Range hoods can vent outside, recirculate air back into your kitchen, or use a hybrid approach—the choice depends on your home's structure and local building codes.
Not every range hood exhausts to the outdoors. Many kitchens use recirculating hoods that filter grease and odors from the air and push it back into the room. Others use ducted hoods that run ductwork through walls or ceilings to an exterior wall or roof. Some homes use both types in different locations. Building codes in your area may require outside venting in new construction or major renovations, but existing kitchens often have more flexibility. The best choice for your kitchen depends on your home's layout, your budget, and what your local building department allows.
Key Takeaways
- Ducted range hoods that vent outside remove smoke, steam, and odors from your home entirely, but require ductwork running to an exterior wall or roof.
- Recirculating hoods filter air and return it to the kitchen without ductwork, making them easier to install but less effective at removing moisture and heat.
- Local building codes may require outside venting in new kitchens or renovations, so check with your building department before choosing a hood type.
- Ducted hoods cost more to install but perform better; recirculating hoods cost less upfront but need frequent filter changes and do not remove humidity.
How Ducted Hoods Vent Outside
A ducted range hood pulls air from above your cooktop and pushes it through metal ductwork to the outside of your home. The duct typically exits through a wall or the roof, usually within 10 to 15 feet of the hood itself. Longer ducts lose suction power, so installers try to keep the run short and as straight as possible. The duct should slope slightly downward toward the outside to prevent grease and condensation from dripping back into your kitchen.
Ducted hoods remove heat, moisture, and cooking odors completely from your home. This is especially important in humid climates or homes with poor air circulation, because recirculating hoods leave moisture behind. If you cook frequently or use high heat, a ducted hood is the stronger choice. The trade-off is cost and installation complexity—you may need to cut through walls, run ductwork, and install an exterior vent cap. If your kitchen is far from an outside wall, the ductwork becomes expensive and harder to hide.
How Recirculating Hoods Work Without Outside Venting
A recirculating hood has a fan and one or more filters inside the unit. Air passes through a grease filter, then through a charcoal or carbon filter that traps odors, and the cleaned air blows back down into your kitchen. No ductwork is needed, so installation is straightforward—you just mount the hood and plug it in. Recirculating hoods work in any kitchen layout, even if there is no straightforward path to an outside wall.
The downside is that recirculating hoods do not remove moisture or heat from your home. If you boil water or steam vegetables regularly, that humidity stays in your kitchen and can eventually damage cabinets and drywall. Recirculating hoods also need more maintenance—charcoal filters typically last three to six months before they stop absorbing odors and need replacement. Grease filters need cleaning every month or two. Because they are less powerful at removing smoke and steam, recirculating hoods work best in kitchens where you do light to moderate cooking.
What Building Codes Require in Your Area
Building codes vary by state, county, and city. Many jurisdictions require outside venting for new kitchens or major renovations, but allow recirculating hoods in existing kitchens that are not being remodeled. Some areas have no requirement at all. A few places require outside venting only if the kitchen has a gas cooktop, because gas cooking produces more moisture and carbon dioxide than electric cooking.
Before you buy or install a range hood, contact your local building department or code office and ask what is required for your address. They can tell you whether you need outside venting, whether your ductwork route is allowed, and whether you need a permit. If you are renting, check your lease or ask your landlord—some rental agreements forbid ducting through walls or roofs. Getting this answer first saves you from buying the wrong hood or installing it incorrectly.
Comparing Cost and Installation Effort
Recirculating hoods are cheaper to buy and install. A basic recirculating hood costs $150 to $400 and takes an hour to mount and plug in. You do not need a contractor. Ducted hoods start around $300 to $500 for the hood itself, but ductwork, venting materials, and labor can add $500 to $2,000 or more depending on how far the duct has to run and whether you need to cut through walls or the roof.
If your kitchen is already close to an exterior wall and you are comfortable with basic installation, ducted venting may not be much more expensive. If your cooktop is in the center of your kitchen or far from outside walls, recirculating becomes the practical choice unless you are willing to pay for extensive ductwork. Consider also the long-term cost of filters—recirculating hoods need charcoal filters every few months, while ducted hoods need only occasional grease filter cleaning.
Hybrid and Convertible Hood Options
Some range hoods are convertible, meaning they can work either ducted or recirculating depending on how you install them. You buy the hood and then choose whether to run ductwork outside or install a recirculating filter kit inside. This flexibility is useful if you are unsure about your final setup or if you might move the hood later. Convertible hoods cost slightly more than single-mode hoods, but they give you options.
A few kitchens use two hoods—a ducted hood over the main cooktop and a recirculating hood or downdraft system over an island or secondary cooking surface. This approach works when one location has straightforward access to outside venting and another does not. It is more expensive overall but lets you get the best performance where you cook most often.
Common Mistakes When Choosing a Hood Type
The most common mistake is buying a recirculating hood when you need ducted venting. If you cook with steam, boil water often, or live in a humid climate, a recirculating hood will not remove enough moisture and your kitchen will feel damp. Charcoal filters also wear out faster in high-moisture kitchens, making the hood less effective and more expensive to maintain.
Another mistake is running ductwork that is too long or too crooked. Every bend and every extra foot of duct reduces suction power. If your duct run is longer than 25 feet or has more than four bends, the hood will not pull smoke and steam as well as it should. A contractor can help you plan the shortest, straightest route, or you may need to accept a recirculating hood if outside venting is not practical.
A third mistake is not checking local codes before installation. Some jurisdictions require permits for range hood installation, and installing without a permit can cause problems when you sell your home or file an insurance claim. A few minutes on the phone with your building department prevents expensive mistakes later.
Frequently Asked Questions
Can I use a recirculating hood if I have a gas cooktop?
Yes, but it is not ideal. Gas cooking produces more moisture and carbon dioxide than electric cooking, so a recirculating hood will not remove as much of the byproducts. If you use gas, a ducted hood is the better choice. Some building codes require outside venting specifically for gas cooktops, so check your local rules first.
How often do I need to replace charcoal filters in a recirculating hood?
Most charcoal filters last three to six months with regular cooking. If you cook daily or use high heat often, they may wear out faster. You will know they need replacement when cooking odors linger in your kitchen even after the hood runs. Grease filters should be cleaned monthly or when they look visibly dirty.
What happens if I vent my range hood into the attic instead of outside?
Do not do this. Venting into the attic traps moisture, grease, and heat in a space that is not designed for it. This causes mold, rots wood framing, and damages insulation. It also violates building codes in most places. Always vent to the outside air through a proper duct and exterior vent cap.
Can I install a ducted hood myself, or do I need a contractor?
straightforward installations—mounting the hood and running short ductwork to a nearby exterior wall—are possible for handy homeowners. Cutting through walls, running ductwork through multiple rooms, or venting through the roof usually requires a contractor and a permit. If you are unsure, hire a professional to avoid damaging your home or violating codes.
Does a range hood have to be directly above the cooktop?
Most hoods are mounted directly above the cooktop for best performance, but some kitchens use island hoods, wall-mounted hoods, or downdraft systems in different locations. The hood should be positioned to capture smoke and steam as they rise, so placement matters. Consult the hood's manual and your local codes for minimum clearance and positioning requirements.