The average 8000 BTU air conditioner uses between 660 and 1000 watts to operate, but you can also do your own calculations for your specific unit.
Different types and models of air conditioners use varying amounts of power to run, depending on a number of factors.
To determine the exact number of watts that your 8000 BTU air conditioner uses, you can use average estimates, or you can use manufacturer specifications, your own calculations, or a watt meter.
Air conditioner energy usage
Air conditioners have become such a popular addition to living rooms, bedrooms, offices, and other spaces, that manufacturers have developed wide ranges of AC types and sizes so that most people will be able to find the air conditioner that is right for them and their space.
As a result, the energy consumption of each air conditioner will vary based on the type of air conditioner you have, its power and capacity, the model’s energy efficiency, and many more contributing factors.
How many watts does an 8000 BTU air conditioner use?
Although air conditioners differ from one model to the next, there are certain measurements and metrics that are important for owners to know about their air conditioners.
The wattage of an air conditioner model is often not as widely advertised and readily accessible as the BTU and SEERrating, but it is important nonetheless, as this is a measurement of the cooling capacity of your air conditioner.
More specifically, a higher wattage means that power moves more quickly through the system of your air conditioner.
You can also use the wattage of your air conditioner to determine the cost of running the unit, which is why this measurement is important to most owners.
The average 8000 BTU air conditioner has a wattage of between 660 watts (W) and 1000 W, but this will be unique to each air conditioner.
Since this aspect is not as widely advertised and can differ substantially from one model to the next, you can determine the wattage of your specific 8000 BTU air conditioner in one of following three ways:
 The first way is to look at the manufacturer specifications of your specific model for the wattage
 The second way is to calculate the wattage using other widely advertised measurements of your air conditioner
 The last way requires a watt meter to determine the wattage that your specific unit uses
Finding watts with manufacturer specifications
If you are lucky, the manufacturer of your air conditioner will publicise its wattage widely. This means that you can find the watts listed on the label, in the user manual, or even on the website from which you bought the unit, as with these examples:
Specific 8000 BTU models  Available on Amazon  Type of air conditioner  Wattage (watts) 
Whirlpool 8000 BTU Air Conditioner with Remote  Portable air conditioner  1250 Watts  
Keystone LCD 8,000 BTU Air Conditioner  Window air conditioner  666 Watts  
GE Air Conditioner 8000 BTU  Window air conditioner  695 Watts  
BLACK+DECKER 8,000 BTU Portable Air Conditioner with Remote Control  Portable air conditioner  950 Watts 
These examples fall in line with the averages mentioned above, but also illustrate how important it is to examine your specific 8000 BTU air conditioner model if you want an accurate figure of watt usage.
Calculating the watts of your 8000 BTU air conditioner using other measurements
If your manufacturer does not list the amount of watts that your specific 8000 BTU air conditioner model uses, you can estimate the wattage using the unit’s other measurements. In some cases, you can calculate the wattage by multiplying the amps and the voltage of your unit.
For instance, in the case of this 8000 BTU BLACK+DECKER BD08WT6 Window Air Conditioner with Remote Control, the wattage would be 115 V multiplied by the 5.8 A, which equals 667 watts of power.
You can also divide the BTU of your air conditioner by the EERrating. As an example, this Keystone LCD 8,000 BTU Window Mounted Air Conditioner model’s wattage will be 8000 BTU divided by the 12 EERrating, which equals 666 watts.
These options are available for purchase on Amazon 

Using a watt meter to determine the wattage of your 8000 BTU air conditioner
The most accurate way to determine how many watts your specific 8000 BTU air conditioner uses, is to use a watt meter to take measurements of your unit’s power usage.
Watt meters, like this Poniie PN2000 Plugin Kilowatt Electricity Usage Monitor, are plugged into the power socket and then your air conditioner is plugged into the watt meter. This meter will then give you a digital readout of the amount of kilowatts that your air conditioning unit uses per hour.