What Size Air Conditioner Do I Need For 1500 Square Feet?

Choosing the right size air conditioner is imperative to keeping your home cool. If the air conditioner is too small, it won’t be able to cool the space adequately. On the other hand, too large of an air conditioner can make you feel like a popsicle and waste money.

What size air conditioner do I need for 1500 square feet? A 1500 square foot home needs a 2.5 ton AC unit. A 2.5 ton AC unit will adequately cool the home without making it feel too frigid or wasting any money.

House Square Footage BTUs Needed
100 – 150 5,000
150 – 250 6,000
250 – 300 7,000
300 – 350 8,000
350 – 400 9,000
400 – 450 10,000
450 – 500 12,000
500 – 700 14,000
700 – 1,000 18,000
1,000 – 1,200 21,000
1,200 – 1,400 23,000
1,400 – 1,500 24,000
1,500 – 2,000 30,000
2,000 – 2,500 34,000

To find out more about selecting the right size air conditioner for your home, keep reading. This article covers everything relating to air conditioner sizings, such as load calculation, BTUs, the importance of choosing the right size, and more.

Load Calculation

Load calculation is how HVAC professionals find the right size air conditioner for your home. Initially, HVAC companies guessed what size unit a home needed based on the square footage alone. Often, simply using square footage leads to installing too large of an AC unit.

Today, however, multiple factors affect the load calculation. With the help of computers and fancy software, HVAC professionals can easily determine which AC unit to install in your home based on several different factors.

These factors help to determine heat and airflow in your home. For example, your home’s construction materials can either inhibit airflow or encourage it. So, your HVAC system needs to be strong enough to keep the airflow in check.

Though there are different types of load calculations, the most common is called the block load. The block load only tells you how large or small of a unit you need for your home. In other words, it looks at the home as a whole, allowing a total load estimation.

Factors Affecting Load Calculation

Here are some of the most critical factors that affect a loading calculation:

Your home’s construction materials

As we mentioned above, construction materials affect load calculation a lot. Certain materials do a better job at insulating the home. As a result, the unit may not need to be as large since the home itself can trap in the cool air and block out the heat.

The number of windows

Windows do a terrible job of insulating your home. The more windows you have, the less insulation your home offers. For this reason, homes with more windows need a much stronger unit since the home itself does not offer much insulation. If your home only has a few windows, the unit will not need to be as powerful.

The size of the rooms

Individual room size impacts load calculation as well. Smaller rooms do not require as much power to cool or heat. This is simply because there is less space and air within the room. In contrast, homes with large rooms will need a more powerful unit. Larger rooms require a bit more effort to completely cool or heat.

Your home’s insulation levels

Insulation levels are critical when estimating calculations. During the summer months, insulation traps the cool air inside the home and keeps the hot air out. On the flip side, insulation traps in the heat during the winter. 

If your home has a lot of insulation, you can use a smaller unit. However, houses with less insulation will need a much larger unit to offset the outside temperatures.

BTU to Tons Calculation

Whenever you start looking at HVAC systems, you will often see the term BTU. BTU stands for British Thermal Units. This reading measures the amount of energy required to increase 1 pound of water’s temperature by 1 degree Fahrenheit.

Sometimes, you will need to convert BTU to tons. Luckily, this calculation is straightforward. 1 ton is equal to 12,000 BTUs. Say you have 3 tons. That will equal 36,000 BTUs. If you don’t want to do the math yourself, you can use the tonnage to BTUs chart below.  

Tons to BTU Table

Tonnage BTU
1 ton 12,000 BTU
1.5 ton 18,000 BTU
2 ton 24,000 BTU
2.5 ton 30,000 BTU
3 ton 36,000 BTU
4 ton 48,000 BTU
5 ton 60,000 BTU
6 ton 72,000 BTU
7 ton 84,000 BTU
8 ton 96,000 BTU

Tons to Square Feet Calculation

You may also need to convert tons to square feet or vice versa. The calculation for this conversion is a bit more difficult than converting tons to BTU. In general, you will need 1 ton for every 600 square feet. The easiest way to get this calculation is to use a ton to square foot table, which you can find below.

Tons to Square Foot Table

Area in Square Feet Tonnage
600 sq. ft. 1 ton
900 sq. ft. 1.5 ton
1,200 sq. ft. 2 ton
1,500 sq. ft. 2.5 ton
1,800 sq. ft. 3 ton
2,100 sq. ft. 3.5 ton
2,400 sq. ft. 4 ton
2,700 sq. ft. 4.5 ton
3,000 sq. ft. 5 ton
3,300 sq. ft. 5.5 ton
3,600 sq. ft. 6 ton

Importance of Choosing the Right Size Unit

At first glance, you might be confused why choosing the right size unit is important. Choosing the right size unit is important for saving money and cooling your home effectively. Believe it or not, both getting too large or too small of a unit leads to costly and uncomfortable consequences.

For example, too large of an AC unit lead to short cycling, resulting in unideal moisture content in the air. It will also increase the energy use within your home, upping your utility cost in the process. On the flip side, too small of a unit lead to high electricity bills, fast wear out, and increased breakdowns due to overwork.

AC Systems To Efficiently Cool 1500 Square Feet

You can use two main AC systems to efficiently cool a 1500 square foot area: a central AC unit and mini-split systems.

Central AC

A central AC unit is one system that connects to the rooms via ductwork.


  • Consistent temperature year-round
  • Filtered air
  • Heating and air combo possibility


  • Higher energy bill
  • Required duct maintenance

Mini-Split Systems

Mini-split systems are installed in individual rooms, allowing more flexibility and control by the room.


  • Flexible
  • Easy to install
  • No duct maintenance


  • Higher cost
  • Unattractive

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