I had a contractor install a hood vent. He ran a foil pipe up towards the roof and tie it @ 6 in below the turbine vent (whirley birds). Is this adequate for all the fumes to escape out? Is this ok? He told me to run it out through the roof it would cost more money.
- It is explicitly not to code to exhaust into the attic or to use foil pipe
- It's a bad idea anyway because it puts smoke, grease and warm humid air into your attic which can cause mold growth
M1501.1 Outdoor discharge.
The air removed by every mechanical exhaust system shall be discharged to the outdoors in accordance with Section M1506.3. Air shall not be exhausted into an attic, soffit, ridge vent or crawl space.
Foil pipe is also not allowed:
M1503.2 Duct material.
Ducts serving range hoods shall be constructed of galvanized steel, stainless steel or copper.
I'd also say aside from the material, foil pipes don't meed the requirement of having a "smooth interior surface":
SECTION M1503 RANGE HOODS
Range hoods shall discharge to the outdoors through a duct. The duct serving the hood shall have a smooth interior surface, shall be air tight, shall be equipped with a back-draft damper and shall be independent of all other exhaust systems. Ducts serving range hoods shall not terminate in an attic or crawl space or areas inside the building.
Also note that range hoods are very explicitly not allowed to exhaust into an attic, though there is an exception for hoods that are specifically built to exhaust elsewhere:
M1503.1 Exception: Where installed in accordance with the manufacturers 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 of course can vary by jurisdiction (eg: your jurisdiction may follow a different version of IRC, have their own amendments, or not follow it at all), and the final call is up to the AHJ (Authority Having Jurisdiction, aka inspector). You can likely call your local building permits department to be sure.
I don't know where you live, but something to consider is that you're dumping warm, moist air into a potentially cold zone. So some of that air can/will condense in there in winter. Since attics tend to be filled with untreated wood, that means you're creating all the necessary conditions for mold to grow. That can potentially negatively affect your home air quality.
Code or not, I'd get it vented out of the roof.