4 Ton vs 5 Ton Air Conditioner

Alexis Labadie Profile image

Written by:

Updated May 17, 2023

When you replace your air conditioning unit, you want to get the best quality and efficiency for your budget. Because of this, you might wonder whether you need a 4-ton vs 5-ton air conditioner. And, you might be considering top brands, including a Hisense air conditioner vs an LG air conditioner. Having all these different brands out there might make it a little difficult to choose an air conditioner that’s right for you.


  • Purchase an air conditioner with the same tonnage as your current model.
  • If your energy bill is unexpectedly high, you might need to look at your air conditioner’s size.
  • Inconsistent temperatures within the house may indicate an oversized or undersized AC.

However, many do not realize that your current or initial unit is optimized for your space, which is why it’s important to know the difference between BTU vs Ashrae. As a result, focus on buying the best air conditioner available in that size. Also, consider whether you want an air conditioner with high cool vs low cool based on your preferences and climate.

Insider Tip

To discover the tonnage of your current air conditioner, find the number between 18-60 divisible by 12 on the back of your unit.

Comparing a 4 Ton vs 5 Ton Air Conditioner

When you try to determine whether you need a 4 or 5-ton air conditioning unit, you will need to find the tonnage of your current unit, otherwise, your A/C unit will run all the time. To do this, you’ll need to understand the differences between a BTU and a ton to find the best unit for you. Your contractor should also know the proper size for your house. However, if you would like to figure this out yourself, we have a great guide if you are wondering how many ton ac do I need.

One British thermal unit (BTU) equals the amount of energy necessary to change the temperature of a pound of water by one degree. In terms of air conditioners, one ton represents a unit with a capacity of 12,000 BTUs/hour. So, a 4-ton unit has a capacity of about 48,000 BTUs/hour.

When you look at the back of the air conditioner, there should be a number between 18-60 that is divisible by 12, meaning it results in either a whole number or one ending in .5. The resultant number is the tonnage of your air conditioner, something your contractor may ask about when you call. If you can’t find the number, you need about one ton for every 500 square feet of area.

You might also consider whether an aluminum vs copper coil air conditioner is suitable for your house.

Problems with an Oversized Air Conditioner

Intuitively, you may think that an oversized air conditioner, like a 5-ton AC unit in the space for a 4-ton model, will more effectively cool your area. However, several issues may occur with the wrong size air conditioner, including improperly cooled space, extra humidity, or higher electricity costs.

If your unit runs for a short time, such as a few minutes, before turning off abruptly, you may have a product that is too large. A properly sized AC runs for consistently timed cycles and keeps your entire home cool. Inconsistent temperatures between rooms or extra humidity can also indicate you need a smaller unit because the cycles do not remain consistent. These shorter cycles require more power to start, so your energy bill might also be higher.

Problems with an Undersized Air Conditioner

Using a 4-ton air conditioner in a space that needs a 5-ton model also has its problems. Smaller units have to work harder to cool the room and house. That said, they are not designed for larger spaces, which will cause them to run continuously or almost continuously.

Plus, these units may never cool the home evenly or adequately. Although other issues can cause this problem, you may have an undersized AC unit if you have found no issues with your filter, coils, condensate drain line, and refrigerant container.

Like an oversized unit, your energy cost might also be higher than expected, especially during the summer. As the temperature rises, your model has to work harder and longer.


An over- or undersized-air conditioner increases the amount of electricity used in your house, so make sure you get a unit that is appropriately sized.


What is a BTU?

A British thermal unit (BTU) is the amount of energy it takes to cool needed to change the temperature of one pound of water by one degree.

What is a ton of refrigeration?

A ton of refrigeration is equivalent to 12,000 BTUs per hour.

How many tons of AC per square foot?

You should have about one ton for every 500 square feet. Knowing your square footage helps determine the correct size for your equipment and energy usage.

STAT: Since an inadequate air conditioner won’t complete a full cycle, the extra expended energy will result in higher energy bills. (source)

Alexis Labadie Profile image