Air conditioner efficiency depends on a lot of factors, such as how efficient your home is, what you’re using the air conditioners for, how large your house is, how many people live in your home, etc. However, if you typically use only one air conditioner at a time in the room you’re spending the majority of your time in, then yes, it will likely be more efficient to have two air conditioners.

If you’re using both air conditioners at the same time, it probably won’t be more efficient unless you have a very large house because you’ll be drawing a lot more electricity. In the case of a very large house with a big family, you’d likely be better off with a heat pump or a central air conditioner.

Whichever air conditioning system you choose, look for a heat pump or central air conditioner with the highest Seasonal Energy Efficiency Ratio (SEER) you can afford or a room air conditioner with the highest Energy Efficiency Ratio (EER) you can afford. In the long run, the more money you spend on an energy-efficient system, the more you will save, and the difference in savings will be significant.

A couple other incentives to look into are the $25 room air conditioner rebates offered by Pepco Energy Services and the federal Residential Energy Efficiency Tax Credit, which is designed to cover up to 30 percent of the system and labor costs for your new air conditioner.