I have a new single story home in Houston Texas and the bathroom exhaust fans are vented to the soffits. Is this within code? There are other single story homes in my subdivision where the exhaust vents are vented out the wall. The home builder is telling me it can be done eather way. I am thinking the moisture will be drawn up into the attic and create problems. Please inform me of a websight where I can verify the code for Harris County Texas. Thank You.

Houston refers to the 2000 edition of the Uniform Mechanical Code, which is not available online for review, at least that I can find.

The best venting method would be directly outside. Allowing the vented air to be restricted by the soffit material, even if there are openings in the soffit, will cause some air to be trapped in the attic. Any moisture in the vented air that gets trapped in the attic can add to the moisture to the space and may condensate if the temperature in the attic is lower than outdoors.

The condensation will add mold,mildew, and damaging water to the attic area.

You should be able to find a copy of the 2000 Uniform Mechanical Code at the library, or call the code enforcement office and speak with an inspector.

What is your definition of “vented to the soffits”? If the ducting simply ends inside at the soffit/eve, which it sounds like from your post, you could eventually have problems. Soffits have vents for air circulation to the attic, they are not made for venting bath fans, or any other type of exhaust fans. I’ve installed a number of these fans and all the instructions, and everything else I’ve read, state the fan should directly vent to the outside, for all the reasons TKRussell stated. You don’t want moisture in the attic.

Or, is your fan actually vented to the outside at the soffit with an under the eve vent, as opposed to other houses in your area that vent at the wall? These under eve vents are used when it is not practical to use a wall vent, or if you do not want to cut a hole the roof for a vent. The problem with these under eve vents is that the ducting has to bend downward at the vent connection which reduces the fan efficiency.
As TK stated, may be best to give your local code department a call…