A duct leakage tester is a diagnostic tool designed to measure the airtightness of forced air heating, ventilating and air-conditioning (HVAC) ductwork. A duct leakage tester consists of a calibrated fan for measuring an air flow rate and a pressure sensing device to measure the pressure created by the fan flow. The combination of pressure and fan flow measurements is used to determine the ductwork airtightness. The airtightness of ductwork is useful knowledge when trying to improve energy conservation.
And when you’re testing for airtightness, each cubic foot of air that leaks out of the duct system must be made up by a cubic foot of air blown in by the fan. So once you’ve measured the amount of air moving through the fan, you’ve quantified the duct leakage at the test pressure.
For duct leakage testing, the standard pressure used is 25 Pascals, which is close to the operating pressure of a typical duct system. This means that when we measure, for example, 120 cubic feet per minute of duct leakage at 25 Pascals (written as 120 cfm25), that number is a pretty good estimate of how much air leaks out of the duct system while operating.
Duct repairs become necessary when your home or office building begins to have cold spots during winter months or hot spots during summer months. It could be an indication that not enough heated or cool air is reaching certain sections of the ductwork. This could be because of a blocked or leaky duct. If the heating and air conditioning system feels as if it’s slowing down, becoming less effective and ends up being unable to cool or heat a space that it once did easily, this could mean that there is a duct problem that needs to be addressed with repairs.
It’s definitely good to call in a professional to repair those duct systems. Common methods for sealing ducts involved commercial HVAC tape and mastic. But if the ducts are really old, leaky and lack adequate insulation, then the best option may be to upgrade to new, insulated flex ducts.
Once you know that the air you pay to heat and cool is not being lost through bad ductwork, “out of sight, out of mind” will have real meaning.
There are two kinds of leaks, benign and malignant. The malignant leaks are the ones that need immediate attention. They’re the ones that send conditioned air into unconditioned spaces, or suck the unconditioned air into the system. Benign leaks are the ones leaking inside the conditioned space; they don’t exact an energy penalty.
These two kinds of duct leakage, of course, require two different types of tests. The malignant leaks occur in ducts that are outside the conditioned space, or outside of the building envelope, in building science jargon, so the most important test is called an “outside leakage test.” The other test is called the “total leakage test.”
If you would like our help in conducting the ideal duct leakage test for your home, we at Climate Partners would be more than happy to assist you. We give you premium service and help you save on cost. If you’re in New Haven and Fairfield Counties, CT, or surrounding areas, don’t hesitate to call 203-457-8581 or visit our contact page.
I called in the evening about an under-performing central AC unit and Casey's was super responsive and helpful! John, my tech, came out and had the issue diagnosed and resolved within an hour!
Great team at Climate Partners. We were very happy with the whole process and would recommend them to anyone.
Technician was on time and provided excellent service and information. Very happy to be a Climate Partners club member!