Do you want to learn if range hoods need to be vented to the exterior?
Range hoods play an important part in keeping a healthy home, and remove smoke, odors, and cooking fumes.
In this guide, I will go over...
- Range hood venting requirements
- My preference in ducted vs ductless
- State building codes on venting
Let's get started with this guide!
Do Range Hoods Need To Vent To Exterior?
For most new homes around the country, range hoods are required to be vented to the outdoors. This common building code is important to prevent builders, contractors, and homeowners from venting a range hood improperly.
As a home inspector, I have seen numerous exhaust ducts that get foolishly ducted to an attic, crawl space, or a even a wall cavity. If a range hood gets ducted to an attic, all of that moisture will stick to the roof sheathing, trusses, and any other surface.
As a result of venting into an attic, mold can form, and may even release harmful spores that get circulated throughout the entire home.
Besides the mold issue, most homes aren't perfectly sealed from the attic, which means that all of those cooking fumes can get recirculated back into the home.
Government authorities want to avoid this problem which is why venting to the exterior is in the building code. However, this doesn't mean that installing a recirculating range hood (ductless) isn't allowed. In fact, most states allow ductless range hoods as part of an exception to the 'venting outdoors' rule.
An easy way to check that the range hood doesn't have improper ventilation is to turn the range hood on, and to physically check the air flow on the outside. Depending on the location of the vent hood, you may need a ladder. The air flow should feel strong.
Read Also: What Are The Best 30-Inch Range Hoods?
Building Code Example
Here is an example from the state of Texas which is uses very similar language to many U.S. states including the exception for ductless. The term 'natural ventilation' refers to open windows and things like that.
TEXAS Building code example
Range hoods shall discharge to the outdoors through a duct. 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 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.
Recirculating Range Hoods
Many of the homes that I inspect have recirculating range hoods, especially condos and older homes.
These hoods do not have a vent, and a metal mesh filter traps grease while the air is recirculated back into the room. Ventless range hoods also have an additional layer of filtration which is a carbon layer that captures smoke and odors.
Read Also: How To Paint An Old Range Hood?
Vented Range Hoods Are Superior
Vented range hoods are always better than ductless range hoods. If my clients ask for my opinion, then I always recommend installing a ducted range hood.
A ducted range hood just works better at removing grease, cooking fumes, hot air, and smells. In fact, a recirculating hood simply cannot remove hot cooking gases.
It has no method of cooling down these gases after it goes through the filter, so it just gets sent back into the kitchen. Of course, you could open a window or provide other means of ventilation to supplement a recirculating range hood.
But this is just my recommendation, and ventless range hoods are installed in numerous homes.
In fact, if you look at the product descriptions of almost all range hoods, virtually all of them can be converted to a ductless installation. Recirculating range hoods just require the addition of the charcoal filter layer in addition to a aluminum mesh filter.
Read Also: What Are The Best Downdraft Range Hoods?
To summarize, most U.S. states require range hoods to vent to the outdoors. You can't vent into an attic, crawlspace, wall cavity, or anywhere that isn't to the exterior.
But for your own health, homeowners should avoid improperly ducted range hoods. If improperly vented, range hoods can release harmful particulates into the home's interior air, and may cause health problems.
Most U.S. states do allow ventless or recirculating range hoods.
Usually, the only additional thing you will need is the right filter. Recirculating range hoods require an aluminum mesh filter that also has a layer of activated carbon. The carbon captures smoke, fumes, and odors while the mesh filter captures grease.