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Who's in the UK and has caved in and bought air conditioning?

stanto — Fri, 26 Jun 2026 21:21:41 GMT

I picked up something like this about three years ago. No regrets.

Though I can't help but feel like I'm also adding to the climate problem.

RE: Who's in the UK and has caved in and bought air conditioning?

obones — Tue, 30 Jun 2026 08:39:38 GMT

Is that a "closed circuit" thing? I mean, during the winter, does it circulates the house air while heating it? Or does it take outside (very cold) air, heats it, blows it into rooms, effectively pushing out ambiant air out of the rooms?

From an efficiency point of view, it'd be better to have a closed circuit with a "calories exchanger" but I'm not sure how your system is designed.

RE: Who's in the UK and has caved in and bought air conditioning?

stanto — Mon, 29 Jun 2026 21:32:30 GMT

Same. There are vents everywhere, and yet, no airflow. We used to have the hot air for heating and a separate water boiler for hot water.

We now have a combi condenser boiler, thankfully, but the old setup is still there. Perhaps I should do as you're suggesting and hook up the aircon to it, since the heater unit resides in the kitchen already, I could exhaust the heat through the cooker hob unit... maybe, its a bit greasy, something to ponder.

RE: Who's in the UK and has caved in and bought air conditioning?

Fred27 — Mon, 29 Jun 2026 14:13:58 GMT

My house has hot air heating - very much a 60s thing in the UK although I'm aware it's more common on other countries. I've been tempted to see if I could modify things to blow cooled air around the house when it's really hot, but have resisted so far.

RE: Who's in the UK and has caved in and bought air conditioning?

stanto — Sun, 28 Jun 2026 23:30:36 GMT

To add to the other valid points, when you rent landlords often do the bare minimum, and don't want to be responsible for maintaining white goods, especially in an unfurnished property, and that would also include maintenance of an aircon unit. Then standalone units to be effective require modifying the property in some way, and landlords get upset when you're not "using their home as a home", despite the right to be left alone. Weird ego's get in the way.

Having the aircon unit I have easily adds £5/day when it runs all day to the electricity bill, doing that causes the electricity company to go "oh, you're using a lot of electricity per month! we need to re-assess how much you pay on your bills! we're upping your monthly payment!" and it isn't until a few months later, where they go "oh you're paying too much, we're reducing your monthly bill" and it ends up in a cycle, because with the electricity you kinda pay what you *might* use and it tries to estimate the cost. A spike skews that, which puts people off.

RE: Who's in the UK and has caved in and bought air conditioning?

ralphjy — Sun, 28 Jun 2026 04:47:31 GMT

Wouldn't it still reflect off the aluminium backplate onto the rear of the panel ?

I could blow the air behind the panels, but to get his efficiency he was actually bonding metal angle irons to the back of the panels which blocks the backside..

Is this with forced air or just passive ventilation ?

It's forced air with window fans. Passive ventilation doesn't work for me in the amount of time available at night unless there is a huge differential. One of the differences between summer and winter is that the large capacitors of the attic and crawlspace are hot in the summer and cold in the winter, so that aids the cool down in the winter. I do have a solar attic vent, but that doesn't run at night.

What was the break even point ?

It was about 24 MWh, so about 4 1/2 years.

RE: Who's in the UK and has caved in and bought air conditioning?

beacon_dave — Sun, 28 Jun 2026 00:53:47 GMT

[quote userid="2238" url="~/members-area/f/forum/57067/who-s-in-the-uk-and-has-caved-in-and-bought-air-conditioning/236262"]I wouldn't have been able to do it with as much efficiency as he achieved because I have bi-facial glass panels, so I can't attach to the backside without compromising performance.[/quote]

White / aluminium fans ? 🙂

Wouldn't it still reflect off the aluminium backplate onto the rear of the panel ?

[quote userid="2238" url="~/members-area/f/forum/57067/who-s-in-the-uk-and-has-caved-in-and-bought-air-conditioning/236262"]I ventilate the house in the late evening[/quote]

Is this with forced air or just passive ventilation ? I'm surprised at the lack of passive cooling I'm getting here even with a 9C difference in temperature. In Winter time, that would have equalised in a matter of minutes.

[quote userid="2238" url="~/members-area/f/forum/57067/who-s-in-the-uk-and-has-caved-in-and-bought-air-conditioning/236262"]when we have extended hot days and overnight temps stay above 18 C - I can't cool the house enough to reduce the AC runtime[/quote]

When I made that comment I was thinking mainly about reducing bedroom temperature by about 10C for a decent night's sleep. So running a small AC unit for a few hours before bedtime after either solar charging a battery during the daytime or selling it back to the grid.

[quote userid="2238" url="~/members-area/f/forum/57067/who-s-in-the-uk-and-has-caved-in-and-bought-air-conditioning/236262"]The system just passed 46 MWh total, so I probably shouldn't complain too much.[/quote]

Congrats. What was the break even point ?

RE: Who's in the UK and has caved in and bought air conditioning?

ralphjy — Sat, 27 Jun 2026 23:01:26 GMT

Nice video. I considered adding fans early in the life of the system when I saw the thermal degradation in the summer. I wouldn't have been able to do it with as much efficiency as he achieved because I have bi-facial glass panels, so I can't attach to the backside without compromising performance.

My system is old enough now (8 1/2 years) and I am considerably older, so I wouldn't tackle that scale of project to try to improve it. Probably not worth the investment. I would have considered it to extend the life of the panels, but honestly in 20 years I probably won't care even if I'm still alive.

I ventilate the house in the late evening, so in general in the summer I can produce enough energy for the AC, but when we have extended hot days and overnight temps stay above 18 C - I can't cool the house enough to reduce the AC runtime.

The system just passed 46 MWh total, so I probably shouldn't complain too much.

RE: Who's in the UK and has caved in and bought air conditioning?

beacon_dave — Sat, 27 Jun 2026 19:09:38 GMT

Not fitted your fans yet ? 🙂

Do you REALLY get enough out of your solar panel?
https://www.youtube.com/watch?v=Mt9qLRN7JvA

But I'd imagine you could still harvest enough in summer with a modest solar setup even at reduced performance to run an AC setup ?

RE: Who's in the UK and has caved in and bought air conditioning?

ralphjy — Sat, 27 Jun 2026 18:34:26 GMT

Hope that you're able to stay cool. It's only gotten up to 39 C at my house so far this year. In 2021 around this time, the Pacific Northwest had a "heat dome" and Portland had 3 consecutive days above 40 C with the record high temp being 47 C. There were 123 heat related deaths in Oregon due to that event; 72 were in the Portland metro area. There has been a large effort to mitigate heat related deaths since then (cooling centers and AC for low income and elderly people) and so far this year there have only been 4 heat related deaths in the metro area. The world is definitely not prepared for climate change.

RE: Who's in the UK and has caved in and bought air conditioning?

dang74 — Sat, 27 Jun 2026 17:19:49 GMT

Wow.

RE: Who's in the UK and has caved in and bought air conditioning?

Jan Cumps — Sat, 27 Jun 2026 16:19:01 GMT

RE: Who's in the UK and has caved in and bought air conditioning?

Workshopshed — Sat, 27 Jun 2026 15:24:00 GMT

Seriously thinking about it

RE: Who's in the UK and has caved in and bought air conditioning?

ralphjy — Sat, 27 Jun 2026 15:18:57 GMT

Interesting data point is that for my solar system - summer is not when I get maximum dally energy production. Even with extended daylight hours the performance degradation due to high operating temperature means that when I need AC most, available energy is reduced.

I actually have to be careful using my mobile phone in bright sunlight when using the camera because it gets noticeably hot.

RE: Who's in the UK and has caved in and bought air conditioning?

beacon_dave — Sat, 27 Jun 2026 13:07:00 GMT

A custom attachment for a window vent with an insulated vent pipe and a custom attachment for the standalone aircon unit could work. Parametric models for 3D printing so you can adjust the overall dimensions, duct diameters and fixing positions.

I was also pondering if any readily available condenser radiators (automotive ?) could be used to DIY a system. Fit an appropriately-sized condenser radiator into the existing window vent opening with a fan mounted behind it, keeping the hot stuff outside, then an evaporator unit in the room with a fan cooling the room.

RE: Who's in the UK and has caved in and bought air conditioning?

beacon_dave — Sat, 27 Jun 2026 12:33:08 GMT

[quote userid="121623" url="~/members-area/f/forum/57067/who-s-in-the-uk-and-has-caved-in-and-bought-air-conditioning/236249"]Mostly I work in an internal insulated room (100mm of insulating foam board and plaster board cladding inside). That gives quite good insulation in either direction although it was intended to keep me warm in winter.[/quote]

I think insulation generally works as long as you don't have external windows that quickly heat the air up inside and trap it there.

[quote userid="121623" url="~/members-area/f/forum/57067/who-s-in-the-uk-and-has-caved-in-and-bought-air-conditioning/236249"]I installed a split unit about 10 years ago but the outside part couldn't cope with the Scottish weather and died after about 5 years.[/quote]

One of the reasons I was looking at indoor mono block units. Less efficient but then not exposed to the UK weather.

[quote userid="121623" url="~/members-area/f/forum/57067/who-s-in-the-uk-and-has-caved-in-and-bought-air-conditioning/236249"]Yesterday when I left work at 6pm the air temperature was 26C, when I got home (which is on the sea coast) at 6:20 ,it was misty and the air temperature was 18C - which is why we don't need air con at home (yet). (In London it was 36C).[/quote]

Down the road from you in NW England and I was pulling cables indoors in 33C all afternoon. Leaving at 4pm and office thermometer indicated 29C. (My colleagues thought I had completely lost it when I commented that it felt cool in there. 4C lower makes a big difference.)

Just as I was leaving, there was a thunderstorm and you could see the heavy rain instantly evaporating off the hot tarmac. It was like a dry ice fog effect on stage. Car thermometer said 30C.

Got home and the bedroom upstairs was reading 33C. Windows open for 8 hours and it dropped by 5C to 28C. Outside forecast was for 19C, so in theory appropriate designed ventilation should be able to make it more comfortable for sleeping.

I think though that there is a lot of heat trapped in the roof space that is very slow to release. Ridge tile vents might have helped there allowing for convection cooling.

RE: Who's in the UK and has caved in and bought air conditioning?

beacon_dave — Sat, 27 Jun 2026 11:03:43 GMT

I'd probably add 'architects' to that and bump it up the list with their 'form over function' mentality.

There are planning regulations that can impact installations; easy for architects to work with at design time but can be problematic for an owner to retrofit.

Also there doesn't appear to be much in the way of a standard form factor which allows you to replace an indoor unit with another without having to redecorate afterwards.

In the US I see a lot of sash windows with the mono block air conditioner unit wedged into it. Almost as easy to buy and set up as a microwave oven. Most of the houses I have lived in here in the UK though have had casement windows, with vertically-hinged opening panes or horizontally-hinged vents, so that approach doesn't work.

Likewise with portable units, there don't appear to be standardised ducts ready for you to plumb your vent pipe into, so you end up with a temporary duct running around the room and up a window to the nearest window vent.

Cost to install and maintain and cost of electricity to run in this country. Although improvements in solar + battery could change that now. Unlike with heating in Winter, in Summer you tend to have a lot of sun when you need the energy for cooling.

High density housing probably doesn't help either, can you imagine having your neighbours worn-out outdoor units rattling away either side of your open bedroom window all night long. Even the hum of a new unit will probably be enough to annoy some. Already happening with newly installed heat pumps.

The trend may be changing now with the push for air source heat pumps which can also be run in reverse for cooling. Was likely installed to replace the gas boiler but during hot spells, I could see people starting to use it for cooling if it is there as a setting. Planning regulations appear to be more relaxed for heat pumps.

It took a while for it to become the norm in vehicles over here. I don't use it much, just on the occasional very hot days.

The biggest factor is probably the variable UK weather though. (It is not unusual to have four seasons in one day. People even like to write songs / tunes about it ! ) Most houses in the UK have primarily been designed to keep the rain out, and only more recently to keep the heat in to reduce heating energy costs in Winter. Until recently, extreme heat hasn't really been that much of an issue to justify the expense of installing / running air conditioning.

RE: Who's in the UK and has caved in and bought air conditioning?

michaelkellett — Sat, 27 Jun 2026 08:45:26 GMT

I have a factory unit about 14 miles from my home in South West Scotland - about 300 miles North of London.

Mostly I work in an internal insulated room (100mm of insulating foam board and plaster board cladding inside). That gives quite good insulation in either direction although it was intended to keep me warm in winter.

I installed a split unit about 10 years ago but the outside part couldn't cope with the Scottish weather and died after about 5 years.

I replaced it with a small mobile unit which just has to pump the heat out from the insulated room into the bigger space. It works OK for our temperatures.

Yesterday when I left work at 6pm the air temperature was 26C, when I got home (which is on the sea coast) at 6:20 ,it was misty and the air temperature was 18C - which is why we don't need air con at home (yet). (In London it was 36C).

Air con is expensive to run in the UK because our electricity at retail prices is very expensive.

RE: Who's in the UK and has caved in and bought air conditioning?

shabaz — Sat, 27 Jun 2026 02:32:25 GMT

The buildings are different, it's not unusual to live in 100-year-old homes, so one is lucky if there's even good lighting and electrical connections in all the locations you want them; and existing ducting is almost unheard of. A lot of homes don't have the space for the outdoor units, and some really like their homes to be quiet. Some of it's also related to the energy mix, traditionally people used more gas in their homes perhaps (we still do), and a lot less electrical. And some of the reasons are cultural, air-con is seen as OTT, and some may not even ever switch it on in their vehicles.

The combination of all that meant that air-con was one of those technologies that just ended up not being adopted by residential consumers in the UK, whereas it's super-normal in the US.

RE: Who's in the UK and has caved in and bought air conditioning?

shabaz — Sat, 27 Jun 2026 02:17:25 GMT

Resisted it so far! But getting harder to ignore.

RE: Who's in the UK and has caved in and bought air conditioning?

mp2100 — Sat, 27 Jun 2026 01:00:41 GMT

. . . Because many homes don’t have AC there. And it’s much hotter this week than normal.
London was 87 F today and it’s at 51 N latitude.

RE: Who's in the UK and has caved in and bought air conditioning?

robogary — Sat, 27 Jun 2026 00:45:03 GMT

Why is air conditioning such an issue in the UK ?

RE: Who's in the UK and has caved in and bought air conditioning?

stanto — Sat, 27 Jun 2026 00:36:42 GMT

[quote userid="41967" url="~/members-area/f/forum/57067/who-s-in-the-uk-and-has-caved-in-and-bought-air-conditioning/236243"]Going to a split system would be the other way but then where to mount the outside unit.[/quote]

That's where the compromises come in, especially if you're renting.

[quote userid="41967" url="~/members-area/f/forum/57067/who-s-in-the-uk-and-has-caved-in-and-bought-air-conditioning/236243"]Also the duct couplings I've seen so far have been pretty poorly designed and loosen with the duct expanding due to the heat.[/quote]

This is also true.

Someone could make bank with a few little design tweaks that simply follow or make a sensible standard, even if it was for typical hvac.

RE: Who's in the UK and has caved in and bought air conditioning?

beacon_dave — Fri, 26 Jun 2026 22:21:11 GMT

I was wondering about insulated ducting. Also the duct couplings I've seen so far have been pretty poorly designed and loosen with the duct expanding due to the heat.

Getting a good seal to the window depending upon what sort of window you have can also be problematic.

The wall-mounted mono blocks I think have two ducts, one for air in and one for air out with a heat exchanger and then a blower that circulates the air in the room so no pressure issue.

I was also wondering about more modular duct based systems. If I could mount a mono block unit on a wall in another room for good exchange to the outside with short ducts for the hot stuff, then run two ducts to the bedroom via the ceiling to circulate the air indoors, then that could work. It also keeps the motor noise outside of the bedroom as well.

Going to a split system would be the other way but then where to mount the outside unit.

RE: Who's in the UK and has caved in and bought air conditioning?

stanto — Fri, 26 Jun 2026 21:51:26 GMT

[quote userid="41967" url="~/members-area/f/forum/57067/who-s-in-the-uk-and-has-caved-in-and-bought-air-conditioning/236241"]I've used the portable ones before at work and they tend to radiate the heat back into the room from the duct before the hot air gets out the window, so not very efficient at actually cooling the room.[/quote]

The meaco one came with a plastic, extending tube that you're meant to fit to the back of the air con unit. I don't use it, it radiates heat, and frankly the air flow is noisy.

I bought a tube like this:

Which, may be a bit overkill, but the heat is now mainly at the junction point between the tube and this, you get an adapter with the aircon unit, but with a thermal camera, it's only exhausted out the far end.

The unit itself gets generally a bit warm, but the unit does a good job at cooling. I suppose the only other wonderment is the whole "positive/negative pressure" from the air intake being indoors, but the temperature drop is so significantly noticeable it hasn't been a problem.