Gas dryers put out poisonous carbon monoxide and MUST be vented OUTSIDE. Venting a gas dryer into any enclosed space is NOT an option, no matter how tempting it is. Even if you think you'll always open the garage door, you don't want to risk it.

Gas has to be vented outside or carbon monoxide could leak into the home.
Electric could be vented into the garage but you'd have to deal with moisture and condensation.

You really wont have too many issues with a 12 foot run.

The maximum length depends on the type of ducting material used. Here is a chart of maximum lengths:

For 4" exhaust hoods and 4" diameter rigid heavy metal vent:

# of 90 degree turns Maximum length

0------------------------ 64 ft.

1 ------------------------ 54 ft.

2 ------------------------ 44 ft.

3 ------------------------ 35 ft.

4 ------------------------ 27 ft.

For 4" exhaust hoods and 4" diameter flexible heavy metal vent:

0------------------------ 36 ft.

1 ------------------------ 31 ft.

2 ------------------------ 27 ft.

3 ------------------------ 25 ft.

4 ------------------------ 23 ft.

Thank you so much for the information. My GC suggested venting it to the garage! I think he must have forgotten it is a gas dryer (at least I hope he had just forgotten)

Thank you so much for the information. My GC suggested venting it to the garage! I think he must have forgotten it is a gas dryer (at least I hope he had just forgotten)

Either the GC forgot or they have theirs venting into their garage and the fumes are starting to get to him.

Venting electric dryers into the garage is against code too! It has to do with the wall between the garage and home being a firewall, and no penetrations between the two are allowed. That's why new homes must have a fire resistant door rather than the old wood one with the glass pane that most of us have that is grandfathered in until we replace it.

This is very good information, I am glad I you posted this Renov8r.