There is an old saying that it is far easier to warm up when its cold, than to cool down when its hot, and unless you are fortunate to live in a Country where hot summers are common, and air conditioning is installed into virtually every apartment and place of work, then you will probably be experiencing this first hand!. In Countries like the United Kingdom we are rarely geared up for long hot summers, and when those rare heatwaves strike loss of sleep during the night and loss of productive interest during the day begin to take their toll. So how can we cope with the heat of the day and the long sleepless humid nights.
Electric Fans, are the most common way in which we try and cool ourselves down and make the rooms we are in more comfortable. Portable Desk Fans are generally also the cheapest to buy and to run, although ceiling fans are becoming more popular in living areas and bedroom within households.
The biggest drawback of using Electric Fans, is that they do not actually cool the air itself or the room, and any feeling that the fan is actually cooling you is purely down to the movement of air across your skin. Whilst Desk Fans may bring some relief, during very hot or humid periods or when the room temperature is high, all you may succeed in doing is getting hot stagnant room air being blown into your face, and so the relief from using an Electric Fan may be limited and short-lived as the ambient room temperature increases.
Portable Electric Fans are available to two different types, Desk Fans, which by their description, sit on a desk or a table and pedestal fans, which are stand or tripod mounted and stand on the floor. Generally these types have two or three different speeds and can be set to sweep upto 180 degrees left to right automatically.
Ceiling Fans, are designed to be installed within the centre of the room and often replace a ceiling light, in fact many ceiling fans also have a built in decorative light or set of spot lights so they can serve a dual cooling / lighting purpose with the fan and light(s) being electrically switched independently of each other. Ceiling Fans are more expensive than desk fans and may require an Electrician to install them.
Ceiling fans, just like Desk Fans do not actually cool the air, although their blades are far wider and will sweep more air so the circulation effect within the room will be far more effective than portable desk fans. Ceiling fans tend to be far more quieter than portable desk fans, making them ideal for use in bedrooms or offices. Another advantage of ceiling fans is that they come with a wall mounted control unit, or remote control which not only allows the fan speed to be adjusted, but also allows the direction of the blades to be reversed, which allows some heat during the winter months to be directed back down into the room from roof to floor level and so helping to reduce heat loss trough the ceiling and recirculating the useful room heat during the winter months.
Evaporative Air Coolers
An evaporative air cooler is a device which is far more effective than a fan at actually cooling a room, but 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 floor standing full sized lcd controlled room models which can cool down an entire living area or bedroom.
Unlike basic desk fans, which have no cooling effect on the ambient room air temperature, evaporative air coolers do actually cool the air, not as well as air conditioning, but will reduce the air temperature by upto four or five degrees and can be a useful compromise over full blown air conditioning.
Evaporative Air Coolers, use cold tap water which is circulated through a special ionised honeycomb. As air is pushed through the 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 by replacing the tap water with a mixture of ice cubes and water, some models also come with dedicated ice packs, similar to those used in cool bags, these 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 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 than portable air conditioners making them ideal for all night use in bedrooms, some of the more expensive units also come with air and pollen filters and additional air ionisation all of which may be of great benefit to asthma and hay fever suffers. The main drawback 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. Evaporative Air coolers will cost around 2p – 4p per hour to run, at current UK Electricity prices, depending on the model
Portable Air Conditioners
Portable Air Conditioners are probably the most effective form of cooling down larger rooms, however often they are the most expensive to buy and run. Air conditioners use a compressor just like the one which is found in domestic fridge freezers, and air is circulated through a matrix which is cooled by refrigerant before being blown back into the room. Because the refrigerant is cooled to almost freezing point, the resulting air is often up to ten degrees colder than the ambient room temperature, making air conditioners the fastest and most effective method of cooling buildings.
Air Conditioners are available to two different types, there are fixed wall mounted air conditioning units which mount through the wall and the have the compressor unit on the outside of the building, and a matching vent / control unit on the inside wall where the cool air is exhausted into the room.
However, in domestic houses it is far more common to see self contained portable air conditioning units which are floor mounted and on casters to enable them to be moved from room to room. The main drawback with portable air conditioners, is that they tend to be very heavy, can be noisier than evaportative air coolers and desk fans and draw far more electricity than the other options, often as much as 750w to 1000w, translating into a real cost of about 10p to 15p per hour to run on many standard UK electricity tariffs.
Portable Air Conditioning units also require a tube, similar to that which is often used on tumble dryers to be exhausted to the outside and so they will require either a purpose built wall vent to be installed into the room, or the tube simply hung over an open window.
Portable air conditioners can often also contain a small heating element which can be used during the winter so the unit can form part of a dual purpose portable heating / cooling unit, sometimes air conditioning can be included as a feature of portable air source heat pumps.
