The warm moist air inside the vent tends to.
Outside dryer vent on roof.
Vent dryers outside venting the dryer outside in cold weather wastes a lot of heat.
Considering that back pressure higher than 6 wci is generally recognized as inefficient you can see that venting through the roof with non dryer specific vents is immediately problematic.
Dryerjacks are the first roof vents designed to meet the more stringent venting requirements of dryer exhaust systems.
You can now replace the outer vent cover.
The problem with attics the attic is usually colder than the rest of the house during the winter and that can create a problem for a dryer vent.
Run your dryer until no debris comes out of the outer vent making sure that the air flow is not restricted.
But we don t recommend it for two reasons.
Vent a dryer through the roof only as a last resort.
Cleaning lint buildup from roof vents is difficult and nesting birds and squirrels often find roof vent caps irresistible.
To make the dyer more efficient you can buy an inexpensive heat diverter and install it in the exhaust duct of electric dryers only not gas dryers you ll save about 50 worth of heat per load in the winter.
Once you have done this turn off your dryer.