It’s important for your home or workplace to have an air conditioning unit that is the proper size. As you probably know, a unit that is too small won’t be able to keep your home cool. It will constantly be running – trying and failing to cool things down and this wastes a lot of energy. It’s important to make sure that your unit isn’t too big either. Oversized units waste energy and cause a high energy bill. Modern a/c units are designed to run a full cycle to operate efficiently. They lower the degrees at a steady rate until reaching the desired temperature. An oversized unit will quickly cool the space and automatically shut off. When a system is unable to run a full cycle, it wastes a lot of energy. When the temperature begins to heat up again, the unit will turn on, lower the temperature, and turn off repeatedly. The most energy is used to start the air conditioner, so constantly turning on and off causes the unit to waste a lot of extra energy. So too big or too small wastes energy – look for a unit size that is “just right”. Reliance Home Comfort can help you pick out the correct size air conditioner for you and help you install your HVAC system.

Central air conditioners are measured by “tonnage”. A “ton” is the unit of measure used to rate an air conditioner’s cooling power. Small units start at 1.5 ton units and go up to 5 ton units – anything over 5 tons is considered commercial. Unit sizes increase by the half-size. Residential spaces almost never exceed 5 tons. Large homes that need more than 5 tons of cooling should have 2 smaller units installed. If your home rates 6 tons, two 3 ton units should be installed instead of one 6 ton unit. Having two smaller units can allow you to have heating and cooling zones – one for the upstairs, and one for the downstairs. If your home isn’t big enough to warrant two units, you can still talk to Reliance Home Comfort about zoned heating and cooling using other methods.

Now let’s look at how to calculate the size unit your home will need. There are different methods to do the calculations. Two methods will give you an estimated answer.

An equation → ((House square footage times 30, divided by 12,000) – 1.0) = Required Tonnage

For example, if you have a 1,900 square foot home, here is the math you would need to do:

  1. 1,900 x 30 = 57,000
  2. 57,000 / 12,000 = 4.75
  3. 4.75 – 1.0 = 3.75
  4. 3.75 would need to be rounded up to the next half size. If your home is 1,900 square feet, you would need a 4 ton a/c unit for efficient cooling. While this equation is for the average American home, if you live in an especially hot and dry area, like the southwest, skip step 3 and don’t subtract 1.0.

If you aren’t great at math, or want a more accurate calculation, contact us at Reliance Home Comfort. Our team can determine what would be best for your home, including a few recommendations in terms of good brands and models. We are here to help with any and all heating and cooling questions. You may be wondering “How big of an a/c unit do I need?”, or “How do I install an a/c unit?”, or maybe “Is it time to replace my current a/c unit?”, schedule an appointment with Reliance Home Comfort. We can assess how efficiently your air conditioning unit is working and give you a more specific plan to improve it. Don’t wait until the dog days of summer to look at your air conditioning, let Reliance Home Comfort give it a little TLC today.