How to Install Central Air

If warm weather has you wondering how to install central air, you're not alone. Many people in homes without central air struggle with bulky, noisy window units, wishing for a better way to stay cool. Installing central air removes the noise and hassle, leaving you with a quiet and efficient cooling system.

How To Install Central Air: An Overview

Installing central air into an existing home is a complicated project that requires experience and specialized knowledge. You may be able to save some money by doing parts of the installation yourself, but you'll end up with a longer lasting, higher quality installation if you engage the help of a professional. Here are the steps involved for installing central air:

  • It starts with a calculation. Before you can purchase a central air system, you need to be able to properly size it. A certified air conditioning contractor can give you sizing information after performing a "J-load" calculation. This formula was designed by the Air Conditioning Contractors of America trade group and takes into account the size of your home, the number of windows and doors, the type and amount of insulation and your home's orientation to the sun. With a J-load result, you'll be able to purchase a properly sized cooling unit for your home.
  • How to SEER clearly. The SEER rating (Seasonal Energy Efficiency Rating) of an air conditioning unit measures its efficiency, with a higher number equaling greater efficiency. By federal law, new air conditioning units must have a minimum SEER rating of 13. Higher SEER values typically mean a more expensive unit, but one that will save on energy costs over the long run.
  • The system described. A spilt system, the most common type of air central air system, is composed of three parts. The condenser and compressor, which cool and move the refrigerant, are installed outside, as they generate a lot of heat and noise. The evaporator and fan system, which cools and moves the air, is installed inside-usually in the attic or crawl space of your house. The ductwork carries the air from the evaporator to the rooms of your house.
  • Got ducts? If your house has a forced-air heating system, your existing ductwork is probably sufficient. If not, ducts will need to be run from the evaporator/fan unit to the rooms of your house. For second floor rooms, ducts are run through the attic and dropped to through the ceiling into individual rooms. First floor rooms usually have the ducts run down through second floor closets. Flexible ductwork makes "closet running" simpler, but if you have closets that are heavily used or used by children, insist on sheet metal ductwork as flexible ducts are easily damaged.
  • Electrical supply. You'll need to consult with an electrician to determine if your current electrical supply is powerful enough to handle the extra load a central air system will require. Extra wiring or breaker sub-panels may need to be added for safety and efficiency.
  • Timing. If you have an existing forced air system, a professional installer can have a central air system up and running in a couple of days. If you need ductwork, the installation will take longer and will vary depending on the complexity of your floor plan.
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