Frequently Asked Questions
How do portables air conditioners work?
The portable units in this section are all refrigerant devices and work on the same principle as professionally installed split systems that you see in offices and homes (a split system is one where you have an internal wall mounted unit connected by refrigerant pipework to an outside condensing unit that is usually bolted to a wall or on a roof). By using refrigerant the machine can produce chilled air very efficiently. The air coming out of these machines is usually between 5 and 10C (40F and 50F).
What is the difference between a refrigerant device and an evaporative cooler?
An evaporative cooler (see elsewhere on our site) has a tank inside that the user fills with water. This soaks a rotating membrane. A fan pulls air through this membrane and as it does so the water evaporates off and it is this action that causes cooling of the air. Evaporative coolers require a constant supply of fresh, low humidity air in order to operate. This means keeping windows and doors open to allow constant fresh air change. Whatever the conditions a refrigerant air conditioner will always produce cooler dryer air.
What are BTU's and KW's?
BTU's and KW's are different units of measure of heat (or cooling) energy. Here in the UK we always used to use British Thermal Units (BTU's) and often you will find heating and cooling equipment performance measured this way. On the continent they use the internationally recognised unit of Kilowatts (KW). There is a direct relationship between the two - 1KW is the equivalent of about 3400BTU. So a 9000BTU machine is a 2.6KW machine.
How do I set up my portable?
To set up a portable air conditioner is simple. Having unboxed the unit you attach the flexible hot air hose outlet to the back of the unit and place the other end out of the room you are cooling. This is typically through a window or door. Then simply plug the machine into a normal 13A socket, switch on and that's it!
Do I have to have a hose?
All refrigerant portables have to have a hose in order that the heat can escape. Do not confuse heat with humidity - with tumble driers you can place their hose into a condensing box but this is to remove moisture not heat. For an air conditioner you have to get the heat out of the room or it cannot cool it! The hose is typically 100-130mm in diameter (4-5"!) and is extendible from about 0.5 metre to 1.5-2.5 metre depending on the machine.
Where can I put the open end of the hose?
The flexible hose has to be routed so the open end exits the room you are cooling. The obvious solution is to open a window and put the hose out through the window. Most machines are supplied complete with an adaptor kit that reduces the amount the window has to be opened to only about 60mm. Alternatively the hose can be routed out through an open door, through a wall or even up into the ceiling providing the ceiling space is well ventilated, and the unit has a tank for condensate collection
Are portables good dehumidifiers?
All refrigerant air conditioners will remove moisture from the air as they cool it i.e. dehumidifies. This is an unavoidable effect of passing air over a cold surface to cool it (like the condensation that forms on a milk bottle when you take it out of the fridge). Whilst portable air conditioners are optimised for cooling performance they will dehumidify quite well. However, a portable air conditioner will only dehumidify within it's operating temperature range of typically 18-35C. Below this temperature the compressor does not start and the machine will not operate. A dedicated dehumidifier will be more efficient in operation (i.e. use less energy!) and can be made to work at temperatures right down to freezing point.
What happens to the water that the machine collects?
The water that collects in the portable air conditioner as it cools is dealt with in one of three ways. The machine may have a tank built in to collect the water with a float switch to turn the machine off when the tank is full. The tank is then simply removed, the water tipped away and the tank replaced. Alternatively a machine may have a condensate pump built in. These machines pump the water away continuously via a thin secondary pipe. This pipe can be placed to run outside with the main hot air hose or can be routed up and into a sink or container. Finally more sophisticated machines are re-evaporating the condensate into the warm air being exhausted via the flexible hose. These machines are generally capable of continuous use.
What maintenance is required?
Generally very little. The machines have a coarse air filter on the back which periodically needs a clean but other than that no regular maintenance is needed.
How long do they last?
Difficult one! Expect about 5-7 years life from these machines, when operating in a normal environment. Failures are eventually from either a leak of refrigerent or from failure of a fan motor or compressor.
