Air Conditioner: What Size Do You Need?


When you think of summer, it’s easy to remember the heat and humidity. One way to cope with the sweltering temperatures is by using an air conditioner. But before you can install your AC unit, you need to figure out what size you’ll need for your home or office space.

Air conditioners come in many different sizes and can be difficult to decide what size you need. You may not know which BTU your home needs, or how much square footage an air conditioner should cover. To help answer that question we’ve created this blog post which will explain how you can calculate the right size for your needs!

Before deciding on what size, you need for an air conditioner, let’s take a look at the different types of air conditioning systems.

Different Types of Air Condition

Ductless Air Conditioning

These independent units can be placed anywhere making them a popular choice for homes and offices. Ductless AC systems don’t require any installation of a central duct system, which means it’s extremely easy to install and remove the unit whenever you like! Additionally, since there isn’t a dedicated venting system required with these portable units, it also helps keep costs down. The downside however is that, unlike window or split type air conditioning units, ductless systems cannot cool an entire room. Instead, they only cool single spaces such as individual rooms or cubicles in your office.

Window Air Conditioner

Unlike other types of air conditioners that must be installed through wall openings, window air conditioners can be mounted within a home or office space through a window. Just like ductless AC systems, the installation and removal of your unit are also extremely easy as you only need to install it on the inside of your home or office. It’s very similar to installing a window screen! The downside however is that window air conditioning units can’t actually cool an entire room either since they require dedicated ventilation.

Split Air Conditioning System

One of the most popular types of air conditioners for homeowners and businesses alike, these types of systems use central ducts and vents to distribute conditioned air into different rooms in your home or office. This makes it ideal for cooling spaces larger than those which can be cooled by a single room ac system. Since there isn’t any requirement to install individual vents throughout your home, installation is also much easier. The downside though would be the need to install a central heating system which in turn requires professional installation.

Central Air Conditioning System

As the name implies, these types of systems are installed within your home or business using central ducts and vents to cool spaces throughout your entire building. These are the most expensive to install since they require professional labor for both installation and yearly upkeep however are still widely used by homeowners and businesses that want an efficient way of cooling their property.

Now that you know what type of air conditioning unit you have, let’s begin learning how to calculate the BTU size you’ll need!

How To Calculate BTUs For Your Room or Space Size?

Before choosing an air conditioning unit, you first need to know how many BTUs your home or office will need. This information will allow you to choose the right size of AC unit for your space and effectively keep it cool during hot summer months.

To calculate the number of BTUs needed for a given space, you’ll want to take measurements from both length and width throughout your room or office space. For example, if you have a 600 – 1,000 (Home Square Footage) area, then you need 18,000 BTU. Check out our sizing table below which provides an estimate for how many BTUs are required by different sized spaces:

Home Square Footage BTU Tonnage
600 – 1,000 18000 1.5
1,000 – 1,300 24000 2
1,300 – 1,600 30000 2.5
1,600 – 1,900 36000 3
1,900 – 2,200 42000 3.5
2,200 – 2,600 48000 4
2,600 – 3,200 60000 5


Frequently Asked Questions

How Many BTU Do I need?

To find out the right side of the air conditioner to buy, first, measure your room’s length and width. Then use our table to determine what BTUs are required by your space. However, you should also consider other factors such as filtering capability since this can affect how cool your space will be.

What Room Size Does a 10,000 Btu Unit Cool?

This really depends on how efficiently your home or office is insulated along with the number of windows or doors that take up airflow into or out of that specific room. A rule-of-thumb would be about 20 “BTU per square foot” for very well insulated homes while homes with poor insulation could be as little as 10 BTUs per square foot.

Why do Some Units Have More BTU than Others?

Most units are in the same general range of 9000 to 24000 BTUs based on the space they’re designed to cool. But there are some major differences in AC unit technology. For instance, window ACs cost less and their efficiency is lower than split systems or ductless mini-splits (ductless). These types of technologies usually start at about 12000 BTU and go upwards from there based on size. “High SEER” air conditioners use substantially less energy than standard units by using high-efficiency compressors, fans, coils, and other components that provide greater cooling without requiring more BTUs.

What is the Difference Between BTU and SEER?

The “SEER” (seasonal energy efficiency ratio) of an air conditioner is a measure of how efficient the cooling technology is. A higher number means it uses less energy to cool your home or office resulting in lower utility bills. On the other hand, BTUs quantify how much heat must be removed from any given space by measuring temperature and humidity differences between that space and the outdoors. This measurement does not vary as much as SEER so it’s typically easier for consumers to understand.

Best HVAC Service for your Home

If you are not techy enough and need an expert to come to your home and check for this to figure out how big an air conditioner you’ll need. Then the Congressional HVAC Company is the best one for you. Congressional HVAC company has the best technicians to handle any type of HVAC work at home. They are experts in diagnosing and repairing all kinds of air conditioners. They specialize in both in-home and business HVAC services. They carry all types of air conditioners like windows, split systems, heat pumps, and more. So, you no need to worry about how big or small your system needs to be.


Air conditioners are an important part of any household. You have to decide what size you need, whether it’s for a small bedroom or a large living room. This article has helped you learn about different types of air conditioner sizes and how many BTUs they produce. They also help determine the length of time your unit will run on one tankful before needing more coolant. Hopefully, this information is helpful in deciding which type best suits your needs!

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