Bigger Isn't Always Better When It Comes To Your Air Conditioning Unit

As the summer comes to an end, you may have found your air conditioner dos not cool your home as well as you would like. Depending on the age and the cost to repair an old system, you may be thinking of replacing it.

What size unit is right for your home?

Most people think that the bigger the unit the better. But if you buy an air conditioner that is too large, thinking it will provide better cooling you may be wasting your money. Over sized equipment is actually less effective and less efficient.

Your air conditioner does two jobs when it runs. It removes both heat and humidity from the air. If the unit is too large, it will cool the room quickly, but only remove some of the humidity. This leaves the room with a damp, clammy feeling. A properly sized unit will remove humidity effectively as it cools.

As the air passes over the evaporator coil which is very cold, the temperature drops about 20 degrees. In Illinois where we have high relative humidity levels, the evaporator coil doesn't just cool the air but also acts as a dehumidifier. This happens when the air hits the coil and the temperature of the coil is below the dew point of the air.

Buying the biggest air cooling system doesn't mean you are going to be happy. Get a unit that is too big for your home and water vapour will condense on the coils but you won't get enough condensation on the coil for the water to start dripping down into the pan below the coil. If this happens the water isn't drained to the outside. Instead it can go back into the air in your home resulting in the that tropical jungle feeling.

An over sized unit can also be more expensive to buy and to operate. A unit that is too large will start and stop more often. This shortens the life span of the equipment. When a cooling system is over sized, it starts up and shuts down a lot more because it runs for only a short time to meet the thermostat set point. All those starts and stops mean you'll probably be repairing it more often and replacing it sooner.

Buying the correct size unit for your home will not only save you money on the equipment but also on the energy costs and on repairs.