Thank you for your question on the model QT110LE exhaust fan/light/night light. The specification of “CFM @ 0.10, 0.125 & 0.25” refers to the static pressure that is built up inside the duct work when air is blowing through it. Almost all of our exhaust fans are rated at 0.10 static pressure. This is used to determine the length of ducting that can be placed on a fan without losing CFM. The QT110LE can handle up to 13 feet of four inch, straight, rigid duct work. You would need to reduce that distance by four feet for every elbow installed.
1 day ago