If your home needs a new air conditioner, you can opt for a central unit that works through the ducts in the home, a split system unit that blows air out a front panel and which vents directly out an exterior wall, and a window unit. Each has their own advantages and disadvantages, so note a few tips for choosing the best system for your home.

For cleaner air

If you're prone to allergies, breathing disorders, or just want the cleanest air possible with your air conditioner, you might opt for a split system unit. A ducted or central air unit blows air through a home's ducts and then brings with it anything settled in those ducts, including dust, pet hair and dander, rodent droppings, and the like. A split system unit doesn't go through dirty ductwork so the air it circulates is often cleaner overall.

For "light" use

If you actually enjoy the heat or live in a temperate climate and find that you don't need to cool your house very much during summertime, a central air unit may be a waste of money. They are very powerful but if you don't need all that cooling ability, you may be overpaying for a unit you don't really need or use. A split system unit can be good as it's more powerful than a window unit but not as powerful as a central unit, and more affordable as well. 

If you find that you just get uncomfortable at night, a window unit in the bedroom can also be sufficient. Today's window units are usually smaller, more lightweight, and yet more powerful than ever before, so don't assume they're noisy and don't cool very well; a high-quality window unit may be all you need for "light" use of your air conditioner.

For very humid environments

A central air conditioner works to remove heat and humidity in a home as it often has a dehumidifier built into its system, pulling away moisture and condensation in a room. A split system or window air conditioner may not be powerful enough to remove that humidity as these just blow a small amount of cold air into your space. If you opt for a smaller unit in a very humid environment, you may need a strong dehumidifier as well and this can mean an added expense and having to manually empty the unit. For very humid environments, even if it's not always overly hot, a central unit can be the better choice.