A typical forced air system can loose 15 to 30% of its nominal capacity through duct losses. Duct systems leak at fittings, joints, register boots, and other connections. When these leaks are outside the conditioned space, huge amounts of energy are lost. A typical duct test requires sealing of the register openings and pressure testing the duct system to a defined pressure (typically 25 Pascals) through a calibrated fan where leakage can be measured. Sealing leaks can as simple as coating joints with mastic to stop air leaks. TruTech Tools recommends Vent Caps or Vent Covers to seal register openings where ever possible as they install/remove faster and produce no waste. Need additional information? Give us a call. We can help!