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How much does it cost to run a portable air conditioner, and how quickly does it cool a room? [Updated with 2022 prices]

How much does it cost to run a portable air conditioner, and how quickly does it cool a room? [Updated with 2022 prices]

UPDATE: This was originally written back in 2021 and somehow since then, back then all we had to worry about was a pandemic. That's still a problem but we now also have war and a cost of living crisis. What a time to be alive. I have therefore updated this post with more accurate pricing, to reflect the astronomic price rise of electricity. This is accurate for May 2022.

With the temperatures continuing to soar and the Met Office issuing an extreme heat warning, many of us have been looking to buy a portable air conditioning unit.

If, like me, you are vaguely aware of these, you will know they cost a lot to run, they are loud, they are big and awkward to use with UK based windows.

This year, I finally caved and bought an Inventor Magic 12000BTU Portable Air Conditioner from Amazon, which is now out of stock.

Recommended Portable Air Conditioners

How much does a portable air conditioner cost to run?

The main concern with air conditioning is the cost to run it. The power consumption will vary depending on the cooling capacity of the unit. This typically ranges from 1Kw to 1.3kW for air-con units rated from 9000 to 12000 BTU.

My Inventor Magic is rated at 1350W per hour for cooling. Actual usage appears to vary between 1100W and 1300W, and this seems to average out at 1200W while it is running full blast.

Cost to run an air conditioner in 2022

I am currently with SO Energy which has a unit rate of 13.6476p/kWh (I chose them because of the cheap electricity due to me running a lot of computers). You can sign up for SO Energy here.

This then works out at 16.38p per hour to run, which seems quite cheap, really.

I left the struck-out text above just so we can all feel depressed about how cheap electricity was.

Various tariff examples:

  • 2021:
    • SO Energy: 13.6476p/kWh
  • 2022 (May, Variable Tariffs)
    • Bulb: 28.0203p per kWh
    • British Gas Standard Variable: 28.021p per kWh

SO Energy and EON Next won't provide variable tariff details as they are not taking new customers.

Based on the above prices, last year it was costing me 16.38p per hour to run and now it would cost 33.60p or a 105% price increase.

Last year I pointed out that running this by itself used up just as much electricity as the rest of my house and the costs will add up quickly, just twice as quickly this year.

My overall opinion hasn't changed about them, apart from that it costs twice as much. If you plan to leave one of these on all day, then you are in for a bad time when you get your energy statement. Of course, the air con will switch off when it reaches the desired temperature (and back on) so you may not be running it all the time.

Air conditioners were always expensive to run and being a tight-fisted northerner I would never run one all day. However, when it is painfully hot outside and my office is touching 30-degrees or my bedroom is 23+ degrees, I think spending 67p running an air-con for a couple of hours is still worth it. They are very noisy anyway so I'd prefer to have them running as little as possible.

How quickly does an air-con cool a room?

I am still testing it and have only just started keeping an eye on temps and times. Considering the current heatwave, I thought I’d get some content out sooner and add more accurate numbers over time.

In 2 hours 15 minutes, it used 2.5kW of energy and cooled my office from 27-degrees to 21-degrees. Subjectively it feels cooler, I think the cool air moving around the room makes it seem colder than it is. My office is 4.5m x 3.5m and is 2.5m high, so just shy of 30m3.

How loud are portable air conditioners?

Really quite loud. I don’t have an accurate sound meter, but using my phone, it reads 40-50db with the air-con just off to the side of me. The sound profile isn’t too bad, it is not high pitched and just sounds like a fan on high speed. I can cope with it switched on in the office, but there is not a chance in the world could I fall asleep with it on. I plan to cool my bedroom to something more pleasant and then switch it off when I go to sleep. I will resort to a quiet pedestal fan if it gets too hot in the night.

How large are air conditioning units?

They obviously vary a lot depending on their rating. The Inventor Magic 12000BTU is one of the higher-rated models out there and, therefore, physically large.

It is probably about as tall and wide as an under-counter fridge but less deep. It weighs 35KG, so it wasn’t all that fun carrying it up the stairs by myself. If you keep it on the same floor, it is not too bad as it is roller wheels on it.

How easy is it to fit a portable air conditioner hose through a UK uPVC window?

The Inventor Magic 12000BTU comes with a windows kit, but this appears to be for sash windows (the traditional windows that slide up).

I have uPVC windows that are top hung, which is therefore not compatible. There are various kits you can buy on Amazon, which are basically bits of cloth with zip and velcro that stick around the gaps in the window. From my brief experience with them, they are a bit rubbish, and I am very sceptical of the large number of Amazon reviews some of them have. Unfortunately, this seems about the best solution, certainly for temporary use.  It is far from ideal, and they are quite ugly, but it is what it is.

  • [Original Post] 20th July 2021
  • [Updated] 20th May 2022 – Reflecting increased energy prices.

Last update on 2023-03-30 / Affiliate links / Images from Amazon Product Advertising API


Saturday 10th of September 2022

I have a similar model. I cant believe I didn't know how to work out the cost before. Mines 1114w, Bulb is now 27.1p/kwh 1114 ÷ 1000 x 27.1 = 30.19p I had mine on way more than I needed, I'll certainly be more conscious next summer now knowing the price!

Ken Schoch

Sunday 24th of July 2022

I have bought a DeLonghi EM82 portable a/c for my static caravan which is like an oven on hot sunny days. It is vented out of the side of the caravan and the hose wrapped in insulating material. With all windows and curtains closed the unit can cool the interior at the rate of about 4 deg C per hour down to 18 C but it feels cooler as soon as it switched on. I don’t find it particularly noisy when in max cooling mode but I am not sure I could sleep with it on.