Adding Air Conditioning to Existing Systems

Looking for a Central Air Conditioning Quote? Click Here

Central Air Conditioning 

While many older homes are equipped with forced hot water or electric resistance heating systems, today houses are increasingly built with forced hot air in place. This takes the form of a central furnace, generally in the basement, which heats air that is consequently sent throughout the house via a series of ducts and vents. If this is the setup in your home, it is possible to only add an air conditioning unit and use your existing ducts to cool your home. The following changes will need to be made: 

  1. Installing an evaporating/cooling coil in your furnace
  2. Adding a condensing unit (the AC itself) outdoors
  3. Connecting the two with refrigerant lines

This is the easiest situation possible for Air Conditioning installation. In general, this will cost you around $3,500 - $4,000 for equipment and installation, should take no more than 2 technicians and shouldn’t last longer than 3 days.

Possible Modifications

However, there are a few modifications that might be necessary. Depending upon your home’s age and construction, your ducts might not be the right size. Interestingly, the older your home, the better suited it might be to using existing ducts. As heating technology has developed in the past century, ducts and vents have decreased in size. However, Air Conditioning requires slightly larger ducts. Consider this when speaking to a contractor. 

Other modifications that might be necessary in addition to changing the size of some ducts include: 

  1. Increasing the size of your furnace blower (Air Conditioning requires more air than heating)
  2. Sealing ducts to cut down on leaks
  3. Installing new vent registers. By increasing the size of your register openings by  just one quarter of an inch, you can admit 15 – 24% more air.)


Though you should always consult with a professional, you might be able to seal some minor holes in ducts yourself. Learn more at the EPA’s EnergyStar website.

How can I find out more information?

When you Request a Central Air Conditioning Quote one of our recommended Air Conditioning specialists will give you an estimate on your Home Improvement project and will help review your options to make the best possible choice regarding your particular needs and budget.