Roof-vent-for-gas-dryer, for dryer efficiency and safety, the shortest and straightest ducting route is always best. every turn increases friction loss (unless you use non-restrictive elbows).air velocity reduction from friction loss promotes lint build up and makes the dryer work harder to completely dry each load. length of run also reduces efficiency.. How to install rooftop dryer vents. dryer vents direct warm, moist, lint-laden air outside, which protects your home from the damage that damp air can cause and prevents a fire hazard from lint ..., if you're having a home built, try to have your builder terminate the dryer duct at a location that makes sense. in my humble opinion, dryer vent terminals should be accessible from the ground.if you already have a home with a dryer that terminates at the roof, be sure to have the terminal cleaned on a regular basis, and consider having the terminal replaced with a dryerjack terminal.