I'm a Which? air-con expert - here are 5 things I would never do
Alison has worked at Which? for more than 10 years and has tested a wide range of baby products, home appliances, tech devices and gadgets.
Air conditioners aren't the cheapest appliances but they can make a huge difference to your living space, especially during heatwaves.
We've lab -ested 45 air conditioners, examining the cooling speed and consistency of each one, plus airflow distribution, ease of use and noise levels.
Whether you're considering buying an air conditioner or you've already got one, these are the crucial tips I've learned from our air conditioner tests, to help you make the most of it.
Best air conditioners: jump straight to our test results to see which AC units are most efficient and effective
1. Not check the recommended room size first
We look for air conditioners that can quickly deliver even, comfortable temperatures throughout a room. But air conditioners come in different shapes and sizes, and not all are suitable for every space.
To ensure you don't waste money or have an underpowered air-con unit, I would always check the recommended room size. Otherwise, your air conditioner could end up using more electricity to keep your home cool.
There's a simple formula to work out whether an air conditioner will be suitable for your home: multiply your room's dimensions in feet by five to find the BTU (British Thermal Unit).
So if your room is 15 feet long, 10 feet wide and 8 feet high, you would need a 6,000 BTU unit. Typically 5,000-8,000 BTUs are adequate for most living rooms or bedrooms.
2. Go for the most expensive option
Just because it costs more, doesn't necessarily mean it's better. Our tests show that the most expensive models aren't always the best, and some mean you'll be paying for features you simply won’t use.
It's not just the initial outlay either. It's important to consider running costs. The cheapest AC we tested cost about 17p per hour to run, and the priciest 31p per hour.
Our tests look for the most energy-efficient air conditioners that cool quickly, so you don't have to have it turned on for as long.
Check out our air conditioner reviews to compare the approximate running cost per hour on maximum settings, and make sure to avoid dodgy air conditioners sold by scammers.
Should you buy an air conditioner or an electric fan this summer? - our experts weigh in
3. Leave water sitting in it
While your air conditioner is working away to keep you cool, it collects water.
That water is stored in a warm, dark environment, which creates the perfect breeding ground for bacteria and mould spores.
When you're using it regularly, make sure to drain the unit every few weeks, and definitely drain it fully before putting it away for the winter.
Otherwise, that bad, slightly musty smell coming from your air-con unit could be mould that's being released into the air.
4. Let dirt or dust build up on the filter and fan
No matter how hard we try to keep our homes clean, dirt and dust are inevitable and, if you've got an AC unit running, it will build up on the filter and fan.
Clogged filters and fans force your air conditioner to work far harder than necessary, so it costs more to run and it does a poorer job.
Not to mention, any dust, pollen and dander stored inside can be released back into the air, which can make you feel sick.
Vacuum the filter or clean it gently with warm soapy water and a soft dry cloth.
5. Dispose of an old one incorrectly
Similar to fridges, portable AC units contain chemicals – so if it’s disposed of incorrectly, harmful greenhouse gases can be released into the air.
We’d always recommend referring to your local council's sites to find the safest way to dispose of your old air-con unit.
See how to correctly recycle your electrical items for more.
