What Size Air Conditioner Do I Need for My Home?

AC System in Spring, Texas

AC size is important whether you are replacing your air conditioner, installing one in a new construction project, or just investigating. How are systems measured, why is size so important, and how do you choose the right one for your home? North Point Air Conditioning & Heating in Spring has put together this information to help you have confidence when choosing the best size for your home’s AC unit.

Is Size Really That Important?

Air conditioner size is incredibly important for your system to run properly without wasting money or energy. When your AC is too small for your space, it runs much longer than it should, driving up your utility bill and causing unnecessary wear and tear on your unit.

When your AC is too big, it will not run long enough to dehumidify the space. It will also run these shorter cycles more often trying to keep your space at the right temperature. This not only drives up your utility cost but also puts unnecessary strain on your system, leading to premature failures.

How Is AC Size Measured?

Air conditioning sizes are not measured in inches or feet but in British thermal units, or BTUs. One BTU is the amount of energy it takes to warm 1 pound of water by 1 degree Fahrenheit.

You will see the size of an air conditioner rated in thousands of BTUs. This indicates how much the system can cool the air per hour. It makes sense to think that more BTUs would be better to achieve more cooling more quickly, but this isn’t always correct.

Larger-capacity systems have a minimum amount of energy they use, even if the unit does not run as long. As already discussed, it will not achieve the same level of comfort due to not dehumidifying as well. This means you end up paying more to run the system but not being as comfortable as you should be when it is running.

Calculate Your Space

The first thing you need to do to determine what size air conditioner you need is to calculate your space. You may want to use the following to double-check even if you already have the square footage.

Go through your home and first note all the levels that are serviced by your HVAC system. Be sure to look at your attic, garage, and basement to see if there is ductwork with vents. If so, include those spaces as well.

Next, go room by room and measure the length and width of the room, then multiply these numbers. This gives you the square footage of each room, which you then add together. Do not forget the closets and hallways as you add these together to get the full sense of your space.

Figure BTUs

Next, you take the space your system cools and convert that to the BTUs needed to service it properly. There is no perfect formula that fits everyone’s situation, but there is a general rule of thumb you can use.

Take your square feet measurement and multiply it by 20, for 20 BTUs per square foot serviced. So, if your home is 1,800 square feet, your starting point will be 36,000 BTUs for your system.

As mentioned, this is just a starting point so you can start planning. There are many variables you should consider to get to the final size you will need.

Understanding the Variables

There are a number of variables you should consider before deciding on your final AC size. First, think about how many people typically occupy your home. This includes both the people living there and extra people who are commonly in your space.

The 20 BTUs per square foot accommodates two people. For every additional person you add to your home, you should add 600 additional BTUs. Be sure to consider if you frequently have large gatherings while trying to cool your home as well.

Next, consider the environment around your home and the effect it has on your AC. If your home is shaded most of the day, you can reduce your BTU capacity by about 10%. On the other hand, you will need to add 10% if it receives direct sunlight most of the day.

Getting Your New System

Before getting your system, you will want to consult with a couple of HVAC companies to check their recommendations. Ultimately, you should choose the company with whom you felt the most trust. Not only will this company be responsible for installing your system but also servicing any warranty claims.

People around Spring have turned to North Point Air Conditioning & Heating for new air conditioners since 1978. Our expert technicians also offer AC maintenance and repair, as well as heating installation, maintenance, and repair. Call to schedule your new air conditioner consultation today.

Posted in AC