Unlike basic desk fans, which have no cooling effect on the ambient room air temperature, evaporative air coolers do actually cool the air, perhaps not as well or as quick as air conditioning, but they will still reduce the air temperature by several degrees and can be a useful compromise over full blown air conditioning in expense, practicality and running costs.
An evaporative air cooler is far more effective than a fan in actually cooling a room, it is not quite as effective as full air conditioning. There are many types of evaporative air cooler available, each commanding their own prices, and range from small personal desktop units to free standing full sized lcd controlled room models which can cool down an entire living area or bedroom
Evaporative Air Coolers, use cold tap water which is circulated through a special ionised honeycomb grid. As air is pushed through the special honeycomb the cooling effect of the circulating cold water reduces the air temperature, resulting in air emerging which is cooler than the surrounding air. The effects of this can be further enhanced simply by using a mixture of ice cubes and cold water, some models also come with dedicated ice blocks, similar to those used in chilled food carrying bags. These chemical ice blocks are placed in a domestic freezer for a few hours to freeze, and then are inserted into the air cooler where they remain effective for upto several hours of use.
Evaporative Air Coolers are much cheaper to run than full sized air conditioners and can be just as effective in domestic households during very hot weather, they are also much quieter in use than portable air conditioners making them ideal for all night use in bedrooms, some of the more expensive units also come with built in air and pollen filters and additional air ionisation all of which may be of great benefit in bringing relief to asthma and hay fever suffers.
The main drawback of these air coolers, is of course, refilling them with water every few hours, and refreezing the ice packs every several hours, although of course buying additional ice packs to freeze whilst the main set is in use is, of course, a very cheap option which will enable 24/7 use.
In respect of running costs, Evaporative Air coolers will cost around 2p – 4p per hour to run, at current UK Electricity prices, depending on the model and features.