Smallest Air Conditioners — How Low Can You Go?

In the heat of summer, finding relief in a home or apartment without central air conditioning can quickly become a costly endeavor. Finding the smallest and most efficient AC unit for your space then becomes a top priority.

We’ll take a look at the smallest air conditioner sizes that can accommodate your space by looking at the physical dimensions of these units, the size of your room and the smallest AC units in terms of their cooling capabilities.

Smallest Air Conditioners: BTUs and Dimensions

Choosing an AC unit begins with assessing its efficiency. Air conditioners are measured using a standard called British Thermal Units, or a BTU rating, which measures your unit’s cooling capacity. The larger the room, the higher the BTU your AC will need to efficiently cool the space. 

In general, a room between 100 to 250 square feet will need an AC unit with 5,000 to 6,000 BTUs. Rooms from 250 to 400 square feet will need between 6,000 and 8,000 BTUs. 

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Of course, the higher the BTU the better the unit will be at cooling a room, even if it’s more power than your room requires. But these parameters are a good starting point outlining the minimum BTUs you will need for your space. 

AC Units for Tight Spaces

If you’re looking to install a small air conditioner in a tight space, you’ll need a compact unit. There are a few types of AC units you can consider as you hunt.

Small window air conditioners have a slim profile and can make these units ideal for tight offices or attics, for example. Portable AC units also come in smaller sizes but are often considered less efficient as some hot air is returned to the room as it works. Battery-powered air conditioners are also an option although these units will typically drain power quickly and require a new battery or charge. 

When it comes to window AC units, you can typically find models in the following dimensions and capabilities: 

Model A:

• Dimensions: 14.2″ W x 16″ D x 12.8″ H
• BTU: 5,000
• Suitable for rooms up to 150 sq. ft.

Model B:

• Dimensions: 16″ W x 15.6″ D x 12.8″ H
• BTU: 6,000
• Suitable for rooms up to 250 sq. ft.

Portable air conditioners are a good option if you want to be able to use them in various rooms or even on the go in hotel rooms or RVs when you travel. These units don’t require permanent installation and can be moved quickly and easily from room to room. You should be able to find these units in the following sizes: 

Model C:

• Dimensions: 13.5″ W x 13.5″ D x 24.2″ H
• BTU: 8,000
• Suitable for rooms up to 300 sq. ft.

Model D:

• Dimensions: 12″ W x 13″ D x 28.3″ H
• BTU: 10,000
• Suitable for rooms up to 350 sq. ft.

Small Rooms Require Fewer BTUs

If you have a small room of 250 square feet or less, a window air conditioner with 5,000-6,000 BTUs should be sufficient to cool the space without wasting power. As you shop, look for models that have compact dimensions to ensure a snug fit in your window.

If you need to find a window AC unit for a smaller window, look for units described as having slim profiles. Model A and Model B are common dimensions for such units.

There are also small options for condenser units and ductless mini-split air conditioners. These types of AC systems have a small outdoor unit which you mount on a wall or stand and they are designed for smaller areas.

Finally, many portable AC units are designed small so they can be easily moved, but their size is also ideal for tight spaces. Models C and D are good examples of common dimensions for these kinds of units, which can provide efficient cooling without taking up much floor space.

Start Shopping

Finding the smallest air conditioner size for your room that fits your needs is the best way to go about efficiently cooling a space. As you hunt, be sure to consider the BTU rating, dimensions, and portability so you can make the best choice for your situation. 

You can also save money with the right unit by qualifying for certain government rebates. Find out more on our HVAC resources page.