OT - oven hood venting

[justanengineer]

everyone i know that has a vented hood (and clothes dryer vent for that matter) experiences a little heat loss through the vent pipe. how would one avoid that?

Use a cap that seals decently and/or is insulated, install a buffer, ensure the pipe is properly insulated and/or taped, ensure the cap isnt installed in a way that will let it blow or hang open, and/or few other lil "tricks" that Im sure someone else knows. Theoretically youll always lose a tiny bit of heat, but you shouldnt feel a draft or temperature difference near the hood.

[mickeyf]

No one has mentioned (or I missed it) Building Codes. They generally have something to say about this, and more often than not it's "must vent to outside". I suspect there is a reason for this...

[Doozer]

A remarkably low airflow seems to work wonders. What you're trying to ventilate can't be worse than a hot air gun, so I donno about suggestions for something NASA would use for a space shuttle wind tunnel, or five times the size of my HVAC ducts. Think of your clothes dryer duct, that thing handles 3000 watts of condensing steam, so unless you've got industrial cook gear like a KFC would have, something the size of a clothes dryer duct should be, and seems to be, adequate.

Who suggested to use something like NASA?
Who suggested to use something 5x the size of an HVAC duct?
A clothes dryer definitely has a fan to blow air,
but not sure how 3000 watts of steam enters the equation.

What I do know is that the fan in your clothes dryer
is a whole lot larger than the fan in a typical range hood,
and it is powered by a lot larger motor. This is very much
why dryer vents are 4" round pipe.
Range hoods having small fans and motors need a larger
exhaust pipe because they develop less static pressure.
The 3-1/4 x 10" duct is standard on most range hoods
that I have seen. Why adapt it down smaller??
What you are saying just does not make sense.

--Doozer

[Tony Ennis]

No one has mentioned (or I missed it) Building Codes. They generally have something to say about this, and more often than not it's "must vent to outside". I suspect there is a reason for this...

The code in Louisville is that the oven hood must vent outside or be of the 'filtered' variety.