When to Test
Duct testing is strongly recommended when a new heating and/or air conditioning unit is being installed. If the existing duct system is leaky and inefficient before the new unit is installed, it will remain in that condition even after the new unit is installed.
Testing is also recommended when a diagnostic tune-up is performed on a heating and air conditioning unit. A diagnostic tune-up can improve the operating efficiency of the heating or air conditioning unit itself, but the overall efficiency will still be less than adequate if the duct system is not in good condition.
A duct test is necessary to determine leaks, needed repairs, and/or renovations. Duct testing can be performed at any time, despite whether or not new energy efficiency equipment is being installed.
Duct Testing and Sealing
Did you know that up to 20% of the heated or cooled air in your home may be wasted by leaky ducts? That means you could be paying to heat an attic crawl space instead of your living room. Properly sealed and installed ductwork can make your heating, ventilation, and air conditioning system more efficient and your home more comfortable.
How do you know if your duct system is in good condition?
The most reliable and cost-effective way to find out is to have a duct test performed by a qualified technicians using the proper test equipment. Duct testing is the process of using calibrated mechanical equipment to measure the amount of airflow that is lost through the duct system when it is at normal operating pressure.
While some joints or seams may have only small leaks, other sections may be completely disconnected. Duct testing can indicate the relative leakiness of the ducts and help determine whether the duct system should be sealed, repaired, or renovated.
Duct Sealing
Duct sealing involves following established procedures and applying approved materials to seal air leaks. Locations where sealing is typically performed include the supply and return plenums (which are connected to the furnace cabinet), starting collars (where ducts are connected to the plenums), fittings in the duct runs (Ys, where ducts branch off, and elbows), splices within the duct run, and terminations where the ducts connect to the supply registers.
The most important leakage areas are in the supply and return plenums, because these areas are closest to the air handler and under the highest pressures when the system is operating. All sealing must be performed according to specific building codes and any related energy efficiency program standards. Marshalls technicians are familiar with, and follow the standards and codes for duct sealing.