Wattage Vs. Surge Wattage for a Window Air Conditioner

Energy

• The amount of energy that an air conditioner uses is closely tied to its starting wattage and its running wattage. The higher the number of British thermal units or BTUs used by the air conditioner, the more that both wattage numbers will be. For instance, Rheem indicates a 10,000-BTU air conditioner requires 3,600 starting watts and 1,200 running watts. A 12,000-BTU air conditioner, on the other hand, requires 9,750 starting watts and 3,250 running watts. These numbers are important to know for two primary reasons. First, you need to know how much money your air conditioner costs you every time that it starts. If you have an air conditioner that has a high starting wattage and turns off and back on frequently, you may end up paying more on your electrical bill in the long run. Secondly, in the event of an emergency, you need to know if your generator can handle the load.

Window Units

• Knowing the difference between the surge wattage and the running wattage of your window air conditioner will help you with emergency preparedness. Generators run on a limited capacity in that they can only handle a limited number of electrical devices running at the same time. The starting wattage rating of your generator will tell you whether it can handle your air conditioning unit. The same is true in regard to the running wattage, of course, but without enough power to start it, the issue of running it is moot. Regardless, the air conditioner's wattage will affect the amount of time that your generator will run before requiring fuel.

Central Air Conditioners

• Knowing the running and starting wattage of your window air conditioner can help you calculate and determine which of your appliances and other essential electrical components you can run at one time. In many cases, it is far more feasible to run a window air conditioner on a generator than it is to power a central air conditioning system with a gas generator. Central air conditioners require more starting wattage than do window units. A 10,000-BTU central air conditioner will require 4,500 starting watts and 1,500 running watts. A 40,000-BTU system requires 18,000 starting watts and 6,000 watts to continue running.

Considerations

• When determining whether or not to power a central air conditioning system with a gas generator, prioritize to determine what your most important electrical items are. You may be able to run your window air conditioner in a limited capacity on a low setting to keep from putting too much of a drain on your generator. Avoid running it on a setting that causes the compressor to cycle on and off, as this will require more electrical power.