4.7 / 5 Ratings
Based on 281 Reviews

Customer Reviews

800 Jesse Jewell Pkwy.
Suite B

Monday - Friday
7:30am - 5pm
Emergency Service Available

Request Service

Schedule Now

Professional Services


Schedule HVAC Services Today

Professional HVAC & Cooling Since 1988 | 470-228-6848!



What Size Air Conditioner Do I Need?

When you are shopping for a new air conditioner for your house, it’s important to choose the right size in order to save money and reduce energy use.

In this article, we will explain how to choose a correctly sized air conditioner.

Understanding British Thermal Units

The British Thermal Unit (BTU) is a metric used to measure the amount of heat that an AC unit can remove from a room within one hour. If you look at air conditioning units, you’ll notice that they are rated by BTUs. A higher BTU means more cooling power. For example, a 1-ton air conditioning unit has the capacity to cool up to 12,000 BTUs per hour while a 4-ton AC can remove 48, 000 BTUs of heat per hour from the house.

The size of your house will determine the right BTU rating to choose. Below are some recommendations:

  • 1000 square feet needs 20,000 BTUs/hr
  • 1800 square feet needs 36, 000 BTUs/hr
  • 2100 square feet needs 42,000 BTUs/hr
  • 3000 square feet needs 60, 000 BTUs/hr

As recommended by the U.S. Department of Energy, air conditioners need 20 BTUs per square foot.

This is expressed with a simple formula for calculating the required BTUs.

20 BTUs x 1 square footage

That’s to say, if you want to cool a 2000 sq. ft. house with an average ceiling height, you will need a 40,000 BTU air conditioner. However, you’ll need to consider additional factors such as the local climate, sun exposure, and the number and size of the windows.

If your house is heavily shaded, you’ll need to subtract 10% of the recommended capacity. For example, if the recommended BTU rating for a 2000 sq. ft. house is 40,000 BTUs, you’ll need to subtract about 4,000 BTUs if your house is heavily shaded. Conversely, if your house gets a lot of sunlight, increase your AC unit’s cooling power by 10%.

The U.S. Department of Energy also recommends that you increase the capacity by 600 if your house is occupied by more than two people at a time.

If your AC unit is too small for your house, it may have to run at maximum output more often, and this can lead to low airflow, increased wear and tear, and increased energy usage. On the other hand, an oversized AC unit can lead to a number of problems, including higher energy bills, uneven temperatures, inefficient operation, and high humidity.

It’s advisable to consult with a trusted HVAC company when you are unable to choose the right size air conditioner for your house.

Need AC Installation or AC Repair? Call Absolute HVAC Service

Is it time to install a modern and energy-efficient air conditioner in your home or office? Is your air conditioner in disrepair and you are looking for a professional HVAC company to help you with AC repair? Absolute HVAC Service is here to help. We are a trusted HVAC company specializing in HVAC installation, HVAC repair, furnace replacement, indoor air quality testing, and many other services. Our AC installation team can help you choose the right air conditioner for your house.