Would you buy a NEW CAR and put on your OLD TIRES? That’s just what you are doing if you buy a new Air Conditioning system and leave you’re your old leaky worn out duct work! Like tires on a car take you where you want to go, the ducts carry the air your system is heating or cooling where you want it to go. If you have the most expensive, most efficient AC and Heating system in your attic, producing clean refreshing air and then that air has to pass through 20 year old, dirty, leaky ducts to get in to your home and lungs, how clean is that air when it gets there? Or how much of the air that you are paying for end up in your attic and doesn’t even make it into your home? There are other factors here as well, if your system and duct work is located in the attic, as the majority of our systems here in the south are.
Your indoor equipment, I will refer to as your air handler, removes (returns) air from the house, passes it through the cooling coil or heater (conditions it) and puts it back (supplies) into the house. Assuming no air leaks, the same amount of air that is removed from the house goes back into the house and the system is balanced and efficient. However, most systems have leaks, so what does that mean? If the leaks are on the supply side of the system, more air is removed from the house then is put back in, creating a negative pressure in the home. When this happens the many small leaks around the doors and windows (among other locations) will literally allow dirty unconditioned air to be “sucked” into the house. On the other hand, if there are more leaks on the return side of the system, then dirty unconditioned air is drawn into the system causing the blower, coils, heater, etc. to become dirty and inefficient as well as causing the system to over work to deal with the extra unconditioned air. And if you have leaks on both sides of the system, as is common, well you can imagine how much money is being wasted. If you look at the pay back cost, not counting increased comfort, less money on cleaning and maintenance, then replacing old ducts can give you a great bang for your buck.
There are many types and levels of duct work available. In future articles I will discuss these various types and the pros and cons of each.