9000 BTU Window Air Conditioner | Room Size, Electricity, & Best Options

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With the window air conditioners coming in different sizes, picking a unit that is ‘just right’ for your room can be difficult. However, matching your air conditioning to your room size is crucial; otherwise, you may never able to enjoy desired comfort levels. An air conditioner that’s too big for a room may fail to properly dehumidify it while an undersized unit may not adequately cool it. Generally speaking, for smaller rooms, a 9,000 BTU window air conditioner can be a good option.

In this article, we’ll discuss the 9,000 BTU window air conditioner in detail. So, if you are looking to buy a 9,000 BTU window AC, this post is just for you.

What Size Room will a 9000 BTU Unit Cool?

The cooling capacity of an air conditioner is expressed in tons and refers to the amount of heat (that is BTUs) it can remove in an hour. So, when the manufacturer says an air conditioning unit is of 9,000 BTU, what it means is that the AC can remove 9,000 BTUs in an hour.

One-ton AC can remove 12,000 BTUs (British Thermal Units) in an hour. This means a 9,000 BTU air conditioner has a cooling capacity of 0.75 tons.

And as a rule of thumb, one ton of AC can sufficiently cool 600 square feet. This means a 9,000 window BTU air conditioner (0.75 ton) is adequate for a room size of 450 square feet.

However, keep in mind that several other factors can impact the cooling efficiency of an air conditioner. For example, if you live in an extremely hot city, such as Las Vegas, a 9,000 BTU unit may be to cool only 400 or even 350 square feet. Poor insulation, too many windows, and too many electrical appliances in the room are some of the other factors that negatively impact your AC’s cooling capacity.

How big is a 9000 BTU Window Unit?

A 9,000 BTU window air conditioning unit has a cooling capacity of 0.75 tons. You can expect a 9,000 BTU window unit to weigh about 75 pounds. That said since the weight and dimensions vary from one model to another, please check the product details of the selected product to know its size and weight.

How Much electricity does a 9000 BTU Window Air conditioner Use?
A 9,000 BTU window air conditioner uses 900 watts.

What size breaker do I need for a 9000 BTU Air Conditioner?
What size circuit breaker you need depends on the unit you are installing. The breaker does the all-important function of protecting the wire and your device. The installation guide should tell you the size of the circuit breaker you should use. If it says the breaker should be a maximum of 20A, you should install a 20A breaker.

3 Great 9000 BTU Window Air Conditioner Options

LG 8,000 BTU Window-Mounted Air Conditioner

Affordable and energy-efficient, this LG model can efficiently cool a room that’s 340 square feet or smaller. It has 3 cooling speeds and comes with an Auto Start feature, which can prove handy in the event of a power outage.

Emerson 8,000 BTU Window-Mounted Air Conditioner

This Emerson model is a cost-effective solution for cooling and dehumidifying a room-sized 250 to 350 square feet. In addition to flexible cooling options, it features a programmable 24-hr on and off timer.

Whirlpool 10,000 BTU Window-Mounted Air Conditioner

This Whirlpool model is a powerful yet cost-effective air conditioner. It can efficiently cool a room that’s 450 square feet or smaller and come with a host of advanced features, such as sleep mode, eco mode, and a 24-hr on and off timer.

9000 BTU Window Unit Vs Mini Split Options

Can’t decide whether a window air conditioner or a mini-split will suit your home better? Both of these offer unique benefits. Therefore, which one you should install depends largely on your needs, budget, and personal preferences. You can read this article to learn more about finding the right size mini-split unit for your home.


It’s no secret that a mini-split air conditioner cost significantly more than a window unit. How much more? A 9,000 BTU mini split AC may cost 1.5 to 2 times more than a window unit. However, mini-split air conditioners are more energy-efficient. As a result, they can prove to be cheaper in the long run.


Window air conditioning units are fairly simple to install. This is something you can even do yourself, provided you take the necessary safety requirements. That said, it is always to let professionals do this because even a small mistake during the installation can prove costly. On the other hand, installing a mini-split air conditioner is a specialist job and can take up a day.

Energy Efficiency

When it comes to energy efficiency, a mini-split air conditioner beats its window counterpart by a country mile. The former is up to 40% more energy efficient. So, if cutting down the energy costs — and by extension, your carbon footprint — is a priority, you may be better off installing a mini-split unit in your home.


There’s no denying the fact that for all their enticing benefits — low upfront cost and simple installation — window air conditioning units have some glaring weaknesses. Not only they are considerably less energy efficient than mini-split units, but they can also be noisy. In contrast, mini-split units are generally very quiet. If it is installed correctly and in an optimal location, it will not cause any disturbance.


Mini-split air conditioners last significantly longer than window air conditioning units.


Because a window AC has a single unit, it is easier to service and cheaper to maintain. A mini-split air conditioning unit, however, has two units. As such, it is more difficult to service and requires periodic maintenance for optimal performance.