Jumping onto a bit of a hobby horse of mine as summer is coming, and that’s the vexed issue of air conditioning in the domestic home.

The UK is not generally considered to be hot enough to need air conditioning in houses as a routine thing to be included by builders or home improvers, and the need for air-con in the home is reduced by the fact that in the “before times”, people spent so much time in someone else’s building while working.

Yet, the domestic home, especially when well insulated, can be really uncomfortably hot for several months of the year.

Now that many more people are working from home, most of the time at the moment, if less in the near future, and on a hot stuffy day are probably wishing they were back in the air-conditioned office again.

I find it very difficult to concentrate on hot muggy days, and many years ago when living in a sun-facing flat that turned into a solar cooker in the afternoons, I bought a portable air-conditioner. I was slightly lucky, as many years previously, I used to sell them when working for a certain high street chain of electrical goods retailers, so I was already familiar with the concept of the device.

I have often told friends about these things and still spent summers listening to them complain about the heat, and so, I am going to tell you to see if you can afford to buy one.

Air con unit at ianVisits towers

A reasonable portable air-conditioner can cost £300-£400, which is a big upfront cost, but if you assume it lasts a decade, then that’s £30-£40 a year for the comfort of a cool home to live in every summer.

The portable units are rarely powerful enough to do more than cool down a single large room, so living rooms tend to be the best place for them for most people. They are also somewhat noisy, so bedrooms are pretty much out of consideration anyway.

(professionally installed air conditioners put the big noisy bit outside the building)

The key constraint but also the most important benefit to look for though is to buy one that has a large hose to hang out of the window.

While the hose is a nuisance, it’s vitally important that you buy one with a hose.

The cheap air cooler units that don’t need a hose cool the air by cooling water or being filled with ice cubes – evaporative coolers. Yes, it’s nice while in front of the fan, but the room itself doesn’t get noticeably cooler.

A hose based air conditioner extracts heat from the room and dumps it outside, so the amount of latent heat in the room drops considerably. It also dehumidifies the room, and that’s the big difference between air-conditioning and air-cooling. For many people, the humidity is as bad a problem as the heat.

You can hang the hose out of the window, but I found that a window plate that can be attached to the end of the hose makes putting it in the gap of an open window very convenient, and now I have a flat with balcony doors, it slots into the door gap instead.

Most units these days come with timers, so you can set it to come on automatically an hour or so before you come home in the evenings if needed.


Undeniably, they’re NOISY. You’re not going to watch the telly and have the air conditioner switched on at the same time. But if you’ve cooled the room down already, even on a really hot day it can take a few hours to warm back up, so ideal for evening telly watching.

I have to turn it off if taking a phone call.

They’re going to raise your electricity bill, and depending on how your electricity is generated, there’s an environmental impact.

The fat hose limits where they can be placed – they have to be next to a window/door, which can be inconvenient.

You’ll probably want to put it away somewhere in winter.


It feels lovely!

You can think clearly in the middle of a hot day.

I find the noise of the air-con unit can be oddly relaxing as it’s a constant white noise compared to intermittent noises from outside.

Many units include a dehumidifier only option so they can be of use to people with damp problems in the winter months.

Buying options

There are plenty of companies that sell portable air conditioners, and I can’t readily recommend this unit or that unit, as while I’ve owned two, that’s not enough to compare with what’s on the market today.

Candidly, most of the ones you can find online seem pretty much the same, some vary a bit in cooling capability (BTU) and noise levels, but I really wouldn’t stress too much over minor differences.

These are the sorts of things you want to be looking for (affiliate link), and comes with the extractor hose and the window plate attachment in the price. Your local electrical retailer may have one, but try to get it delivered, as they’re quite heavy.

I made the mistake of collecting one from a shop once, never again.

It is, however, no exaggeration to say that it’s probably the best £400 I’ve ever spent.


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  1. Yuriy says:

    This is my first summer with a portable aircon. If your windows open outwards, standard seals for the hose are not going to work well, so the best option I found is ordering a sheet of clear plastic cut to size that you can velcro over your window pane along the edges. Some services, e.g. cutmyplastic.co.uk will also a cutout for the hose so you don’t have to do it yourself risking to crack the plastic.

    That is another £50-80 on the top though. A much cheaper but less aesthetic solution is doing the same but with a piece of cardboard.

  2. Brian Butterworth says:

    Good points Ian.

    It’s 28.9C in my Office room right now, and that’s with the aircon on in the next room venting that room down to 26.5C. And that’s why my new, cooler PC.

    The best thing to deal with the noise and TV is subtitles. Almost all TV UK shows have them both on TV and online. Or, watch something Scandinavian and that will have massive in-vision ones.

    To get over the guilt of needing aircon, and I do because I live in a wonderfully insulated building with huge west-facing windows and a massive glass balcony, I’m using Pure Planet’s 11% solar, 89% wind service so I’m carbon free!

    • MiaM says:

      A big reason for your office room getting so hot is as Ghostface and Alistar have pointet out, the negative pressure. You will both get bad cooling and excessive electricity consumption.

      Apparently there are portable air cons with two hoses, intake and outlet for the “hot” side, which would be much better. They seem hard to find though. For anyone a bit handy with tinkering it might be worth trying to separate the two air flows in a single hose portable air con. You might need an additional fan thogh as the two flows might share a single fan .

      Back in the days the italian manufacturer Ariagel made portable air cons which were true split systems. A flexible hose went between the indoor and outdoor units. The indoor unit were about as noisy as the combination of a noisy fridge/freezer and a decent fan, while the outdoor unit did make a sound similar to a swamp boat. There were even versions of them with selectable heat/cool modes for usage as a way more efficient electrical heater than the regular resitive heating used in for example space heaters. I assume it became impossible to produce those units in accordance to regulations re risk of gas leakage (through wear or accidental puncture of the hose).

      IMHO it would be great if the electric appliacne stores in Europe started selling the North American style window units even if they don’t fit european windows. They are almost as efficient as a mini split but requires no refrigeration knowledge/skills/authorisation to install. Anyone who are able to cobble up something that fills the gap between a window AC and an open window will be able to run one of those.

      For someone who aren’t allowed to permanently install a mini split system it might actually be worth making something (say a piece of marine grade plywood perhaps?) that fits in a window opening and has the outdoor and indoor units for a mini split system mounted on each side. If there is enough room to wiggle it around through the house you might even be able to have a refrigeration tech install everything on it at the refrigeration techs facilities, thus avoiding the fee of having a tech come to your house.

      For anyone who are able to have a mini split system installed, go for that even if you plan on moving out in a few years. They are way more silent and way more efficient, and in the autumn and spring they might be cheaper at heating your home than your existing heating system.

      The simplicity of the single hose portable air cons is great selling point though.

    • Zoe Topsfield says:

      Ex London girl who lives in Los Angeles. I started avoiding visiting my dad in summer because his spare room upstairs was just an oven. I’ve been thinking for a while that the uk needs to start doing HVAC for homes. An interim solution that we use here in LA for when there isn’t standard HVAC is the “mini split”. Unit installed on a wall with a very small pipe (maybe 4 cm) that runs outside to a unit. It will only do spaces the cold air can reach but much more powerful and quieter than the stand alone outfits. Yes pricier. Totally worth it. I’m trying to get my sister in France to find them there.

  3. Annabel Smyth says:

    I do realise that it can get uncomfortably hot these days, what with global warming and all, but really, the environmental impact of air-conditioning is such that I don’t really think anyone should have it unless there is a medical need.

    • Ben says:

      Wholeheartedly agree! Not to mention the fact that aircon increases the temperature of the surrounding city…

    • Total says:

      Now make the same comment for heating.

      Not everybody lives in the same climate as you do.

  4. Ghostface1701 says:

    I have a portable unit too, and I find it a huge benefit this time of year. However, there is one main inefficiency: The hot air they pump outside via the hose leaves your home with negative air pressure, which equalises by… drawing in air from outside. Whether it’s through air vents, or under your front door, you pull in more warm air for your A/C to cool. A unit built-in to your home will end up cheaper and more effective in the long run, but we tend not to do those here.

    Also, there’s a very humid level of Hell reserved for people who run A/C, but also open all their doors and windows.

  5. Alistair James Twiname says:

    If you are thinking about a decade of ownership, you should really look at a built in unit.. that can also be used to heat your home very efficiently. As for why these are terrible, the wonderfully geeky technology connections has this guide. https://youtu.be/_-mBeYC2KGc

    • ianVisits says:

      The downside of built-in units is that I move more often than once a decade, so the 10-fold increase in cost is much much harder to justify.

    • Yuriy Akopov says:

      Units like that are mostly impossible to fit in leasehold properties, which most flats in England are.

      If you live in a freehold house, that is of course a better solution.

  6. Bruce Wayne says:

    Embrace the heat 😀 lol….. keep the blinds closed, dont open the windows when the sun is shining at the window

    A strange tip for sleeping at night is to have ambient rain sounds that play for around 45 mins on spotify and sometimes youtube or this https://rainymood.com/

    Give it a whirl… let me know your thoughts.

    PS Great post once again Ian, i dont know what id do without you and Diamond Geezer

    • JP says:

      I wholeheartedly concur sir save for the caveat that I find our genial host’s posts more palatable and less distressing than when I am pulled up short by the scare that people are actually concerned by such drudgery as occasionally discussed in the other place.

      I’m trying not to be too sharp but I think it’s fair to say that Ian’s version of life has more sunshine and clouds with silver linings than t’other’s sometime dips into cloud-seeded downpours of acid rain.

      Both equally give the grey cells a joyful run for their money though which is why I too enjoy indulging.

  7. Mr.G says:

    For about 3-5K you can get a whole house inverter type A/C fitted with small units or cassettes in each room. These can cool, heat, dehumidify, make toast on demand and are much better than those portable units that have a hose and a water tank to empty.

  8. Chz says:

    I live in a 1970s concrete-walled flat, and while there are maybe 4-5 days of the year that get uncomfortably warm they’re hardly worth the fuss of an AC unit. That being said, I grew up in Toronto; where the humidity rises in lockstep with the heat. It is never as hot as home here, as the truly hot days are always Saharan winds and dry as a bone. I’ve little trouble with dry heat until it hits 35 or so, it’s 26 and humid that bugs me and I have a dehumidifier for that. A good dehumidifier can process the entire house, given time, and doesn’t have the pressure issues of forced AC. It doesn’t cool the air, but it feels cooler.

    • Mk says:

      As someone from the Waikato, New Zealand, a similarly humid place, I can concur that 29 degrees and humid is utterly horrendous and makes London’s heatwaves pale in comparison. The only way out of the muggy heat is the beach or a pool. Failing that — the bath.

    • SteveP says:

      I lived in Toronto back in the 1980s and I went one summer without AC and it was brutal. Problem was the windows on my flat were vertical casements with thin metal frames, and the typical AC units didn’t fit. But fortunately, someone moved out and sold me theirs. Unfortunately, they were heavy smokers. I sat it in the bath and sprayed it with kitchen cleaner which ran off brown… ugh.

      It soldiered on for years though. There was one wire that would burn out and an AC tech came and showed me how to upgrade it. He also told me to take it to the car wash once a year and blast the fins with the high pressure hose! Just don’t get the electrics too wet – but as he pointed out, they are designed for outdoor use

  9. MilesT says:

    Technology connections channel on YouTube has recently published several videos on heat pumps including air conditioners. And evaporative coolers. Not too US centric and it helps to know the science

  10. Paul D. says:

    I have long had a ceiling fan in my south facing living room, it has three speeds and does a good job at ramming speed in those rare very hot and humid days, its not too noisy either.

  11. SteveP says:

    I bought a similar machine at Maplin (remember Maplin?) years ago when they discounted them in the autumn – I think it was £99

    It worked pretty well and certainly was appreciated in our various 35C “it never gets hot here” summers (much like our “it never snows here” winters – when it actually snows almost every winter…)

    The thing about “one-hose” AC units is that their “makeup air” has to be sourced from the same room, so for every cubic/ft/metre of hot air exhausted, it will suck in an equal amount of air from somewhere else (other rooms, outside, etc.) That’s physics. So the efficiency is reduced and you will note the hose gets super-hot as it is essentially concentrating the heat and expelling very hot air. That hose should be as short as possible and ideally insulated (you can buy duct insulation for a few quid)

    Better are the units with two hoses, which should be located apart from each other, but those seem to be rare. The best solution, IMO, would be for someone to offer a small mini-split heat pump with flexible armoured hoses that could sit outside with the cooling unit inside. There are actually window-hung units, but the UK seems to not offer any sort of window AC as you see in every NYC apartment. Heat pumps are efficient at both cooling and heating (bonus)


  12. hund says:

    I hate the heat and hanker after an air conditioner but worry it is antisocial as I will be pumping heat out to the flats above me. That, and the environmental costs, have so far stopped me buying. It would be good if London, and other cities, had cool places for the elderly to go.

  13. Gill says:

    Working from home for 12-hour shifts was impossible in the heat last summer, especially as I couldn’t then recuperate in my too-hot bedroom at night! I invested in two air-con units by Famgizmo, one for upstairs and one for downstairs: https://amzn.to/3gt64yv (eco version here https://tinyurl.com/2ra42kcd. I use them only on really hot days and nights. I’m a light sleeper, but sleep really well with it on nighttime mode – once the desired temperature has been reached, it drops mode to a pleasant hum that doesn’t disturb me at all – and certainly much less than the traffic noise I’d have to endure if I had the windows open. I take the precaution of wearing an eye mask so my eyes don’t get too dry (I wear contact lenses by day). I bought a kit to velcro a zip-up nylon window shield to my outwards-opening window, but it was ugly and didn’t work well. The air-con still works fine without.

  14. Peter Davies says:

    When thinking about buying an air conditioner, long term, it doesn’t make too much sense to be put off by worrying about the extra grid CO2 emissions.

    The days when an air conditioner would mainly be used are clear hot sunny days, and these are exactly those days when solar PV systems generate the most output. Putting one on the roof would be ideal. But even if you don’t, there is almost certainly more solar PV generation on such clear days than the total UK air conditioning load.

    At the moment, use of an air conditioner will increase the generation from fossil fuels. But, as total electricity demand increases, more solar (and a huge amount of offshore wind) will be installed. Solar with batteries would be best, as the air conditioning load extends a little into the evening. Eventually, there will be more solar on sunny days that the grid can cope with.

    In other words, air conditioning load is matched by solar generation now, though not the slight overhang into the evening. In the future grid batteries or solar farm batteries will also cover the overhang.

  15. john says:

    Sleeping in hot humid London weather is my problem. Putting an individual air conditioner in a flat in a listed building is problematic and often noisey, so I have a homemade portable solution involving a 6 or 9 inch fan blowing air through a 6 or 9 inch hole cut into the side or the lid of a large plastic storage box. The air leaves through 2 or 3 smaller holes on the opposite side/end of the box. On a hot evening, I put it in the bedroom, take 6 to 8 bottles/containers of water frozen in the freezer during the day, put them in the box, put the lid on the box, place the fan in position, turn it on and have a good night’s sleep.

  16. Lizebeth says:

    Having grown up in Manhattan, I cannot understand why someone in the UK doesn’t make a killing on window-hung air conditioners? Of course, local Councils would be prompt to forbid these as not conforming to building regs— but why is a hose hanging out your window any prettier? I inherited an old portable unit with my Flat, and if I place it close to my bedroom window, it provides instant, if temporary, bliss. But this means that I (who weigh 40kg) have to wrestle it (20kg) it from another room where it’s stored. So far I haven’t found any permanent way to cool this room. Any ideas out there??

    • SteveP says:

      Anything “temporary” is usually acceptable – well, if it is a “horse box” that is 🙂

  17. Total says:

    If you can, you must get a window-hung unit. They are much more efficient and effective than the portable ones. The hot part of the AC stays outside, and all that comes in is cold air. There’s no negative pressure issue. They’re much cheaper, as well (about £120 for a single room one).

    Wait (goes and checks Amazon UK): you don’t have them there, do you? Good lord, that’s appalling.

  18. John Leach says:

    I had split air conditioning fitted three years ago. I tried the portable ones first but noisy and inconvenient. The units I have now have the bit that does all the work outside of the house and I have quite running wall units inside. Worked by remote control they also can be used for heating in winter.
    Go for it do not bother with the portable ones.

    • ianVisits says:

      If you own your own home and don’t live in a block of flats with restrictions on attaching equipment to the outside wall, I would agree with you — but in London, that’s a minority of people.

  19. Sarah Johnson says:

    May I recommend blinds OUTSIDE your windows? Keeping the heat off the glass helps a lot. Then you have blinds INSIDE the windows to stop what gets through from spreading into the room. I also have a canope over my patio to keep the sun off the blinds off the windows off the blinds. Then you turn on the ceiling fan full blast. The above all require out of pocket expenses and installation and some maintenance, but they are pounds cheaper than air conditioning. When they don’t do the job, take your computer to the library and use their air conditioning.

    • Tara says:

      I tried this. My challenge is the windows open outwards, which is true of all places I’ve lived. Therefore, I only have the reflective blinds on the inside. I’m going to try just popping one outside the middle unopenable pane,in the hope that that still makes a difference.

  20. tops says:

    “Call Freephone Cucumber quickly! Woosh!”

  21. Benjamin says:

    For those worried about air conditioning and climate change the reality is well installed building air conditioning is actually a good solution.

    An air conditioner is just an air source heat pump. So long as you can run it *backwards* and pump heat from the outside to the inside as well on the days you need that it’s one of the most efficient ways of using electricity for heating.

    The daft thing to be doing now is installing single direction systems, spending a good chunk of money to get a highly efficient form of heating but using it only to heat the outside is… Odd?

    So look out for reversible systems, as we move away from gas heating you’re probably going to be seeing a lot more of them.

  22. Nick Frost says:

    Can I make a case for using them in bedrooms, after all?

    Yes, you have to lug the thing from the living room (easy in a flat, not so much in a house).

    Yes, it’ll probably get in the way.

    Yes, it means having to construct a makeshift triple curtain out of throws and dressing gowns to block the light you’re now letting in.

    Yes, it’s noisy.


    You absolutely get used to all of these things (even the noise, trust me).

    And best of all: you get a great night’s sleep.

    Best £280 I ever spent.

    • T says:

      May I suggest a “temporary black-out” blind/material with a silver reflective back. I’d get one where the velcro uses M3 glue or buy Command strips seperately,to stick to the window frame. You can cut it around the hose to stop the excess light coming into the room. No damage to rented flat and costs less than £20 depending on window size and when in the year you purchase it. Summer months are slightly more expensive.

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