thisplace.com.au - Air Conditioning

The size of the air conditioning unit you buy largely depends on the area you wish to air condition. And there's quite a choice. Before you decide on any air conditioning unit, it's worth getting expert advice.

First make sure you get the correct sized unit

When you talk to an air conditioning specialist, they'll have a better appreciation of the size and type of unit you need if you prepare the following checklist:

Sketch of the floor plan of each room to be air conditioned and/or heated.
Type of construction of the building.
Direction the room faces, ie. north, south, east or west.
Size and position of windows, large areas of glass exposed to the sun can substantially increase heat gains in summer and result in undesirable hat losses during cold weather.
Size and shape of doorways or other openings in the area to be air conditioned.
Do you have insulation in your ceiling or walls? Is so, what type and thickness.
Floor dimensions (length, width) and height to ceiling.
Intended use of the area, day and / or night use.
Number of people who normally occupy the space.

Rating of air conditioners

Air conditioners are rated by their cooling or heating capacities in watts or kilowatts (1000 watts). This, the rate of heat transfer, is not be confused with the energy input to the air conditioner.

Work out what size is needed

As an approximate guide the following can be used to work out what size air conditioner you would need.

Living room, an average living area 25m2 would require an air conditioner with a cooling and heating capacity around 3500 watts. As a rough guide to selecting an air conditioner in south east Queensland, calculations can be based on 140 watts per m2 of floor area.
Bedroom, a bedroom of 15m2 would require an air conditioner with a cooling/heating capacity around 1650 watts. For an air conditioning unit that is to be used only in bedrooms overnight, calculate on the basis of 110 watts per m2 of floor area.
Part home/adjoining areas, a vertical type unit provides genuine, open plan style air comfort control. A unit with a capacity of 5860 watts will cool approximately 40m2.

An oversized system, apart from costing you more to buy and run, may be less effective during the summer than one correctly sized for the area, particularly when the weather is humid. This is because an oversized unit will rapidly cool the area without allowing sufficient time for dehumidification (moisture removal).

Features

When selecting your air conditioner check for the following features:

powerful cooling system
quiet operation
positive automatic thermostat
multi speed fans
directional air control grille
ventilation
dehumidification
special easy to clean filters
reverse cycle operation ('Heat Pumps'). (Reverse cycle air conditioning is the most cost effective form of heating. It's a real energy miser. Up to three times more efficient than other electrical heaters and even better in comparison to kerosene, oil and gas appliances).

Star rating system

Domestic air conditioners with an output up to 7.5ks have energy labels that rate their energy efficiency on a scale of one to six. The labels also list the amount of energy used over 500 hours when tested to the Australian Standard. Reverse cycle units carry two ratings (for cooling and heating), marked in blue and red bands. Information for cooling only units can be found marked in blue. The most energy efficient appliances display the Galaxy Energy Award labels. Purchasing energy efficient appliances help you save energy and money on running costs. Be sure to compare models of similar features and size and consider the information printed on the label.

Source: Energex Energy Institute, A Guide to Better Air Conditioning