It can be tempting as a homeowner to buy a larger-than-necessary air conditioner with the hope that your home will cool off more quickly. However, purchase of an oversized air conditioner is one of the factors that can contribute to water intrusion in the home. Knowing why purchasing an oversized air conditioner can be a problem can help you avoid a costly mistake.
How can an oversized air conditioner contribute to water intrusion in your home?
Air conditioners are designed to do two jobs at once: cool the air, and dehumidify. This dehumidification is important, especially in homes with very energy efficient outer envelopes. Oversized air conditioners don't dehumidify well at all, leaving your home to absorb all the extra moisture. If your air conditioner is the proper size, it will dehumidify the air in your home, leaving much less water trapped within the walls of your house.
Why won't an oversized air conditioner dehumidify your home?
Air conditioners work by passing warm, moist air from the home over the very cold evaporator coil in the air conditioner. When this happens, the air temperature is supposed to drop, and the moisture in the air is supposed to collect on the coil (like dew). When enough moisture accumulates on the coil, it forms a large bead of water that drops into the condensate pan below. The pan fills with water, then exits the house at the drainage point.
Oversized air conditioners cool and send the air back into the house so quickly that the air conditioner doesn't have to run very long at all. As a result, moisture fails to collect on the coil, or if it does collect on the coil, it doesn't collect enough water to drop into the condensate pan. Moist, cool air is sent back into the home without being properly dehumidified.
What can happen if your home doesn't get dehumidified in summer?
If your home isn't properly dehumidified, you can experience mold problems. Over time, this can exacerbate allergies among members of your household and lead to health problems. In addition, if you have hardwood floors, your floorboards can absorb the moisture and become warped.
How can you ensure that you get an air conditioner that's properly sized for your home?
Have a qualified, certified air conditioner installation technician pick your air conditioner unit when it's time to buy another A/C. He or she will know how to properly size the air conditioner for your home.