Read reviewsUpdated: October 20, 2025
In the middle of a hot and humid summer, it’s tempting to answer this question with a big fat “NO” regardless of the size of your A/C. While you do need one big enough to cool your home, bigger is not necessarily better when you’re talking about air conditioners.
If you have one that is too big, it can waste a lot of energy and cause humidity problems in your home; however, one that’s too small can make everyone inside miserable during those hot summer months.
So, how do you know if your A/C is big enough? Here are some steps to calculate the right size for your home:
-
- Measure the space: Whether you want to cool just one or two rooms or a whole house, you’ll need to figure out how many square feet the area is. First, measure the length and width of the room or rooms to be cooled.
Most of time, you can find the square footage of your entire home in your mortgage paperwork or property tax statements, which will save you from having to re-calculate. If you do need to get out the tape measure, remember not to include your basement, attic space, or closets.
- Measure the space: Whether you want to cool just one or two rooms or a whole house, you’ll need to figure out how many square feet the area is. First, measure the length and width of the room or rooms to be cooled.
-
- Calculate the square feet: Once you have the length and the width of the area, you’ll need to multiply those two numbers together to come up with the square footage.
- Determine the cooling capacity: How fast an A/C can produce cool air is measured in BTUs (British Thermal Units) per hour. You need approximately 30-35 BTUs/hour for each square foot of space if you live in a warm climate and 50-60 if you live in a cooler climate.
Even though this is a good place to start, there are other factors that go in to determine what capacity unit your home needs. For example, the quality of insulation it has and how many people are living in it can affect the load size needed, as well.
At Richmond’s Air, we want to make sure you have the right system to keep you cool during these hot Texas summers. If you live in the Houston, Katy, or Spring areas, contact one of our experience HVAC technicians to discuss our services and your cooling needs.
