For optimum performance locate it between.
How to vent bathroom exhaust fan in attic.
Either way the vent will have to go directly to the outside and installed with a vent hood cover.
Measure the vent fan.
Take a look at the installation manual for your fan brand and model.
Through the roof or an exterior gable wall.
The best exhaust fan venting is through smooth rigid ducts with taped joints and screwed to a special vent hood.
The manufacturer will give guidance on the total duct length permitted.
In general you can try venting a bath vent fan down but the combination of down direction elbows and total run length may mean that it s ineffective.
You should never exhaust the bathroom fan directly into the attic.
Options for venting a bathroom exhaust fan include best to worst.
Use an extra long 3 8 inch diameter spade bit to bore a reference hole through the ceiling and into the attic.
Your attic is not a temperature controlled environment is never the same temperature as your living space and generally closer to the temperature outside.
Although this isn t always possible in attic crawl spaces you should always insulate the duct to prevent condensation problems.
When venting a bathroom exhaust fan make sure to vent the air to the outside rather than into your attic where it can cause mold and mildew to form.
The correct way to vent a bathroom fan through an attic is to terminate the vent either to the roof or to the gable wall.
Duct already wrapped in insulation at home centers.