Window Air Conditioner Size Guide
A Guide for choosing the right size AC unit
Over the years, the most common question we hear is “what BTU size air conditioner is right for me?”. It’s a common question because there are so many variables that go into choosing the right size. We created this guide to help you make the right choice.
Why Choosing The Right Size AC is Important
What’s the big deal, right? It’s a big heavy piece of metal that goes in the window and makes cold air! While it’s true that they are heavy, choosing the wrong size can cause your room to be way too hot, or way too cold.
- Too Small: If you buy or rent an air conditioner that is too small for your room, the unit may not be effective at all in cooling your room. Cold air might be coming out, but the appliance will be over working (running up your electric bill) and take hours to make the room slightly cooler.
How Do I Determine What BTU AC I Need?
There are two steps to finding the right sized window AC:
Step 1:
Start by determining your room size. How large is the room(s) you are trying to cool? If you know what size room you have, you can reference the following chart:
| Square Feet | Room Type | Recommended AC Size (BTUs) | AC Size (BTUs) for extra cold |
| 150 sqft | Small Bedroom | 5000 BTU | 6000 BTU |
| 250 sqft | Medium Bedroom | 6000 BTU | 8000 BTU |
| 350 sqft | Large Bedroom | 8000 BTU | 10,000 BTU |
| 450 sqft | Medium Room | 10,000 BTU | 12,000 BTU |
| 550 sqft | Large Room/Studio | 12,000 BTU | 15,000 BTU |
If you don’t know what size your room is, you can use this guide to estimate:
Bedroom or home office
Primary bedroom or playroom
Living room, family room, or open plan
Step 2:
Step up 1-2 sizes in the chart above if:
- The room or apartment is on the 2nd floor or higher. Heat rises, so you will want to go up one size in the chart above to account for that.
- The room or apartment is on the top floor. The dark roof absorbs sunlight so you will need a higher BTU AC to manage the extra heat.
- You receive direct sunlight (greenhouse effect). Usually if your windows are west-facing for the afternoon sun, you’ll want to jump up a size in the chart above.
- You like it especially cold.