Homeowners ask me all the time if they really need new ducts when we replace their heating and air conditioning system.

The answer, almost always, is a resounding yes and here’s why.

The duct system is largely responsible for what you actually feel when you heat and air condition your home. It doesn’t matter what size A/C unit you have 3 ton, 4 ton, etc or how efficient your furnace is if that air doesn’t get into your home. You are paying good money to have hot or cold air added to your home so that you can be comfortable. I would even go so far as to say that you want your home the most comfortable it can be at the lowest possible cost. And that combination is largely a result of quality design and installation of your ducts.

Consider this, the average heating and a/c system delivers 55% of its rated capacity, or just a touch over 2.5 tons of cooling on your 5 ton system. That number comes to us from the National Comfort Institute. We do hundreds of tests a year and see that number or worse so often that we are shocked when we see anything higher than 70%. They also tell us that after you go out and pay good money for a new high efficiency unit, you are still only going to get 57% delivered capacity. So basically, you’ve got a great new unit that you are driving around town with one foot on the gas and one on the brake. New ducts done right releases that brake.

The biggest culprit in the demise of your systems delivered capacity that we see on a day-to-day basis is returns that are too small or just poorly thought out. Think of your heater and the fan that is in that heater as the heart of your system and the ducts as the lungs. If you can’t get enough air into the system, the heart can’t do what it needs to do and will die sooner. I measured a 5 ton system the other day that only had 533 CFM’s ( or 533 basketballs of air per minute) going into the return when it should have had 2,000 CFM’s. That’s like living your life with your lips taped around a coffee stirrer straw and a clothespin on your nose. It is no wonder that the homeowner isn’t feeling comfortable and has high bills. The system can not exhale on the supply side what it isn’t inhaling on the return side. Most of the time our duct replacements will include the addition of a new return or enlarging the existing return.

Additionally ducts systems that are designed well can deliver prescribed CFM’s on a room by room basis, thus ensuring similar temperatures throughout the house and a greater sense of comfort. One of the last steps in all of our installations involves one tech measuring the air at each register with a flow hood against the design and calling up to the other tech in the attic who moves a series of manual dampers in the duct system so that each register gets to within 10% of the designed airflow. Every room in a house is different, if not in size then in the amount of windows it has and how it orientates to the sun as it passes over your home. Thus the load in each room differs. Air balancing according to engineered design addresses these differences and results in greater comfort for the occupants of the house.

Another great result of new ducting in a home is increased insulation on the ducts. Here in California most duct systems are in the attic, where temperatures regularly reach +140°. Anything that you can do to get that air to spend as little time in that environment as possible is a plus. This includes shortening duct lengths, where possible, and sealing the ducts so that no attic air is introduced into the system. Insulating those ducts to the greatest R-value possible has a large upside as well. We install R-8 insulated ducts that is encased in Mylar® and when possible bury it in blown in insulation. This protects the air that comes from your heater or A/C as it travels through the attic as much as possible.

Quality designed ducts should deliver the air evenly, quietly and with enough velocity to mix the air in your rooms. It should maximize the equipment that you put into your home. Quality designed ducts are the most important component of your heating and air conditioning system, so why wouldn’t you replace them?

Be sure to contact Redlands Plumbing, Heating & Air Conditioning for all your service and accessory needs. We provide “Service Worth Bragging About” to the Inland Empire including; Redlands, Yucaipa, Loma Linda, Beaumont, Highland, Riverside, Banning, and Rancho Cucamonga.