Kitchen/range fan--required?

[MikeT]

I had a great visit from inspectors this week.  Didn't pass the electrical, but there are only a few things to fix.  But I did pass the rough plumbing.  And since the same inspector who approves the plumbing also does the mechanical and structural (framing), he walked around and noted a few things to take care of before those inspection.

As he was leaving, he said I needed a kitchen fan/vent hood, minimum 150 cfm.  That comment caught me off guard.  I hadn't even thought about a kitchen fan.

Is this a new code requirement?  It could be a local deal, but before I ask, I thought I would was ask you folks.

Also, irrespective of the potential requirement, do you think it is a good idea?  Of course the fan manufacturers all tell of why this is so important (airborne grease particulates, etc)....

Thanks,
mt

[n74tg]

I think it is a good idea, but for a different reason.  Cooking creates lots of moisture (think a pan of boiling water).  If your house is built tight, that moisture needs to exit somehow.  If it doesn't, the raising of the relative humidity to above 55% provides the environment necessary for your mold spores to start growing.  Every house in America has mold spores.   Below 55% they don't grow.  So yes, I would ventilate purely to try to reduce the humidity.  The same situation exists in your bathroom with all that steam from your shower condensing on your mirror (and walls, and everything else).  Ventilate there too.

Now, if you live where the outside relative humidity goes/stays above 55% (all over the south) then you're pretty much screwed because whatever you vent out somewhere will infiltrate in from somewhere else.  Still, if your venting 80% humidity air from the kitchen and replacing it with 55% humidity air from outside, at least it's an improvement.

Did the inspector say anything about bathroom vents?

So much for short answers.

[MikeT]

I have a fan for each bath.  He was fine with my smallish fan (70 cfm) because I have operable windows.

[ScottA]

I'd put one in for all the same reasons n74tg gave.

[MountainDon]

Depending on what code version your locale is uses you would either need a vent hood that vents to the exterior, or an approved recirculating, filtered non venting model, if they approve the use of a non vented model.

I believe the exterior venting style is superior, but is frequently not used because there is more work and expense.

[fishing_guy]

We used the non-venting, in combination with an over the stove Microwave.  $250 for the combo microwave/stove hood.  Works like a charm.  But then again, we cook outdoors on our grill as much as possible.

[MikeT]

I heard back from my inspector.  He said I am working off the 2005 code requirements which list a 100 cfm fan as the minimum.

So if I have a 180 fan that I vent to the exterior (either straight up or out the wall), that should suffice, right?  I ordered a bath/kitchen fan manufactured by Broan. 

mt

[frazoo]

Over the years I have replaced a lot of cabinets in kitchens with both vented to outside and non-vented units.  There is a big difference between the walls and cabinetry condition with regard to the two different units.  I always recommend the vented to outside units, Like MountainDon stated, they give far superior results.

good luck,

frazoo