Over the years we’ve been asked a lot about what makes a good central air conditioning system. While we don’t recommend any specific brand, here are some buying tips for central air conditioning units.
Choose A Quiet Unit — Yes, there are units that are quieter than others. Look for units with two speed fans at the outdoor condenser unit. The larger the diameter of the fan the more likely the unit will be quieter as it will need less RPM’s to expel the heat. An insulated, separate, compressor compartment will help too. Ontario has set 7.6 BELS (a sound rating) as the standard. A rating of 7.2 or lower is very good. Where the unit is installed outside will also make a difference.
Good Design Critical — Look for a factory sealed refrigerant system installed with pre-charged lines and quick disconnect fittings. Ensure the unit has a low ambient cut out switch that turns the unit off when outdoor temperatures fall below about 15 C. Vinyl coated grills, polyester paint, and, corrosion resistant screws on the condenser unit will make the unit remain attractive for years. Low Operating Costs — Seasonal Energy Efficiency Ratio (SEER) is a measurement of the cooling efficiency. A SEER value of 9 is the minimum performance standard in Ontario. Some manufacturers have equipment with ratings of 11 or higher. Choosing a unit with a SEER rating of 11, compared to 10, is an increase in efficiency of 10% and 10% reduction in operating costs. Choose a SEER rating as high as practical within your budget.
Ease of Service — Look for copper tubing with aluminium fins as opposed to all aluminium. Access to the compressor is also important.
Environmentally Friendly — Choose a unit whose refrigerant is has the least effect on the environment and in particular the ozone layer.
What Size Unit Is Required? — The term “ton” is used to describe the amount of ice required to cool an area. (1 ton = 12,000 BTU/HR). A general rule of thumb, based on house size, is:
Sq. Ft. Tons Required
1,000 – 1,500 1.5
1,500 – 2,000 2.0
2,000 – 2,500 2.5
2,500 – 3,000 3.0
Clearly, this will vary from house to house based on, but not limited to, the amount of insulation, windows, skylights, shade trees, etc.