Whirlybirds on a manufactured home - December 16th 2009
Q. We live in a doublewide manufactured home that has two whirly bird vents on the roof that were installed by the previous owner. The whirlybirds do not require much of a wind to start them going but there cannot be much more than a foot or two between the roof and ceiling since it is a low pitch metal roof. The fans make a lot of noise and in colder weather; we notice quite a substantial draft down the hallway. The bedrooms at the rear of the home are also quite chilly, also perhaps part of a draft problem we have. With such a small space between the outer roof and the ceiling, would you think that the fans are of much benefit in summer or winter should we remove them?
A. My suggestion would be to cover the turbine vent units with a heavy-duty plastic bag for the fall and winter months. I seldom recommend whirlybird vents on a modular home because by and large, the ceiling is not draft proofed and can become drafty. A basic rule of thumb on a modular homes built to factory specs is that if extra venting is required, it would have been put there at the time it was built. Try covering the vents instead of removing them at this time since it will be less costly.
Note: If vents were installed over openings where original roof vents located I suggest you replace the turbines with static mushroom vents.