When doing a Total Duct Leakage test, should you open the attic hatch?
Duct leakage standards and protocols say that if ducts run through unconditioned spaces, those unconditioned spaces should be opened to the outside. One way of opening those spaces to the outside would be to open an attic hatch to the home and also open a window between the home and outside. The goal is to prevent the duct leaks from changing the pressure in the spaces containing ducts.