There’s a lot to be said for buying an older home. Besides their charming exteriors, they’re often well built with durable materials and sturdy construction. But one thing older homes aren’t usually known for is a good air conditioner. Even in our steamy region, some homes may never have had a central A/C installed or, if the home has some type of A/C, it may be time to upgrade it to a system that’s more efficient. Read on to learn what’s involved in adding central A/C to older homes.
Determining the Scope of the Project
Adding central A/C to older homes can be expensive, involving the addition or renovation of ductwork, upgrading the electrical system with a dedicated 230-volt circuit, increasing the size of the blower, changing out old registers for those sufficient to handle greater air flow and sealing the home envelope and the ductwork. That said, the advantages are many. If you’ve been using window units, you may be fed up with how unsightly and how noisy they are. Plus, running several window units isn’t particularly efficient, nor will they do the best job of cooling the home.
To Add or Not to Add Ductwork
Adding central air conditioning or even replacing an old central air conditioner usually involves installing or replacing ductwork. The ducts may have already been installed for a furnace or an aged air conditioner that needs to be replaced. If the home has had an older central air conditioner and ductwork is present, it may not be able to handle airflow for the new system.
Most often, ductwork is installed in an attic or basement. Sometimes contractors hide ducts behind walls or in the rear of closets. Other possibilities are lowering a ceiling to conceal ducts or building out a wall to hide the return and supply ducts. This kind of construction can be expensive and may ruin the aesthetics of your interior. Wherever it’s installed, the ductwork should be designed with a mind to efficient delivery of cool air and should be sized with industry software called Manual D so that it’s a good match for the A/C.
You can save money on ductwork installations and avoid having an extensive construction experience going on in your home if you go with a ductless mini split system. These systems, as the name implies, don’t require ducts. They may be a bit more expensive than conventional air conditioners, but they’re very efficient and installation is very fast. They consist of an air handler and evaporator unit inside and a condenser/compressor unit outdoors, all connected by refrigerant and power lines. As many as four air handlers can be installed with some of these systems, which are in fact heat pumps, only without ductwork to distribute the air.
Another option is the high-velocity system. These use smaller, flexible tubing rather than standard ducts.
Selecting an A/C
The most important factor in adding central A/C to older homes is properly sizing the new system. Find a contractor who uses Manuals J, S and D to determine what size is right for your home. The contractor will input information on square footage, the number of people in the home, windows, climate, and other details to determine what cooling load the A/C should bear, how big the system should be and the volume of air the ductwork will need to accommodate.
You’ll also have to decide how efficient you want your cooling system to be. Air conditioner efficiency is measured by seasonal energy efficiency rating (SEER), or how many British thermal units (BTUs) an A/C removes for each watt of electricity used. The higher the SEER, the more efficient the air conditioner. A high-efficiency A/C tends to be of better quality, should last longer, has more safety features, has lower operating costs and uses less electricity than those with a lower rating.