Built-in casters allow you to easily move the unit to any room in the house with a simple push, where the compact and upright design allows it to fit anywhere without taking up too much space. You'll be able to set between high, medium or low speed settings to maximise your comfort and adjust the fan to redirect cool air across angles of the room. This is described as being perfect for keeping conservatories, bedrooms, home gyms and offices cool and fresh.

It humidifies while it cools your personal breathing space so you can stay cool and breathe moist, humid air wherever the weather is hot and muggy-day or night. BTUs make this unit ideal for cooling areas up to 22 squares metres, it's also A energy rated so no need to worry about sky high energy bills either. But they send the humidity of that air up considerably, and this cancels out the benefits of the cooling effect when it is very hot.

Portable air conditioners are rated in British Thermal Units (BTUs) the higher the BTU, the larger room it can dispense cool air for, anything below 8,000 BTU is likely best for a small room. Let’s work on the assumption that it would be able to get the same 4ºC drop no matter what the ambient temperature was. If you believed the ads, you’d be forgiven for thinking you’re going to get frostbite if you sit too close. Blowing damp air into your PC would be dangerous, potentially expensive, and would only gain you 4ºC at best.

The Chillmax Air Pure Chill gives you the best features of both fans and an air conditioner in one, compact unit that’s also a night light.Designed specially to fit, easily into your Chillmax Air cooler, you can simply swap out the old filter for this new one and you're ready to go! Chillmax Air Pure Chill turns water, via a special, silver-infused filter and specially designed diffuser, into a fine mist of cool, refreshing air circulated by a fan with three speed settings. Indeed, you may have seen weather forecasts where they give the actual temperature and the ‘feels like’ equivalent – that’s a reference to the ‘ Heat Index’, which takes into account the effect of the %RH. The JML ChillMax Air Personal Space Air Cooler and Humidifier doesn’t use chemicals or toxic coolants.

The jack plug that goes into the Chillmax is quite stubby and doesn’t go into the socket very far, so it is easy to dislodge it. Chillmax Air's compact and lightweight design means you can enjoy cool fresh air anywhere from the bedside to the office. None of the conclusions I arrived at were influenced by any other sources – I didn’t look it up first, nor have I had any inclination to do so since I first wrote the article.

Anything below 8,000 is likely only going to cool a small/personal space, whereas 9 -12,000 BTU’s can usually cool up to 25 square metres. The working principle is identical, except that the larger the surface area of water, and the greater the airflow over that water, then the greater will be the possible drop in temperature at the front end (and the more moisture being pumped out to increase the humidity). I fired up my trusty data logger and left it in front of my desk fan for 30 minutes for the control data.