How to Choose an Air Conditioner

Keep cool with an air conditioner. Before you buy an air conditioner, consider the space you're shopping for; do you need to cool your entire home or just a specific room? Do you have the proper electrical requirements? At Homedepot.ca we can help you find the perfect air conditioner to keep cool this summer.

Types of Air Conditioners

Portable Air Conditioner

Portable Air Conditioner

Portable air conditioning units are a great choice because they can be easily moved from room to room depending on your daily needs. Most portable air conditioners have the capability to cool a room up to approximately 300-400 square feet in size. Although these units offer the convenience of portability, they typically cost more to purchase and operate.

Window-Mounted Air Conditioner

Window-Mounted Air Conditioner

Window-mounted air conditioners can comfortably cool between 300 and 1600 square feet. Horizontal window-mounted units are designed to fit a vertical sliding or hung sash window, while vertical window-mounted units are designed to fit a horizontal sliding or casement window. Window-mounted units can also be easily removed and stored with the change of seasons.

Through-the-Wall Air Conditioner

Through-the-Wall Air Conditioner

The real advantage of through-the-wall air conditioners is that they can be installed and sealed permanently so less cool air leaks back outside, which will save you money in the short and long run.

What Size Unit Should You Buy?

The key is to determine exactly the right size for you. Too small an air conditioner will continuously run and will not adequately cool a room. Too large a unit will tend to cycle off too quickly. The unit will not properly remove moisture from the air and may freeze, resulting in a higher energy bill. Ask a qualified air-conditioning technician for a thorough analysis so that you get exactly what you need.

Choosing the Right BTU

Selecting the right BTU (British thermal unit) for your room size will ensure you have the most energy-efficient cooling system for your home. BTU ratings are numbers that tell you how quickly and effectively a unit can cool a room. Generally, ratings range from 5,000 to more than 20,000 BTUs. When an oversized air conditioner is used in a small space, it cycles on and off and wastes energy, decreasing the unit’s ability to dehumidify the room. Alternatively, if a unit has too few BTUs, it will not be able to cool a large space efficiently.

It’s important to consider factors such as ceiling height, room insulation, sun exposure, location and your area’s climate when choosing a unit with the right BTU rating. Here are some helpful tips:

  • Rooms with excessive sunlight should have a unit with 10% more BTUs than what is required by the room size.
  • When placing a unit in the kitchen, select one with an additional 4,000 BTUs than what is required by the room size.
  • For higher traffic rooms or rooms that regularly contain more than two people, add an additional 600 BTUs per person. 

BTU Calculator for Window Air Conditioners

Room Size Recommended BTUs
Between 150-350 square feet
5,000-8,000 BTUs
Between 400-550 square feet
9,000-12,000 BTUs
Between 600-1,000 square feet
12,000-18,000 BTUs
Between 1,000-1,500+ square feet
24,500 BTUs

BTU Calculator for Portable Air Conditioners

Room Size Recommended BTUs
Max 200 square feet
8,000 BTUs
Max 300 square feet
10,000 BTUs
Max 400 square feet
12,000 BTUs
Max 600 square feet
14,000 BTUs

Before You Buy

  1. 1 Calculate your room size

    To figure out the square footage of the room, multiply the length by the width (in feet).

  2. 2 Check your connections

    Find the power source (such as a nearby outlet) and make sure to match the unit to that outlet. 

  3. 3 Measure to fit

    Measure the height and width of the opening and check the dimensions of the air conditioner to make sure it will fit.

Extra Features

Here is a list of features that people commonly look for when purchasing a new air conditioner:

Easy-Access Filters
Makes cleaning or replacing the filter easy.
Humidifier/Dehumidifiers Use the dehumidifier in the summer to remove dampness from the air and the humidifier in the winter to return moisture to the air.
Multiple Cooling and Fan Settings Allows you to adjust the device according to your needs.
Slide-Out Chassis Allows for easy installation.
Energy-Saver Options Will save you money on your energy bills and it's a better choice for the environment.
24 Hour On/Off Timer Enables you to program the air conditioner to turn on and off at specific times.
Remote Control Gives you the option to adjust the temperature without getting up.
Quiet Operation Sound sensitive air conditioners cool the house without all the noise.

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