Type I and Type II hoods do different jobs: Type I handles grease-laden vapor, Type II handles heat, steam, and moisture. These answers explain which appliances need which hood, the ductwork and cleaning differences, cost, make-up air, and how to tell them apart. Codes vary, so confirm your requirements with the AHJ.
A Type II hood looks similar to a canopy or a lower-profile wall hood, but it is built for heat, steam, and moisture rather than grease. Condensate versions have a sloped, gutter-lined interior and drains to catch water instead of grease baffles, and heat-and-fume versions may just be a simple canopy with light filtration. It connects to lighter ductwork than a Type I and has no fire-suppression nozzles underneath.
Type II hoods serve appliances that produce heat, steam, moisture, or odor but not grease-laden smoke: dishwashers (condensate hoods), pressure and convection steamers, steam kettles, some ovens and proofers, and similar equipment. If the appliance mostly gives off water vapor and heat rather than grease and smoke, a Type II hood is the match. Grease- and smoke-producing equipment always needs a Type I hood instead.
A condensate hood is a Type II hood designed to capture steam and moisture, most often over a dish machine or steamer. Instead of grease baffles, it has a sloped interior and a gutter or drain to collect the condensing water so it does not drip on staff or floors. It removes the humidity and heat that would otherwise fog the area and damage finishes. It is not built for grease and cannot replace a Type I hood.
Generally no. Because Type II hoods handle heat, steam, and moisture rather than grease, they do not require the listed grease baffle filters that a Type I hood must have. Condensate versions instead use baffles or gutters to manage water, and heat-and-fume versions may have light filtration or none. If an application actually produces grease, it needs a Type I hood with grease filters, not a Type II.
Commercial dish machines throw off a lot of hot steam, so they are commonly fitted with a Type II condensate hood to capture the moisture and heat and keep it from damaging ceilings and fogging the area. Some low-temp machines or specific layouts may not require one, but many jurisdictions expect condensate control over high-temp machines. It is a Type II, not a grease hood. Confirm the requirement with your local code and the machine spec sheet.
A pressure or convection steamer and steam kettles produce significant moisture and heat and are typically ventilated with a Type II condensate hood. A heated steam table (holding food, not generating steam under pressure) usually produces far less and may not need a dedicated hood, though local code varies. The rule of thumb: heavy steam and moisture point to a Type II hood. Verify with your AHJ and the equipment documentation.
It depends on what you cook. A convection or combi oven that mainly produces heat and steam often needs only a Type II hood, but if you roast fatty meats or otherwise generate grease-laden vapor, a Type I grease hood is required. Manufacturers publish ventilation requirements for each model, and some are listed for limited ventless or Type II operation. Match the hood to the actual grease load and the manufacturer and code guidance.
Many coffee shops with only espresso machines and low-heat equipment need no hood, or at most Type II for an oven or dish machine. Bakeries that only bake in ovens often need Type II for heat and steam, while those frying (doughnuts) or producing grease need a Type I hood. It comes down to whether you generate grease-laden vapor. Confirm with your AHJ, and the do I need a hood tool can help you check.
No. Fryers, griddles, ranges, and charbroilers produce grease-laden vapor and require a Type I grease hood with filters, welded grease duct, and fire suppression. A Type II hood has no grease filters or suppression and would let grease build up in the duct, a serious fire hazard and an automatic code violation. Always use a Type I hood over grease- and smoke-producing cooking equipment.
No. Any cooking that releases grease-laden vapor must be under a Type I hood, full stop. A Type II hood is only for heat, steam, and moisture and lacks the grease filters, welded liquid-tight duct, and fire suppression needed to handle grease safely. Cooking greasy food under a Type II hood coats the duct with flammable grease and fails inspection. Move that equipment under a proper Type I system.
Low-heat equipment like food warmers, proofers, and hot-holding cabinets usually produces little grease or steam and often needs no hood, though heavy steam from a proofer may call for Type II heat-and-moisture ventilation. They rarely require a Type I grease hood. Because local codes and specific equipment vary, check each appliance's ventilation listing and confirm with your AHJ rather than assuming any heated cabinet needs a hood.
Type I grease ductwork must be welded liquid-tight steel, sloped to drain grease, run with minimum bends to an exterior discharge, kept clear of combustibles or wrapped, and cleaned per NFPA 96, because it carries flammable grease. Type II ductwork handles heat, steam, or moisture and can be lighter, non-welded duct (sometimes with corrosion-resistant material for condensate), with far less stringent fire requirements. The grease hazard is why Type I duct rules are so strict.
Yes. Type I grease duct must be welded and liquid-tight so grease cannot leak into wall or ceiling cavities where it could feed a fire. It is sloped to drain, has access panels for cleaning, and maintains clearance to combustibles or a listed enclosure, all per NFPA 96. Taped, screwed, or standard HVAC duct is not acceptable for grease. This welded construction is one of the biggest cost and code differences from Type II.
Yes. Because Type II hoods carry heat, steam, or moisture rather than flammable grease, their ductwork does not need to be welded liquid-tight grease duct. It can use lighter gauge or standard duct, though condensate applications often use corrosion-resistant material and slope to a drain to handle water. Fire-clearance rules are much lighter than for Type I. Still follow the mechanical code and your AHJ for the specific installation.
Some heat-and-fume Type II applications can recirculate or use short venting because they are not moving grease or combustion products, but this depends entirely on the equipment listing and local code, and steam or condensate loads usually still need to be ducted out or drained. Do not assume ductless is allowed. A Type I grease application generally cannot recirculate unless it is a specifically listed ventless appliance. Confirm any recirculating setup with your AHJ.
Because Type II hoods handle heat and moisture rather than grease, their exhaust routing is more flexible and may terminate through a wall or shorter run rather than a full welded rooftop grease stack, subject to code. Condensate must still be drained and moisture discharged where it will not cause damage. This flexibility is a real advantage over Type I. The exact routing is code-dependent, so verify allowable terminations with your AHJ.
It needs cleaning, but not the rigorous NFPA 96 grease-cleaning regimen a Type I hood requires. Type II hoods collect heat, steam, mineral scale, and light dust rather than flammable grease, so cleaning focuses on hygiene, condensate drains, and any filters. Type I hoods must be professionally degreased on the NFPA 96 schedule because grease is a fire hazard. Keep Type II hoods clean for sanitation, but the fire-driven cleaning rules are lighter.
A Type II hood skips the most expensive Type I requirements: welded liquid-tight grease duct, listed grease filters, a fire-suppression system, and strict clearance and cleaning rules. Its ductwork is lighter and routing more flexible. That means lower material, labor, and ongoing service costs. The tradeoff is that a Type II hood can only serve heat, steam, and moisture, so grease-producing equipment still needs the full, costlier Type I system.
Any hood that exhausts a meaningful volume of air needs make-up air to replace it, or the space goes negative and the hood cannot pull its rated airflow. Large Type I systems almost always require a dedicated make-up air unit. Smaller Type II exhaust may be balanced by the building HVAC or a smaller make-up air source. Either way, exhaust and make-up air are sized together; see ventilation and make-up air explained.
Yes. Combination hoods exist that have a Type I grease section over cooking equipment and a Type II section over adjacent heat or steam equipment, or utility distribution built in. Each section still follows its own rules, so the grease portion needs filters, welded duct, and suppression while the Type II portion does not. Combination hoods can save space and cost on mixed lines, and they are engineered and permitted as a unit.
List your equipment and ask whether each piece produces grease-laden vapor. Fryers, griddles, ranges, charbroilers, and woks require a Type I grease hood; dishwashers, steamers, and heat- or moisture-only equipment need a Type II hood; low-heat items may need nothing. Kitchens with a mix often need both, sometimes in a combination hood. Sizing then follows the equipment duty. Confirm the final call with your AHJ, and the do I need a hood tool helps you start.
UL 710 is the safety standard that Type I grease hoods are tested and listed to. A listed hood has been evaluated for construction and for how much exhaust airflow it needs to capture and contain grease, and it comes with the manufacturer's certified minimum CFM. Using a listed hood can allow lower, energy-saving exhaust rates compared with a prescriptive field-built hood. Follow the listing data and confirm acceptance with your AHJ.
Often, yes. Because a listed (UL 710) hood has been tested to prove it captures grease at a certified airflow, it can carry a lower exhaust rate than the conservative prescriptive value a field-built hood must use, which cuts exhaust and make-up air CFM and saves energy. The savings depend on the model's listing. Use the manufacturer's certified minimum airflow, and confirm the reduced rate is accepted by your local code official.
Grease-laden vapor is the airborne mix of grease droplets, smoke, and heat given off when you fry, griddle, broil, or roast fatty foods. As it cools it condenses into sticky, flammable grease that coats filters and ducts, which is a serious fire risk. A Type I hood is built to capture that grease with baffle filters, carry it in welded duct, and protect against fire with suppression. That fire hazard is why grease demands Type I.
Because a Type II hood moves heat, steam, or moisture rather than flammable grease, it does not require the fire-rated grease-duct clearances, enclosures, or suppression that a Type I system does. It still must meet general mechanical-code clearances and, for condensate, handle water safely. This lighter requirement is part of why Type II is cheaper. Always confirm the specific clearances with the manufacturer and your AHJ for your installation.
Yes, a Type I hood over-serves a heat or steam load and will work, but it is rarely worth it. You would pay for grease filters, welded duct, fire suppression, and NFPA 96 cleaning you do not need. Where only heat, steam, or moisture is produced, a Type II hood does the job for much less. Match the hood to the load rather than over-building, unless a future grease appliance is planned there.
Yes. Installing either a Type I or Type II hood is mechanical work that requires permits, plan review, and inspection, and Type I systems add fire-suppression permitting and inspection. The AHJ checks construction, ductwork, clearances, airflow, and, for Type I, the suppression system before approving use. Never install a hood without permits, since it will surface at your opening inspection. See commercial kitchen permits and licenses.
Check the manufacturer's ventilation guidance and think about what the appliance releases: frying, griddling, broiling, and roasting fatty foods make grease-laden vapor (Type I); boiling, steaming, dishwashing, and plain baking mostly make heat and moisture (Type II). When in doubt, treat borderline cooking as grease-producing and confirm with your AHJ, since under-classifying is a fire and code risk. The do I need a hood tool walks through common equipment.