crazy. I was told I had to supply a photograph of a non-existent painted fence, or the planning application wouldn't be considered. Oddly, the local fencing companies wouldn't allow me to paint one of their products in order to photograph it. I had to drive around town looking for a similar-coloured, similar-style fence to photograph...

    1. One new one been put up next to us and it not so much when it’s running more when it’s on or off if the wind is blowing. We get a high pitched sound which is extremely annoying and the unit is in our face every time we enter our garden. And can’t sit on our patio as a result. People have no thought or respect on the impact of these things before installing. Perhaps it would be neighbourly to discuss plans of work that will impact on neighbours. Bit it seems we live in a “me” world now.

    2. That sounds odd. Obviously we made sure what we installed was quiet in the first place!

  15. Inconsiderate neighbours put up a unit opposite our patio, eyesore comes to mind, also opposite our bedroom. It makes a high pitched noise whether on or off when wind blows through the fan. Although not VERY loud it’s extremely annoying when sitting outside. We were not approached by our neighbours and when we approached them when it was being installed, to ask if they could reposition it elsewhere, they scuttled indoors. Why can’t people be more neighbourly.. I have come to the conclusion that people have no thought/respect or even care what impact things can have on others. We live in a “ME” world I fear now. Upset and disgruntled...😩

    1. If it loses it's gas (because the nuts have loosened)then it will stop working. When they replace it they might consider putting it somewhere more considerate.

    2. If it was within the last 4 years, just call/email the council asking if they have planning permission for them :-)

    3. If it loses it's gas (because the nuts have loosened)then it will stop working. When they replace it they might consider putting it somewhere more considerate.

  16. I wonder if the 'heating only' restriction is because in the summer the neighbours will have open windows.

  17. What kind of temperature air is emitted from these outdoor compressor units? My neighbour has installed a 6kw mitsubishi air con unit within 1.8m of 2 or our opening windows. I have concerns over it pumping hot air into our house. Do you think this could be a problem. The unit is only 25cm from the boundary line, facing the side of our house.

  18. I've had a 3.5kw unit installed for 15yrs. Never needed planning permission.

    1. In the UK, you do need planning permission for an air conditioning unit that cools.

      The fact you have not been caught does not change that.
      If you manage 4 years without being caught you will be OK though.
      I had mind for 3½ years before someone reported it and I had to get planning permission.

  19. Unreal - with climate change our summers are getting extremely hot. From government reports one of the major risk factors is that we as a country aren't equipped to cope with the heat.

    The most efficient systems are split, they are far better for the environment. Neighbour should consult each other but eventually every house is going to need cooling, just like it needs heating. The rules need to change.

    I'm thankful that companies have started selling dual hose units the UK. We can just drill 2 6 inch holes into each room and use these units. Far cheaper, albeit, louder and takes up more space.

    The whole objection system really needs to focus on improving energy efficiency. Anything that does that needs to be prioritized. Things looking ugly is a non issue. Noise is an issue due to sleep disturbance, but typically studies show that white noise is beneficial for sleep.

    1. @Drush - I've been looking recently and only found the odd (sold out) dual hose unit on Amazon. I don't suppose you're able to recall which companies you've seen selling the dual hose?


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