We all like comfort - when it's hot, it's hot and there's no comfort in that. Having your house the right temperature makes life oh so pleasant and you definitely sleep better and longer when you're cool. So how big (or small) of a unit do you need? Air conditioner sizes are measured in tons and range from 1 ton to 5 tons. The higher the tonnage, the bigger the air conditioner and the more cooling power it has. But again, bigger isn’t always better. You want the air conditioner that’s right for your home.