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. But air conditioners come in different shapes and sizes, and not all are suitable for every space. 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.