Air Conditioner Frequently Asked Questions

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Q - Which size air conditioner is best for me?

A - Before you choose an air conditioning unit you will need to work out which unit is most appropriate for you. There are several factors to be taken into account, most notably size of the room, but also location (eg office, bedroom, conservatory, etc), noise generated by the unit and energy efficiency.

As a very broad guide, the following can be used for the air conditioner which is appropriate for the size of your room (this does not apply to conservatories):

 Room Size (m²)

Recommended Air Conditioner


8,000 - 10,000 BTU


12,000 BTU


15,000 BTU

Q - How do I get started with my air conditioner?

A - The unit may have been stored on its side in transit or not the right way up so after unpacking the air conditioner, place the unit the right way up for at least three hours prior to turning on the power, to allow all refrigerant to move back to its proper position. Please follow the instructions carefully and set the unit up with the exhaust hose in the correct position you choose.

Q -  When should I start the air conditioner?

A -  When the sun rises it immediately starts heating up the brickwork in your building. Therefore you should start the air conditioner approximately 2 hours before the sun begins to shine into the room. This begins to remove the heat from the brickwork so that when the sun begins to shine into the room the unit is not struggling to remove heat from both the sun and from the brickwork.

Q -  What is the right way to use my air conditioner?

A -  Where possible try to close all windows and doors. Ideally, the exhaust hose should be vented through a hole in the wall, but if this is not possible, direct the exhaust hose away from the open window as far as possible without extending the hose. If you are directing the exhaust air hose through a window, try to fill the gaps in the open window as much as possible to ensure the warm air exiting through the exhaust hose is directed back in the room through the open window.

Q -  Is it possible to extend the exhaust hose on your air conditioner?

A -  In the vast majority of instances the answer is no. There are one or two portable air conditioners which have extendable exhaust hoses, but generally they cannot be extended. If you extend the hose, then this can cause a backlog of hot air in the exhaust hose and this can be emitted through the front of the unit which will mix with the cool air the unit is generating and make it emit warm air. It could also reduce the life of the unit.

Q -  Do air conditioners collect water?

A -  Water is collected in air conditioners as they also act as dehumidifiers. Some units collect water in a tray or container which must be emptied on a regular basis.
Other units collect surplus water which is then removed via a hose with the hot air. These units sometimes also have a small internal container that should be emptied occasionally. All air conditioners need to be emptied before they are put into storage, eg at the end of summer.

Q -  How do I care for my air conditioner?

A -  When it comes to maintenance, air conditioners should be considered in similar terms to a boiler or gas heater, and should be serviced regularly. A well used unit should be serviced annually, but a rarely used unit can be serviced less often. A service will include keeping the filters clean and ensuring there are no blockages of any sort which could affect the efficiency of the unit. Regular servicing will ensure your unit is less likely to break down when you need it most, makes it more efficient and reduces the energy cost of running the unit, while increasing its life.

Q -  Can our company get tax relief on air conditioners?

A -  Yes, some air conditioners are very efficient and therefore there is up to 100% Tax relief is available in the first year through the government’s Enhanced Capital Allowances. Please click here for information.

Q -  What are Inverter air conditioners?

A -  The inverter technology is integrated in the outdoor unit. This gives it speed control linked to output requirements. Using an inverter also allows the compressor to "soft start" which eliminates start up surge and allows it to run at slower speeds instead of stopping and starting. An inverter unit will gradually increase its capacity based on the capacity needed in the room to cool down or heat up the room. The non-inverter can be compared with switching on or off a light. Switching on this type of unit will start to run on full load. Inverters increase the life expectancy of the air conditioners and are around 30 % more efficient than conventional equipment.

Tips for getting the most out of your air conditioner.

Keep a room cool and use less energy by doing the following when using a room air conditioner:

  • Turn off any incandescent lights that are not needed, since these generate heat. Also, turn off any electrical equipment that is not being used.
  • Make sure outside doors and windows are closed to keep the cool air inside the house when using a refrigerate air conditioner; (evaporative air conditioners require some air flow).
  • Select the highest thermostat setting which is comfortable. Therefore the unit will not have to work too hard to achieve a lower temperature which may be too low for you.
  • If the room will be unoccupied for more than 12 hours, the air conditioner should be switched off.
  • Do not block the air conditioner vent.
  • Use the continuous air conditioner fan operation only when the resulting air movement is required to maintain comfortable conditions in the room.
  • The temperature of a heated room in winter should be between 18-21°C while the temperature of a cooled room in summer should be about 23-26°C (remember the humidity indoors will be low, so it will feel cooler).
  • If the machine has adjustable louvres, adjust them towards the ceiling when cooling, and towards the floor when heating (as cool air falls, hot air rises).