Kitchen Exhaust Hood

About Your Kitchen Exhaust Hood

Most kitchens I encounter on home inspections in San Diego and Temecula Valley have a range hood of one type or another installed. Some are integrated into a combination microwave/hood, and some are stand-alone exhaust hoods.

This is a combination microwave/hood. These are very popular.

This is a combination microwave/hood. These are very popular.

 

Types of Exhaust Hoods

Many exhaust hoods merely recirculate the air by pulling it through the filter  and then just blowingit back into the room. I don’t know how this can possibly remove the odors and moisture created by the cooking process.

This is an example of a recirculating exhaust. Notice that there is no ducting.

This is an example of a recirculating exhaust. Notice that there is no ducting.

For the exhaust hood to be truly effective, it needs to exhaust this dirty air to the exterior of the home. If the hood is on an exterior wall, the exhaust duct can be installed to go through the sidewall. This makes for a very short run of ducting. If the hood is installed on and interior wall, then the duct can be installed to exhaust the dirty air through the roof. It can also be run through a soffit to the exterior wall. The route you take should be discussed with your HVAC contractor. He will give you multiple options and the cost involved for each option.

This duct exhaust to the outside. They however used an inappropriate cloth duct tape. 

This duct exhaust to the outside. They however used an inappropriate cloth duct tape. 

This is the exhaust duct going through the roof.

This is the exhaust duct going through the roof.

Many times I have found that the duct didn't make it through the roof.

Many times I have found that the duct didn't make it through the roof.

 

Use The Proper Duct Material

Most manufacturers recommend using a smooth rigid 6” duct for your exhaust. Flexible, or corrugated duct, is not approved for use by any manufacturer that I am aware of. The use of a flexible duct is just inviting a fire hazard from a build-up of grease and dirt.

This looks like a handyman install. Flexible duct is not recommended by most manufacturers.

This looks like a handyman install. Flexible duct is not recommended by most manufacturers.

This is typical of most manufacturers.

This is typical of most manufacturers.

When installing the duct the joints should be sealed with the appropriate foil tape. Cloth backed duct tape is not recommended for exhaust ducts and in attic spaces. The heat associated with these areas causes the duct tape to lose its adhesive capabilities.

This is what happens to duct tape in the attic.

This is what happens to duct tape in the attic.

 

Who Should Install Your Exhaust Hood?

The installation of an exhaust hood can be done by a handy homeowner with help from YouTube and other online resources, however, I recommend that you use a licensed professional so that you know it is done correctly.

A job well done. Notice the foil tape on the joint, and the cover on the outlet.

A job well done. Notice the foil tape on the joint, and the cover on the outlet.

About the author: Frank Rotte is the Owner of Certified Inspection Services, LLC in Bonsall, CA. Comments are always welcome! Please visit us on Facebook at https://www.facebook.com/homeinspectionsandiego/