A window AC unit is better than central AC when you live in a smaller space or only need it for a bedroom or studio apartment. As window ACs are more compact, they do not use as much energy. However, if you need AC supplied to the whole house, central AC is more energy-efficient than operating several window units throughout. If you live in a temperate climate with few hot days, a window unit could save you more money than running A/C year round but keep you cool when you need it most.\r