Text by Lori Broadfoot
Thankfully modern automotive air-cooling units have changed greatly since the blocks of ice once used under horse carriages to keep drivers cool in the hot summer sun. Nowadays, personal climate control is available at an arm’s-reach push of a button on your dashboard. It has been estimated about 80% of all cars on the road today have A/C units.
Most modern cooling units are now controlled by temperature-regulated, combined heating/cooling systems. These computerized systems will maintain a given temperature within your car’s interior, adjusting from cooling to heating automatically. Automatic Temperature Control (ATC) systems are more dependable and efficient, especially without the fuel-burning over-cooling or heating that usually results from manual temperature regulation.
With the complexity of the computer controls and electronics governing the new ATC systems, repairing a malfunctioning unit is beyond the scope of most home mechanics. But repairing an older model A/C unit is no longer a do-it-yourself project either. If you don’t know your Thermal Expansion Valve from your Accumulator, you should leave the repairs to the professionals, but it helps to be informed of your options, and their associated costs.
In the mid-eighties, many countries signed the Montreal Protocol, to limit the production of elements known to deplete earth’s ozone layer. How does this influence the cost of repairing your car’s air conditioning system? Freon is the registered trade name for the refrigerant R-12, manufactured by DuPont. Soon after its patent in 1928, Freon became the standard for all refrigerators, and eventually for automobile air-cooling units. Freon was believed to be a harmless gas; it is non-toxic, odourless and non-flammable. Only decades later did studies show this chlorofluorocarbon (CFC) refrigerant to be harmful to the earth’s ozone layer, and its manufacture has been banned in the U.S.
In order to repair and recharge a cooling system in an older vehicle, mechanics now have to adhere to strict environmental laws, facilitating the use of expensive equipment dedicated to retrieving these banned chemicals. Mechanics also have to receive certification, both to repair A/C units and to purchase the refrigerants used to fill them.
Retrofitting may be another option for an older system, in order to use the new environmentally friendly coolant, R-134a. This CFC-free refrigerant has a higher operating pressure, necessitating the retrofitting, which will add to the cost of repairing an A/C unit.
In the end, it may be more efficient, fuel-wise, to drive your car with the windows rolled down, but these savings may be negated when traveling at faster highway speeds.