A range hood can sound powerful and still let smoke roll into the kitchen. Airflow depends on more than the number printed on the box: the filter has to be clean, the blower has to move air through the installed duct or recirculation path, and the hood has to capture the plume rising from the cooktop. Before shopping for a larger motor, identify whether your hood actually vents outdoors and whether its existing air path is restricted.
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If you need the short version, try these steps first.
- Turn the burners off and let the cooking area cool before inspecting the hood.
- Identify the hood model and whether it is installed as ducted or recirculating.
- Remove and clean a reusable grease filter or replace a disposable/charcoal filter only as the manufacturer directs.
Check these safety points before you start.
- Turn cooking equipment off and let surfaces cool before handling filters or reaching under a range hood.
- Do not vent a range hood into an attic, wall cavity, crawlspace, garage, or other concealed area, and do not substitute plastic or dryer-style duct where the hood manufacturer prohibits it.
- Electrical repairs, concealed duct changes, roof penetrations, and high-capacity make-up-air design should be handled under applicable local code by qualified professionals.
First find out whether the hood exhausts outdoors or recirculates
Ducted hoods send cooking air outside. Recirculating or non-ducted hoods pass air through grease and usually charcoal filters, then return it to the room. A recirculating hood can reduce grease and odor but cannot remove cooking moisture outdoors the way a ducted system does. Over-the-range microwaves may also be configured either way.
Check the model number, installation manual, cabinet or wall duct path, and exterior cap before judging performance. If there is no outdoor duct, seeing steam remain in the kitchen does not necessarily mean the blower is broken.
- Turn the burners off and let the cooking area cool before inspecting the hood.
- Identify the hood model and whether it is installed as ducted or recirculating.
- Remove and clean a reusable grease filter or replace a disposable/charcoal filter only as the manufacturer directs.
- With the hood running and cooking off, check whether the exterior damper opens if the outdoor termination is safely accessible from ground level.
- After maintenance, test capture during normal cooking by using a rear burner first and turning the hood on before cooking begins.
Grease-loaded filters are a common airflow restriction
Broan-NuTone notes that grease and debris buildup restricts airflow and reduces ventilation performance. Aluminum mesh and baffle filters are often washable, while charcoal filters used for recirculation are generally replaced rather than washed. The exact interval depends on the model and cooking habits.
Do not put a filter in a dishwasher unless its instructions allow it, and do not operate the hood without the required grease filter just to make the suction feel stronger. The filter protects the blower and duct from grease accumulation.
A strong blower cannot overcome a poor duct path indefinitely
For ducted systems, crushed flexible material, excessive elbows, a stuck backdraft damper, grease buildup, or ductwork smaller than the hood manufacturer requires can reduce delivered airflow. Broan-NuTone specifically warns that reducing duct size restricts hood performance and advises using the duct dimensions specified for the model.
Do not substitute dryer duct, plastic duct, or an attic termination for a proper kitchen exhaust path. If the duct is hidden in walls or ceilings, or if changing it affects fire-rated construction, cabinets, roof penetrations, or local code, have the installation evaluated by a qualified contractor.
Capture area and make-up air matter when you are choosing a replacement
A hood should cover the cooktop well enough to catch the rising plume. Broan-NuTone recommends choosing a hood at least as wide as the cooking surface, and front-burner smoke is generally harder to capture when the hood is shallow or mounted high. More CFM can help only if the duct and installation can support it.
Very high-capacity exhaust systems can also trigger local make-up-air requirements, and rules vary by jurisdiction. Before buying a much larger hood, check the current local code, the cooking-appliance requirements, duct size, hood width and depth, noise rating, filter type, and whether the home can provide replacement air safely.
Before you call it done
- The hood was identified as ducted or recirculating before outdoor moisture removal was expected from it.
- The correct grease and charcoal filters were cleaned or replaced according to the model instructions.
- The exterior damper and visible duct path were checked without climbing or dismantling hidden construction.
- Duct size and material were compared with the hood manufacturer's installation requirements.
- A replacement hood is being sized for cooktop coverage, duct capability, noise, and local make-up-air rules instead of CFM alone.