This year, after being told to work from home, I suddenly found myself setting up office in the only free space in my house which turned out to be the conservatory. I already had a desk and a decent chair, so I thought everything was in place... until the sun came out. In a conservatory on the west side of the house I was ok in the morning, but as soon as the sun hit the glass around lunch time the temperature inside suddenly went up from 22 (perfect office temperature) to 23, 24, 25... 28... and that's with the windows and door open!
At first I thought maybe I'd be back in my air conditioned office before the summer hit, but as we all know the global pandemic of 2020 just went on and on. By July I was enduring temperatures of up to 39C while trying to concentrate on my job as a systems analyst. Something had to be done. On a daily team Skype call, one of my colleagues mentioned that he'd seen a mini split air conditioner that could be installed without a professional installer. I was doubtful, as I know that the 'easy fit' air conditioners that are available are no longer legally allowed to be installed by someone who isn't a qualified 'F-gas' installer. I had a look on the Appliances Direct web site and found the thing he was talking about (electriq elQ-9WMINV 9000 BTU) and it turned out that because the gas used in it is propane, it's perfectly legal to install it yourself. After a bit of thought, I bought one for a total (including delivery and vat) of £444.97 and it arrived the next day.
Although it was specified as 'easy to install by a competent DIYer', the instructions were, frankly, baffling. The installation guide talked about features it didn't have, and buttons that didn't exist, but I decided to give it a go anyway. The delivery was two big boxes; one for the indoor unit and a bigger one for the outdoor unit. The steps I followed were:
The unit is 9000 BTU, and performs much better than a portable unit of the same rating, because it recycles air inside, instead of venting hot air out of a window. Venting air means that you need a window open, and even if you block off the gap in the window with something, the air that leaves the room has to be replaced from somewhere, so it gets pulled in from somewhere else. I found the cooling performance on the hottest day of the year to be ok, as long as I provided some shade from direct sunlight. Blinds inside helped, but the best thing was to provide shade outside using a garden parasol or even a white sheet hanging down outside the windows. With appropriate shade, the unit cooled my workspace easily to 21C, which combined with the dehumidifying effect, was more than enough to feel fresh but not too cold. The inside unit is really just a fan so noise wasn't a problem, although the outside unit can reach noise levels of about the same level as a microwave oven cooking so I was careful to put it in a place that wouldn't irritate my neighbours. It's important to note that because this system uses an inverter, the compressor outside isn't running at full power unless it really needs to. At most of its variable speeds, it's just making a quiet fan noise.
One of the benefits of this system is that in the winter you can use it as a very efficient heater. This is achieved by the system running in reverse, so it extracts heat from outside (even when it's freezing cold outside) and transfers it inside. This is quite hard to get my head around, but I think of it like my fridge that manages to throw heat out of the back even when it's cooling the inside to very cold temperatures. Somehow it finds that heat in the cold and concentrates it, ready to be expelled against my kitchen wall. Performance is pretty good, and even when it's frosty outside the unit blows air at about 30C. In slightly warmer temperatures of 10-15C outside, it manages to blow air at about 40C. this isn't as hot as an electric fan heater, but it blows a lot of air at this temperature so it warms a room really quickly.
I've not used it long enough to work out exact running costs, but the compressor runs at a maximum of 750 watts, and it easily outperforms a 3KW electric heater. Most of the time the compressor isn't running at full power, and for some of the day all that's running is the fan inside. As the same compressor is used for cooling, 750 watts is the maximum that could be used, and with a combination of shade and the unit set to provide a moderate air flow, the cooling function hardly ever seems to be running at full capacity.