Range vent into attic

I understand the rule of thumb is to vent to the outside. However, I came across a vent system from the range to the attic space above garage. At the termination point in the attic is a box with a filter and grill. Has anyone seen anything similiar? Is this acceptable? Any code issues?

San Antonio, TX




It should not terminate in the attic. Period. You can’t fix stupid.

What Joe said.

M1503.1 General. Range hoods shall discharge to the outdoors through a single-wall duct. The duct serving the hood shall have a smooth interior surface, shall be air tight and shall be equipped with a backdraft damper.** Ducts serving range hoods shall not terminate in an attic **or crawl space or areas inside the building. **

Exception:** Where installed in accordance with the manufacturer’s installation instructions, and where mechanical or natural ventilation is otherwise provided, listed and labeled ductless range hoods shall not be required to discharge to the outdoors.

Thanks for the information…

Ahhh… BUT

Is the GARAGE ATTIC considered “inside the building”???

One has to assume the garage is attached.

Other questions come to mind, such as “FireWall”, “FireRated Damper”, etc…

just call the fire department now…only a matter of time…

1 Like

“Ducts serving range hoods shall not terminate in an attic or…”

“Shall not terminate in an attic” stands alone, there are no "if"s, "but"s "except"s, "maybe"s or "sometime"s after that other than for listed ductless hoods.

No other questions need be asked/answered to determine that it is improper to vent the range hood into the attic.

I agree with Jonas.
First we do not have all the facts. Just one picture.

International Mechanical Code (IMC) 2009. Chapter 5 Section 505.1-exception 1.
Also section 501.2 Exhaust Discharge. Exception 1. Whole house ventilation-type attic vents—

Jonas is right. There are more questions. This system may be allowed.

When was this described as a “Whole house ventilation-type attic vent”? The question was in reference to a vent for a range.

Besides, you are referencing a general requirement. The specific code section for Domestic Kitchen Exhaust Systems is 505.1. Specific requirements always take precedence over general sections.

Also, assuming that this is a detached dwelling or townhouse, the applicable code would be the IRC not the IMC (though neither code allows venting to the attic, but you might as well reference the correct applicable code).

Lastly, and most important for the Texas inspector who posted the original question is what the TREC SOP requires of him

If that thing he photographed is attached to a range vent, as he described in his posted question, our Texas inspector needs to report it as deficient.

Mr Evans,

Not hear to argue with you.

As Inspector’s we will start to see more ductless range hood exhaust’s.

The Purpose of the International Building Codes is for Health, Safety and Welfare of people in dwellings. The 2009 Building Code is addressing the fact that “where installed in accordance with manufacturer installation instructions, and where mechanical or natural ventilation is otherwise provided, listed and labeled ductless range hoods shall not be required to discharge to the outdoors”.

This all has to do with “green energy” and Indoor air quality. Internachi IAC2, US Dept of Energy, HVAC Manufacture’s, ASHRAE, American Lung Association and on and on.

The new range hood system will have not just one fan, but 3 or 4 fans, the grease from cooking will be filtered out of the air, the moisture and heat will go thru HRV’s and ERV’s-Heat and Energy Recovery systems.

Your Texas inspector questions that he asked where very clear to me. Really does not matter to me what State he is from, he is an InterNachi member.

SOP’s? The Inspector asked question’s. Pardon me, I just thought it might be a learning thing. “Has anyone seen anything similiar?” “Is this acceptable?” "Any code issue’s?

I still have questions as to what type system and manufacturer. Who knows, there could be required fire damper’s for the system. There are question’s.

Again, you will see these type systems going forward. They do need to be tested and installed per manufacturer specifications. The new 2009 Building Code recognizes that fact.

The InterNachi IAC2 training and certification is free to all members. It’s the future-“Air Quality”.

Ductless vent hoods have been around as long as I can remember, yes there will be new twists on them, but recirculating range hoods are not new stuff. Of course, a ductless system would find it quite challenging to send the exhaust air from the kitchen into the attic above the garage without the use of ducts now wouldn’t it???

And these ultra modern, high efficiency, UL listed, range hood vents of which you speak are going to terminate inside the attic, inside of site-built, wooden boxes with HVAC return grills screwed onto the front of them. :roll:

So in direct answer to our inspector’s questions (assuming his basic premise that this is part of the range vent is correct):

  • No one has ever seen this
  • No it’s not acceptable (actually you should refer to it as a defect, as TREC does - we don’t determine acceptability)
  • Yes there are code issues with whichever code you choose to apply to the situation (even though IBC does not apply)

That is unless there’s a hidden UL listing sticker with accompanying installation instructions that are consistent with what we see hidden somewhere on that wooden box. LOL

No more needs to be said.

Two separate and distinct questions.

Is it acceptable? No. There is never a legitimate reason to intentionally introduce moisture to attic space.

Any code issues? Who cares?

Yes we are not code inspectors.
Would it be better if he explains the 2 entries lines and there terminations to the client in his report?
What each one is for and where it goes.
The narrative will help the client understand what is going on.
If they both terminate in the box, there is a conflict and must be looked into by a professional.
Ether way thew exhaust must continue out the attic or be vented outside…