Read the EnerGuide label for the EER (Energy Efficiency Ratio) rating. The higher the number, the more efficient the unit.

Also look for the ENERGY STAR® symbol on the EnerGuide label. ENERGY STAR room air conditioners have more than the Government of Canada's yearly minimum standard of energy efficiency by at least 10 per cent.

Maintenance for room air conditioners

• The filter behind the grill should be washed monthly. Unplug the unit. Remove the filter and wash it, allowing it to dry completely before reinstalling.
  
• In the spring and fall, clean all dirt from the coils. In the fall, unplug the unit, remove it from the window and store in a dry area after cleaning. Replace the storm window.

Central Air
Since central air is a major purchase, get a number of quotes from reputable dealers. The dealer can help you find a unit that is the right size for your home. Also be sure to compare the sound ratings of different units.

Compare the EnerGuide SEER (Seasonal Energy Efficiency Ratio) ratings. They range from 10 to 17. The higher the number, the more efficient the model.

Maintenance for central air conditioners

• Check filters monthly and replace or clean if necessary
  
• Have a professional inspect your unit annually
  
• Keep the outdoor unit free of leaves and grass and cover in winter

Power ventilation can be an effective alternative
As an alternative or an addition to air conditioning, think about power ventilation systems. There are two types of central units: exhaust-only systems and packaged ventilators.

In homes with an adequate air supply, exhaust-only systems and packaged ventilators are effective for reducing heat and humidity in the summer and providing ventilation year-round. However, in the winter, these systems will exhaust the warm air which will increase your heating costs.

A power ventilator in the attic is one of the most economical methods of reducing indoor summer temperatures. The initial cost is relatively low and so are the operating costs. However, the attic must be perfectly sealed for the unit to operate properly.

In some cases, power ventilation will be enough to provide you with a comfortable interior environment without having to add air conditioning. If you already have air conditioning, the addition of a power ventilator may reduce the amount of time the air conditioner runs.

Maintenance for power ventilation

• Regularly clean or replace both intake and exhaust filters
  
• For heat recovery ventilators, clean the heat exchanger core annually. If the unit has a condensation drain, clean the drain line to make sure it's open and free flowing. Clean the outside intake and exhaust vents of any debris
  
• Clean and vacuum vent grills in each room periodically