Central air conditioning is common in the United States, but ductless or mini-split systems are becoming more and more popular. Both systems have an indoor compressor or condenser and an indoor unit. Ductless systems can have more than one indoor unit and a small conduit connects the components instead of ductwork. Here’s some more information about the cost differences and other characteristics of central and ductless air conditioning.
Ductless Mini-Split System
Advantages: As implied by their name, the ductless mini-split system does not require ductwork, making it the more convenient cooling option for older buildings with thick walls. It basically keeps your room temperature at a constant temperature, unlike an air conditioning unit that goes on and off throughout the day. In the winter, the system works in reverse by absorbing heat from the outside air and moving it indoors to heat your home, too.
Their compact size allows for greater flexibility in temperature zoning—air conditioning is limited to the rooms in which the air handlers are located. These systems tend to run quieter than central air conditioning systems, and are easier to install. Some ductless mini-split models have the highest efficiency rating of any type of air conditioning system.
Disadvantages: Although a ductless mini-split can save you money in the long run, the initial installation will usually be more expensive than for a central air conditioning system with the same capacity. Improper sizing or placement can mean that your unit runs less efficiently. There are also some homeowners who have aesthetic issues with a wall mounted unit.
Central Air Conditioning System
Advantages: If your goal is to keep your whole house cool, central air conditioning is most likely your best option. With newer models, you can count on efficient, cool and comfortable temperatures and lower humidity.
The system is also virtually invisible, and it adds value to your home.
Disadvantages: As with the mini-split system, you can run into cost problems if the unit has not been properly sized. (However, the upfront cost is considerably less to just replace an existing system with a new central air system rather than with a ductless mini-split system.)