Window units effectively cool and dehumidify up to two rooms at a time when installed correctly. Instead of consistently cooling the entire square footage of a property, window units use up only enough electricity to focus on small areas of a home. While the overall cost might be less up front, adding multiple window units throughout a home can be as costly, if not more so, than central air conditioning units. Looking only at cost efficiency when comparing window units to central air conditioning, it all comes down to the square footage of a property you are cooling and how many window units are running at any given time.
Central air conditioning can be installed in any home, but does require bulky ductwork and a larger outdoor unit, making them more expensive than window units up front. While window units base cost efficiency on Energy Star efficiency levels, central air is rated on a SEER (Seasonal Energy Efficiency Rating). The higher the SEER rating on a central air conditioning unit, the better the energy efficiency, which puts the cost of operation on par with multiple window units.
Cost savings on air conditioning come down to two factors: temperature control and size of the property. The lower you set the thermostat on a window unit or when using central air, the higher your electricity bill will be. You must also consider the variations in temperature throughout a property when using window units. Even though two rooms might be comfortable, the rest of the house is sweltering. Cooling off different rooms at different times of the day comes with cost and inconvenience that might not be worth the small savings of using window units opposed to central air.
Central air is a highly desirable feature for homebuyers, especially in warmer climates. Window units block out sun and views with their bulky size. Due to decreased interior and exterior aesthetics resulting from window units, homebuyers typically opt for central air. In fact, window units can detract from the overall value of a home at times, whereas central air nearly always adds to it. This is important when considering the prospect of selling your home.