When it comes to air-conditioner size, the common notion would be that ‘bigger is better.’ We all know the risks of installing an A/C that is too small such as the unit cycling more frequently to try and meet temperature demands all the while driving up utility bills and shortening the life span of the blower, compressor, fan and other components. What some residential and commercial consumers alike might not be aware of is that an air-conditioner that is too large is harmful as well.
You very much need to take a Goldilocks approach to finding an air-conditioner that is ‘just right.’ An oversized unit will cool the home or business quickly, thus turn off before it can truly ‘condition’ the air. Remember that an A/C is used not only to cool a room, but also to remove moisture and to dehumidify a space. When your air-conditioner is too large, moisture will remain in the room causing it to be very uncomfortable and prone to mold growth.
Finding the Right Size A/C
So the threats of an improperly sized air-conditioner range from paying exorbitantly high utility bills or sitting in a moisture-rich space with mold all over the walls. Now that you understand the importance of finding the perfectly sized A/C, how do you go about measuring for it and shopping for it?
Luckily, there aren’t hundreds of options when it comes to air-conditioner size. The units are sold based on their tonnage, ranging from 1 ton to 5 ton for residential uses and up to 16 tons for commercial buildings. It should be noted that the tonnage isn’t the weight of the A/C, but rather a measurement of the amount of heat that can be removed from the home or business in an hour.
Air-Conditioners and BTU
Really only the three things you need to understand when it comes to finding the right air-conditioner size is tons, BTU and square footage of your home or business. One British Thermal Unit (BTU) is equivalent to the amount of heat that would be produced if you burned a single match all the way through. 12,000 of these BTUs can be removed by one ton of air-conditioner capacity in an hour (1 ton = 12,000 BTUs) so a 3 ton unit could remove 36,000 BTUs and so on.
But how many BTUs exist in your space? There is an all-purpose equation to figure this out:
**(square footage of your home or business times 25, divided by 12,000) – 0.5 = recommended A/C tonnage**
So a 2,000 square foot home multiplied by 25 would give you 50,000. Divide 50,000 by 12,000 to get 4.16. Subtract the 0.5 and the recommendations would be 3.5 to 4 ton of air-conditioning capacity. You could get to that with a single 4 ton unit or a dual 2 ton unit. This is something commercial A/C prospects have to evaluate – how they get to the 10+ tons of air-conditioning capacity that is needed for larger spaces. Do they use single units, zoned systems, split-duct air-conditioners, etc.?
Finding Specific Air-Conditioner Size
The equation for finding the correct A/C size is very generic however. Does a home in Maine need the same air-conditioning capacity as a home in Arizona? You still need to figure out the square footage that needs cooled but the accepted climate zones are as follows:
These will give you a better rough estimate for the air-conditioning capacity needed based on your climate. With the help of an air-conditioner contractor however you can go even more in-depth. Using calculations such as number of windows in your home, ceiling height, typical number of occupants, your ideal temperature and humidity settings, etc. we can find the air-conditioner that is truly your exact Goldilocks.
Contact us today for more information about calculating the exact specs for your new A/C unit. We can also inspect your existing unit to see if it is properly sized or if it is the root cause of high utility bills or a humid and uncomfortable space.