March 2026 EnergyWiseSM Tip: In the Hood
By: Energy Efficiency Program NPPD Manager Cory Fuehrer
Have you ever gone over to a friend’s place for a fish dinner and left smelling like fried carp? If so, it could be that their kitchen exhaust hood was not working properly.
While commercial kitchens use exhaust systems that are fairly complex, exhaust hoods in most homes are relatively simple. They capture polluted air by drawing it in with a single fan and venting it outside or filtering it before recirculating the air back into the kitchen. In doing so, they reduce the amount of airborne grease, smoke and odors to help protect your walls cabinetry and ceilings. Many kitchen exhaust hoods even assist in removing excess heat or providing additional light over a cooktop or range.
Whether you are building a new home, remodeling a kitchen, replacing an old hood or are simply wanting to make the most of your current one, the following factors impact a hood’s effectiveness and efficiency while clearing the air:
Types
- Under-cabinet – Most common type. The fan is usually located in cabinetry above.
- Wall-mount/Chimney – In addition to the hood, the ducting and often the fan housing are visible. Often matched with high-performance options.
- Island/Canopy – Ducting extends down from the ceiling over a cooktop. The fan is in the ducting or mounted outside the home. This type requires higher fan capacity due to lack of a wall for smoke containment.
- Downdraft – Unit is built-in behind or next to the cooktop. This type also requires higher fan capacity due to fumes being drawn downward.
- Built into microwave – With an overhead microwave, this type is a popular space saver. However, fan capacity is limited.
Ducted, Ductless and Convertible
Ducted range hoods vent externally, which means they draw kitchen air out of the house through ductwork in the wall, ceiling or floor. External venting is available in all types of range hoods but is particularly common in wall-mount, island, canopy and downdraft types. Ducted range hoods are often labeled as “vented” in product names and specifications. If reducing heat in the kitchen or removing odors is a significant concern, a ducted range hood is recommended.
Ductless range hoods filter kitchen air then recirculates it back into the kitchen. Under-cabinet and microwave hoods are most commonly ductless. Ductless range hoods are most common in the under-cabinet and built-in microwave styles. Product specifications will most likely say “recirculation”, indicating it is ductless.
As the name implies, a convertible range hood can vent externally or recirculate the kitchen air. Under-cabinet and canopy hoods are the most likely types to be convertible, but keep in mind that kits are available for non-convertible models that make them convertible.
Rated CFM
The Cubic Feet per Minute (CFM or cfm) rating is a measurement of fan capacity. Hoods over electric ranges or cooktops should have a minimum capacity of 100 CFM per linear foot of appliance. Fan capacity for gas appliances should be a minimum of 1 CFM per 100 British Thermal Units (BTUs) that the stove or cooktop is rated at. (e.g., a 40,000 BTU stove needs 400+ CFM). Note that residential building codes in the state of Nebraska require installation of a makeup air units for kitchen exhaust systems capable of moving 400 CFM or more.
Width and Mounting Height
The hood must be at least as wide as the stove or cooktop beneath it, if not six inches wider. A 30-inch stove should ideally have a 36-inch hood to capture peripheral smoke and grease, especially for island or canopy installations. For optimal performance, hoods should be mounted 20 to 24 inches above electric ranges and 24 to 30 inches above gas ranges.
Your local public power provider, in partnership with Nebraska Public Power District, wants to help you make the most of the energy they provide. That includes helping you comfortably create culinary creations while using your kitchen in the most efficient manner possible. In addition, they may offer EnergyWiseSM incentives to reduce the initial costs of efficiency improvements. Contact your local utility or visit www.energywisenebraska.com for additional details.


