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Heating, Venilation & Air Conditioning

Duct Leakage Systems

Builders will soon need to get up to speed on duct testing, since recent code changes will require that all residential duct systems except those that are located entirely within a home thermal envelope will need to be tested for leakage. If some ducts are outside of the thermal envelope, the 2009 IRC will require duct tightness to be verified by either a rough-in test or a post-construction test. Either test requires all register boots to be taped or otherwise sealed during the test. The threshold for the rough-in test is total duct system leakage of 6 cfm per 100 square feet of conditioned floor area (when tested at 25 Pascals). If the air handler is not installed, the total leakage must be less than or equal to 4 cfm per 100 square feet of conditioned floor area. The threshold for the post-construction test is duct system leakage to outdoors of 8 cubic feet per minute (cfm) per 100 square feet of conditioned floor area when tested at 25 Pascals. Alternatively, total duct system leakage must be less than or equal to 12 cfm per 100 square feet of conditioned floor area.

Energy auditors have developed several methods for testing duct tightness. These methods vary from fast and dirty to time-consuming and accurate. Builders interested in tight duct systems should familiarize themselves with the range of available duct testing options: (1) Using only a blower door, (2) Using a blower door and a pressure pan, (3) Using a Duct Blaster, (4) Using a Duct Blaster and a blower door; and (5) Using a theatrical fog machine.

Most green builders already know their duct basics: (1) Duct leaks are very common; in many homes, duct leaks are responsible for significant energy losses, (2) For ducts located in an unconditioned attic, any leaks in the supply system tend to depressurize a house, while return-system leaks tend to pressurize a house. Either condition can cause problems, (3) Duct leaks outside of a home thermal envelope waste more energy than duct leaks inside a home thermal envelope, (3) Even if ducts are located inside of a home thermal envelope, duct leaks can still connect to the outdoors, and (4) It is much easier to seal duct seams during new construction than in an existing house.

Kitchen Hood Grease Duct Leakage Testing is performed as a service to provide proof that the grease duct systems installed on a kitchen hood system has no leaks. We use only professional calibrated equipment to perform these tests to ensure the validity of these tests. Kitchen Hood Exhaust and Outside Air Ventilation Systems Balancing is performed as a service to balance the exhaust fans and outside air fans (that introduce unconditioned outside air into the building) so to bring your system into balance". An unbalanced condition can cause a Negative Pressure condition in a building which can result in all or part of the following conditions: (1) Condensation dripping from grilles or diffusers, (2) Hot/Cold spots in the dining area, (3) Hot Cook line, (3) Draft of hot, humid air incoming into building creating an extra load for the Air Conditioning systems, (4) Angry customers, and (5) High Energy bills.