Bigger is not always better when planning for a new central air installation for your home. Don’t make the mistake of buying more capacity than you need. A larger A/C will actually cost more to operate and make you less comfortable. Why? Because it will have short “on” and “off” periods, allowing too wide a humidity range. The short “on” periods of an oversized air conditioner will prevent it from removing enough humidity from your home which is an important part of its function. An air conditioner that’s too big will result in clamminess and mold formation.
A bigger air conditioner is more powerful but not better for your home. Here’s why… when an air conditioning system runs, it does two jobs. It lowers the temperature of the air, and it removes moisture from the air. In order to remove moisture from the air, the air conditioning system needs to run for a certain amount of time until this is accomplished. While the air conditioner is running and the blower motor is pushing air over the indoor coil, or the evaporator, the air temperature will drop. As a result, water vapor will condense on the evaporator coil.
This occurs in oversized air conditioners too. However, oversized air conditioners don’t run long enough to satisfy the humidity issue because they satisfy the temperature set on the thermostat quickly and then shut off. The short cycling of the air conditioner does not remove enough humidity in the home and adds wear and tear on the air conditioner. It may mean that you need a c service more frequently, adding to your overall operating expense. An air conditioning system that’s too large or too powerful for your home can waste money, energy and can contribute to your air conditioner icing up.
“Lots of things are better if they’re bigger, like TVs or ice cream cones, but not air conditioning systems,” says Rick Fravel, Contemporary Air Systems owner. “ An A/C unit is supposed to dehumidify the house as well as cool it. A unit that’s too large will turn on and off too quick, bringing the temperature down fast but not removing the humidity. So you’re losing comfort as well.” In your home if your air conditioner runs for only 5 to 10 minutes before shutting off, it’s oversized. If it runs over half an hour, it’s probably sized correctly. A properly sized unit will usually need service just once at the beginning of the cooling season, plus perhaps an extra filter change or two depending upon your use and household. Luckily this ac tune up is a service that is already included as part of our Home Comfort Club.
If you’re building a new home or adding an addition, Rick recommends performing a Manual J load calculation to determine the heating and cooling loads. In fact, some counties make the Manual J load calculation mandatory when applying for an HVAC permit. Having a qualified provider perform this service for you and following their recommendations will ensure your maximum lifetime savings and comfort for the system you choose.