How much electricity does a window AC consume?

We all want to save money on electricity at the moment. Understanding how much energy your AC uses is a core part of cutting costs.

So, we’ll cover exactly how much electricity a window AC consumes in this article.

How much electricity does a window AC consume?

A window AC uses 900 – 1,400 watts of electricity an hour. That’s.9 – 1.4 kWh (kilowatt hours). A standard window AC offers 7,000 – 13,000 BTUs of cooling capacity. It can cool a single room or a one-bedroom apartment. 

Smaller units produce just 5,000 BTUs of cooling power. They are suitable for small rooms like bedrooms. A 5,000 BTU Window AC uses 600 – 700 watts to cool a small room. 

Larger Window ACs can produce 24,000 BTUs of cooling power. They can cool a space of 1,400 – 1,500 square feet, like a typical three-bedroom apartment in the US. A 24,000 BTU Window AC uses 2,500 – 2,800 watts of power. Larger air conditioning units tend to be less efficient than smaller ones. 

A BTU is a measurement of thermal energy. It’s the amount of energy needed to change the temperature of one kilogram of water by a single degree Fahrenheit. There’s a direct conversion rate between BTUs and watts. A single watt (W) is equivalent to 3.41 BTUs of thermal energy per hour. However, air conditioners are not perfectly efficient, so the conversion rate varies. 

Air conditioners consume electrical energy and produce thermal energy. They use electrical energy to move thermal energy from inside to outside your home. This allows air conditioners to produce more BTUs than the strict conversion from watts to BTUs.

There’s actually a direct conversion rate between BTUs and watts since both are units of energy.  A single watt (W) is equivalent to 3.41 BTUs of thermal energy per hour. So to convert from watts to BTUs, you would multiply your wattage by 3.41.

But we can’t use this conversion when talking about air conditioning because air conditioners are not perfectly efficient. Some energy is lost in the process of cooling your home. Different air conditioners actually produce BTUs from watts at different rates because some units are more efficient than others.

For example, let’s say we need 24,000 BTUs of cooling power. We could convert from 24,000 BTUs to 7,032 watts. But a Window AC only uses 2,500 – 2,800 watts to produce 24,000 BTUs of cooling. How is this possible?

Because air conditioners generate thermal energy while using electrical energy. In order to create cold, an air conditioner need more than simply electrical energy. Instead, it transfers thermal energy from within your house to the outdoors using electrical energy.

This prevents the thermal energy from being destroyed, which is not conceivable. It has relocated. By using this theory, air conditioners can generate more BTUs than they could have by strictly converting watts to BTUs.

The coefficient of performance (COP) of air conditioners evaluates how energy-efficient they are. The coefficient of performance (COP) is only a ratio of the watts of thermal cooling provided by an air conditioner to the watts of electrical energy it uses.

The majority of air conditioners have a performance coefficient that ranges from 2 to 5. Greater efficiency is indicated by a higher COP.

Let’s revisit our illustration. We are aware that 7,032 watts of thermal energy are needed to produce 24,000 BTUs of cooling power. An average window air conditioner expels 7,032 watts of thermal energy from your residence per hour with 2,500 watts of electrical energy.

Thus, the COP of your window air conditioner is 7.032/2,500, or 2.81. That isn’t particularly efficient, but it shouldn’t come as a surprise considering how inefficient most bigger window ACs are.