size ac

When it’s time to install a new air conditioning system in your home, it’s important to know exactly what size you need. Air conditioner capacity varies greatly, and is designed to serve the needs of a specifically sized space. At Hometown Comfort, we are here to help you discover the air conditioner size that will best meet your needs.    


Why is finding the right size AC unit so important?

An air conditioner that is too large for your home will start quickly, cool quickly, and shut down before running through the entire cycle. The problem with this is that the heat will return quickly, and cause your system engage into another cooling cycle far sooner than the right sized unit would, causing a higher energy bill. A system that is too small will run constantly, trying in vain to catch up to your set temperature. Your house may feel sufficiently cooled, but again, a constantly running system will result in an unruly electric bill.


Tons & BTUs

AC systems come in a range of sizes, and their size is measured in “tons.” A “ton” is a measure of an air conditioner’s ability to cool. A BTU (British thermal unit), is the amount of energy needed to heat or cool one pound of water by one degree Fahrenheit. That means 1-ton air conditioner can cool 12,000 pounds of water by one degree every hour, and a “2-ton” central air conditioner is able to cool 24,000 BTUs per hour.


Find the square footage

The first determinant in air conditioner sizing is the square footage of the area to be cooled. The easiest way to discover this number is to find your home’s floor plan. As an alternative, you could measure the area of each room (length x width = area). The total square footage of the space to be cooled makes up the basis for the air conditioner size you will need.


A basic formula

There is a basic, old-school formula for calculating AC size which basically divides square footage by the water cooling (per hour) standard for a ton,12,000 pounds. It is not recommended to follow this formula without weighing other factors in something called a “room by room load calculation”.


Formula for finding AC Size: ((HOUSE SQ. FOOTAGE X 25 / 12,000) – .5) = required tons.


Example: a 1,500 square foot home =

    • 1,500 X 25 = 37,500
    • 37,500 / 12,000 = 3.1
    • 3.1 – 0.5 = 2.6

  • 2.5 or a 3-ton sized AC unit for a 1,500 sq. foot home


Room by room

The room by room factoring is best conducted by a professional HVAC specialist. This is a basic variation on that in-depth report. You see, each room has its own set of conditions to be considered in your overall cooling plan. The individual characteristics of the rooms often affects the BTU capacity and AC unit size necessary for a successful cooling strategy. Some factors to consider:

  • Sunny rooms  – require more energy for cooling
  • Heavily shaded rooms – require less energy for cooling
  • Non-insulated rooms – require more energy to sustain cooling (as cooled air is lost quickly)
  • Kitchens – require more energy for cooling due to heat gain from electronics & appliances
  • Rooms used by two or more people – require more energy for cooling to offset body heat

For more help determining the air conditioner size that will best meet your needs, contact Hometown Comfort today. Our expert technicians can guide you a thorough assessment of your unique needs, and honest, reliable advice. AtHometown Comfort Heating & Cooling, it is our pleasure to help you make the best decision for your home and your budget. We can help you upgrade to a newhigh SEER system is best for maximum function and cost effectiveness. Contact our friendly, helpful team at Hometown Comfort today at (615) 240-7056.

Hometown Comfort Heating & Cooling: Your hometown solution for dependable comfort!

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