Choosing the Right Size Air Conditioner

If you’re in the market for a new air conditioner and live in the Seattle area, selecting the right sized unit for your space is essential. When an HVAC unit’s cooling capacity is too small, it will fail to keep your home at a comfortable temperature. When your A/C is too big for your home, it will use more electricity than is necessary and will make your home’s interior unpleasantly humid. Figuring out the right size air conditioner for your needs is vital for maximizing the unit’s efficiency and performance.

Measure your home’s square footage.

Choose right size of AC Determining the size air conditioner that you need will require some measurements and a bit of math. First, measure the square footage of each of the rooms that you intend to cool. Use a tape measure to learn the length and width of one room, and write these measurements down. Next, multiply these two numbers to figure out the square footage. Complete this process for each room of the house, writing down the measurements and totals as you work. Be sure to include only areas that your central ducts reach, excluding basements, garages, and attics.

Determine your cooling capacity needs.

The next step toward finding out what size air conditioner you need is to use your measurements to determine the cooling capacity required for your home. The cooling capacity of central air systems and room air conditioners is measured using British Thermal Units (BTUs) per hour. The United States Department of Energy’s Energy Star website provides guidelines for determining the BTUs needed for your home or room’s square footage .

Consider your home’s additional factors.

Choosing the right size air conditioner can depend on a few things besides your home’s square footage. If your house receives significant sunlight or has many windows, it may need more cooling capacity than one that is shaded or allows less sunlight into the interior. Your home’s insulation will also contribute to its need for cooling capacity. Experts recommend having multiple HVAC contractors perform an estimate on your home before you make a decision about purchasing your new air conditioner.