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Finding the right A/C unit for your home

A correctly-sized room air conditioning unit can make a big difference in its performance. A bigger unit does not guarantee better cooling. You need to make sure the air conditioner size is proportionate to the room.

It’s easy to think a larger unit produces more cool air, but not exactly. Air conditioners work by removing heat and humidity. While a larger unit will remove heat and cool off the room, it does so before getting rid of the humidity. This why some spaces feel cool, but also moist or clammy.

Here’s how to figure out the best size:

  • Measure the room’s square footage. Measure in feet, converting inches to fractions of a foot (i.e. 3 inches=.25 feet). Use the following formulas for different types of room shapes:

-square/rectangular rooms: length times width

-triangular rooms: length times width, divided by two

-other rooms: mark off the room’s space into squares/rectangles/triangles and use the above formulas

  • Pick the correct cooling capacity. Once you know the room’s square footage, select the corresponding capacity.
  • Make any necessary adjustments. Other factors can contribute to what size is best for you. If the room has more shade, choose a 10 percent lower capacity. Vice versa, if a room is more exposed to sunlight, pick a 10 percent higher capacity. If more than two people will be occupying the room, add on 600 BTUs (British thermal units) per person. If you’re placing the A/C unit in a kitchen, capacity needs to be increased by 4,000 BTUs.

Where you place the unit makes a difference too. Make sure wherever you choose to mount it allows the air to flow in the right direction without any restraints. The right size and placement of your A/C unit will produce the most comfort, and increase energy efficiency.