Servicing your air conditioning

The recommendation for servicing an air conditioning unit is at least once per year, ideally before the cooling season begins in summer. This should only be done by qualified air conditioning service personnel. Often, a service agreement can be arranged with the contractor, who installed the unit or a reputable air conditioning maintenance company. Most warranties require that the air conditioner be serviced on a regular schedule for the warranty to be valid. Improper maintenance usually voids the warranty. Always refer to the maintenance manual for specific maintenance and warranty terms and conditions.

Maintaining air filters and drains

The most important maintenance task that will ensure the efficiency of your air conditioner is to routinely replace or clean its filters. Clogged and/or dirty filters block normal airflow and reduce a system's efficiency significantly. With normal airflow obstructed, the air that bypasses the filter may carry dirt directly into the evaporator coil and impair the coil's heat-absorbing capacity. Replacing a dirty, clogged filter with a clean one can lower your air conditioner's energy consumption by 5% to 15%.

For central air conditioners, filters are generally located somewhere along the return duct's length. Common filter location is the ceilings or in the air handling unit itself and it is recommended they be cleaned or replaced by a qualified air conditioning service provider.  Room air conditioners have a filter mounted in the grill that faces into the room.


Some types of filter are reusable; others must be replaced. They are available in a variety of types and efficiencies. Clean or replace your air conditioning system's filter or filters every month or two during the cooling season. Filters may need more frequent attention if the air conditioner is in constant use, is subjected to dusty conditions, or you have pets in the house.

Clogged drain lines in an air handling unit will cause water damage in your house and prevent the unit from reducing humidity, and the resulting excess moisture may discolour walls or carpet, so please ask your service provider to clean and flush the drain lines regularly as well.

Setting the air conditioner thermostat

Adjust the setpoint temperature up a few degrees – instead of cooling your home to 22°C, try 24°C or 25°C. For every degree you lower your thermostat, you can save approximately 3% on electricity costs. Generally, lowering your thermostat by five degrees will make a significant impact on the energy bill.

If you go away during the summer, do not switch your air conditioner off. If there is an option to put it on ‘auto’ setting, please do so. It will intermittently switch the fan off if the temperature has been reached. This will protect your home from adverse effects of humidity and excessive heat while circulating the air at a slightly higher temperature. It will also reduce electricity consumption.

On a hot day

On a hot day, you should:

  • Keep outside doors and windows closed
  • Keep doors to non-air-conditioned areas (e.g. laundries, bathrooms etc.) closed
  • Note that any doorways on the return air path will need to be kept open, which may mean that doors to an unconditioned hallway will need to be kept open
  • Keep windows, which are exposed to the sun, shaded by using internal blinds or curtains
  • Operate the fan on high speed; but on humid days, a low fan speed may be more comfortable