Range Hood Vent Code (2023 Requirements) (2023)

Probably the most important code requirement for range hoods is that they should vent outdoors.

Another important code is on the duct length and diameter of kitchen hoods.

The in-wall range hood duct should be made out of smooth metal and with a minimal amount of turns.

Range Hood Vent Code (2023 Requirements) (1)

As a home inspector, I have inspected many range hoods over the years, and clients frequently ask me about building codes. Even though inspectors aren’t code inspectors, we do like to familiarize with building codes and best practices.

In this HomeInspectorSecrets.com code guide, I will go over…


  • Minimum duct length & diameter
  • Minimum CFM or fan speed
  • How range hoods vent to the outside
  • Makeup air systems for high powered vent hoods

Kitchen Hood Vent Codes Are Based On The IRC And Your Local Code

7 Building Codes For Kitchen Vent Hoods

Makeup Air Venting Code Prevents Carbon Monoxide Poisoning

Final Thoughts

(Video) Kitchen Rangehood Ventilation Solutions

Kitchen Hood Vent Codes Are Based On The IRC And Your Local Code

Range hood vent code requirements are laid out in the IRC or the International Residential Code.

The IRC is a ‘model code’ that many U.S. states and counties base their code on. For the final say on any code matter, you will need to consult your local state or city building codes or even a quick call to your local building department.

Range Hood Vent Code (2023 Requirements) (2)

Even though I summarize the code requirements (I just looked at some of the most important issues), this isn’t exhaustive of every single code and exception.

As a side note, older houses are almost usually ‘grandfathered in’ and not required to adhere to newer code requirements except for new installations.

Read Also >> What Are The Building Codes For Dryer Vents?

7 Building Codes For Kitchen Vent Hoods

1. Must Vent To Outside

Range hoods always need to vent to the exterior. They can’t exhaust into an attic, a crawlspace, or inside a ceiling cavity.

The main code exception is for ductless or recirculating range hoods as long as they are listed and designed for that type of installation. Recirculating range hoods always require the addition of a carbon filter which helps catch smoke and smells.

Here are a few other code requirements on how range hoods exhaust…

  • Interior of the duct should be smooth (no ridges)
  • Range hood duct needs to be air tight
  • Hood needs to have a backdraft damper (a damper or ‘flap’ closes the vent when the hood is not in use)
  • Exhaust duct needs to be independent and not connected to any other exhaust system such as a bathroom fan

Read Also >> Do Kitchen Vent Hoods Have To Be Vented Outside?

2. Ducting Material

Range hood ducts always need to be either galvanized steel, stainless steel, or copper.

The one big exception to this code is if the range hood is a downdraft type (it sucks in air downwards and the vent goes into the floor).

With a downdraft hood, it is permissible to use PVC plastic piping instead of metal under certain conditions.

(Video) What Is Make Up Air? What to know before you get a powerful hood.

3. Makeup Air System May Be Required

If you have a range hood that is rated at 400-cfm or greater, you may be required to have a makeup air system installed. Makeup air systems are automated devices with dampers that brings in fresh outdoor or to replace the air exhausted by the range hood.

This code requirement only applies to gas or propane ranges and if it isn’t already direct vented.

The makeup air unit also needs to have a damper which closes when not in use so outdoor air doesn’t leak into the home.

There are universal makeup air systems on the market that uses a sensor to open the damper if it detects the range hood turned on. These systems only need low voltage wiring and they work well with new construction or existing kitchen hoods.

Read Also >>What Are The Building Codes For Bathroom Fan Venting?

4. Duct Length

The code requirements for the duct length of range hoods is based on the duct diameter, whether it is smooth walled, and it’s CFM rating.

For example, if your range hood is rated at 200-cfm, and the flex duct has a 6-inch diameter, then the maximum duct length is 18-feet. And a 5-inch diametersizedduct or below isn’t even permitted with a 200-cfm hood and 6-inch flex duct.

Range Hood Vent Code (2023 Requirements) (3)

The exception to this section is if the range hood satisfies the requirements of the manufacturer or if you independently test the air flow of the hood with some type of measuring device.

The X marks in the table provided below means that under these conditions a duct is not allowed because of the high pressure drop.

5. Exterior Cover

Range hood vents should always be located on the outside and they need to terminate at least 3-feet away from windows, doors, and other vents such as bathroom fans.

If you have a powered air intake such as from a high efficiency furnace, then the range hood vent needs to be at least 10-feet away. The exception to the 10-foot rule is if the range hood vent is at least 3-feetabovethe intake vent.

(Video) How To Run a Vent For a Range Hood

6. Minimum Exhaust Rate Or CFM

The absolute minimum CFM for a kitchen range hood is 100-cfm.

CFM stands forcubic feet per minuteand it is a range hood rating for how much air the hood can exhaust every 60-seconds. Most range hoods are in the 150-350 cfm range.

Range Hood Vent Code (2023 Requirements) (4)

7. Must Use Individual Or Dedicated Branch Circuit

Range hoods need to be supplied by an individual branch circuit.

For higher powered range hoods, a dedicated circuit will be needed.

The minimum cord length will be 18-inches and the maximum cord length is 48-inches.

Read Also >> What Are The Building Codes For Dryer Vent Installations?

Makeup Air Venting Code Prevents Carbon Monoxide Poisoning

The main reason for the makeup air code requirement (code #3 above) for some range hoods is to prevent a carbon monoxide hazard.

If you have a very strong range hood, it will create a largeair pressureimbalance in the home (negative air pressure) which can possibly create a backdrafting scenario.

Backdraftingis when negative air pressure actually reverses the flow of the exhaust gases into the home. If exhaust gases are going into the home rather than to the exterior, carbon monoxide poisoning can occur.

Makeup Air Should Go Into Kitchen

If you need a makeup air system by code, the ‘makeup’ or fresh air needs to be sent into the kitchen or room where the range hood is located.

The exception to this rule is that it can go into a different room as long as they are connected by a permanent opening.

The type of damper for the makeup air system should work either by gravity (opens and closed based on air flow) or it can be electronically operated. The electric dampers open automatically when the range hood is turned on.

Read Also >> What Are The Building Codes For Gas Water Heater Venting?

Final Thoughts

The biggest takeaway for range hood code requirements is that they need to vent to the outside. They can’t vent into a crawlspace or an attic.

Also, there are duct requirements for safety such as the length and the type of material used. If you use too small diameter of a duct, it can cause a pressure drop, and create a hazardous situation.

(Video) Sizing & Calculating CFM for Kitchen Range Hoods over Gas Cooktop

Another important code requirement is for makeup air.

If your range hood is 400-cfm or greater, you may need to install a makeup air system to prevent a dangerousbackdraftingsituation with carbon monoxide poisoning if you have fuel-burning appliances.


What is code for a range hood? ›

Although the international CFM code for range hoods is 100CFM, some local authorities allow for range hoods with slightly lower or higher CFM than this, depending on the type of your cooking, and the square footage of your cooktop.

Is it against code to not have a vent hood? ›

In the International Code manual, residential vent hoods are not specifically required.

How much CFM is enough for range hood? ›

Wall-mounted & Under-cabinet range hoods – 100 CFM for every linear foot of cooktop. Most common types of cooktops measure 30 inches wide, or 2.5'. To meet the recommended CFM requirements, you'll need a range hood with 250 CFM. Island hoods – 150 CFM for every linear foot of cooktop.

Is there a code for range hood height? ›

In most states in the USA, the average height from the top of the cooking range to the bottom of the range hood is 18”, and it is the minimum height clearance required by most building codes.

What makes a vent hood ADA compliant? ›

To comply, The Department of Justice ADA standards section 309 states the range hood control must be placed within reach and shall be operable with one hand and shall not require tight grasping, pinching, or twisting of the wrist Also, range hoods are typically installed 24-30” above a cooktop or 60-66” above the floor ...

What is the NFPA code for kitchen hoods? ›

NFPA 96: Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations.

Are you required to have a hood vent over your stove? ›

Though you may not be required to install a hood over your stove, it is generally recommended for the best cooking experience. Without one, smoke and fumes may build up in your kitchen. Range hoods also help to reduce heat and moisture while cooking so you may not even break a sweat when cooking dinner for your family.

What happens if you don't have a vent hood? ›

It is not safe to cook without a range hood. Everyday cooking produces harmful contaminants including carbon dioxide, carbon monoxide, formaldehyde, and more. Without proper ventilation, these toxins sit in your kitchen and move to other areas of your home.

Are ductless range hoods legal? ›

Ductless range hoods are permitted by international construction laws. However, there should be additional natural ventilation or mechanical ventilation. The included ventilation source could be from a CFM blower, a hole to vent kitchen air or a duct attached to your range hood.

Is 1200 cfm enough for range hood? ›

To power your range hood, you need at least 100 CFM for every 10,000 BTUs of your stovetop. For example, a 100,000 BTU stove needs at least a 1000 CFM range hood. For electric stoves, multiply the stove width by 10. So, for a 42” electric stove you want a range hood with at least 420 CFM.

Is 500 CFM enough for range hood? ›

For gas cooking surfaces or range, a minimum ventilation level of 100 CFM (Cubic Feet per Minute) per 10,000 BTU is recommended. However, the hood must have a minimum of 500 CFM of ventilation power.

How many CFM do I need for a 12x12 room? ›

One cfm is needed per square foot (1 cfm/sq ft) of floor area. This is the average air quantity required for a room or an entire building.

What is minimum height for rangehood above gas cooktop? ›

If you have an electric cooktop, range hoods should typically be 20–24 inches above the heat source. For gas cooktops, your range hood should be around 24–30 inches above the stove. Range hoods are a great way to complement your cooktop or range and can help clear the air while you cook.

What is the maximum duct length for a range hood? ›

For optimum performance, make sure that the air duct is short and straight, with a maximum length of 50 linear feet. Long radius elbows are preferred to short radius elbows for better air intake. Note: Each elbow is equivalent to 10 linear feet of duct.

How far out should a range hood stick out? ›

If possible, it is ideal for the hood to extend three inches on each side of the range. This margin allows for a large capture range. The measurement between the top of the range and the bottom of the hood is also an important consideration. For gas cooktops, the hood should be 24 to 36 inches away.

What are general rules for hood design? ›

What are the general rules for hood design?
  • The hood should be placed as close as possible to the source of contamination, preferably enclosing it. ...
  • The air should travel from source of the contaminant and into the hood with enough velocity (speed) to adequately capture the contaminant.

Is it OK to use flexible duct for range hood? ›

No, do not use flex duct for your range hood. Most flex duct is made of cheap materials and will not last nearly as long as semi-rigid or rigid duct. You run the risk of having to clean or replace your duct which is quite expensive.

What is the difference between a Type 1 and Type 2 vent hood? ›

So to break it down as simple as possible – go with a Type 1 Hood for cooking equipment that can lead to grease and grease by-products, and go with a Type 2 Hood for other kitchen appliances and equipment that require removal of heat and moisture.

What are the NFPA 25 requirements? ›

According to NFPA 25, the property owner or designated representative is accountable for the fire protection system's overall maintenance. During monthly inspection, the on-site fire protection person should examine the pipe system gauges, ensure water pressure maintenance, and inspect the alarm valves.

Is it code to have an exhaust fan in the kitchen? ›

However, kitchen exhaust fans play a big role in maintaining good, safe air quality in your home and protecting the health of your family. So while there is no building code that says you have to have a residential kitchen exhaust system, you will probably want to install one anyway.

What is code for venting a gas stove? ›

There's no national code for gas venting in the United States. Generally, in the U.S., you don't have to vent a residential gas range to the outside. But, we recommend that you buy a range hood to vent contaminants from your gas range to outside your home.

Do you have to have an exhaust fan over a gas stove? ›

Across the United States, the majority of residential homes cooking with gas do not need to vent their range. However, just because you don't have to does not mean that you shouldn't. If you use a commercial-style range, then you will be required to do so.

Can you use a ductless range hood with a gas stove? ›

A non ducted or ductless range hood is not the best option for gas stoves because they work by filtering the air inside the hood and returning it into the kitchen. Even if you have a hood with a high CFM rating, charcoal filters will not capture all the gas produced by the stove.

Do range hoods have to be vented outside? ›

Do range hoods have to be vented outside? No; range hoods without a duct, or ductless range hoods, can recirculate air back into your kitchen. However, to clean your kitchen air most efficiently, purchase a ducted range hood. Rather than relocate the cooking exhaust, it will evacuate it from your home entirely.

Does a range hood need to be GFCI protected? ›

If it is within 6 feet of the sink it must also be GFCI protected even if the receptacle is located behind the range. Same thing with the small appliance, range hood, microwave, dishwasher, garbage disposal, refrigerator and other kitchen circuits.

What is the difference between a Type 1 and Type 2 Hood? ›

So to break it down as simple as possible – go with a Type 1 Hood for cooking equipment that can lead to grease and grease by-products, and go with a Type 2 Hood for other kitchen appliances and equipment that require removal of heat and moisture.

Does a hood need a dedicated circuit? ›

Does a range hood need a dedicated circuit? No. A range hood can run on a circuit with more than one appliance. The most important thing to watch out for though is overloading the circuit.

Do you need a vent hood for an electric stove? ›

The truth is that you should consider a vent for your electric stove. Even if you cook one or two times a week, a vent hood can be beneficial for you. It will clean your indoor air and improve your indoor air quality. For electric stoves, we recommend a range hood of at least 600 CFM.

Can non vented range hoods be effective? ›

Unvented range hoods do filter some grease and cooking odors from the air, but the general consensus is that they're nowhere near as effective. Nor do they remove heat and humidity, so they won't help keep your kitchen cool while you cook.

Do you hardwire or plug in range hood? ›

If your range hood came with a three-pronged plug, it does not need to be hard-wired. Just plug the hood into a wall outlet and use an extension cord if necessary. If it did not come with a three-pronged plug or it came with a cut plug, the hood needs to be hardwired.

Can microwave and range hood be on same circuit? ›

A combination microwave/hood cannot be connected to the either of the two required kitchen small appliance receptacle circuits because it is not a countertop (portable) appliance, per National Electrical Code [NEC 210.52(B)(2)].

Where should an outlet be placed on a range hood? ›

Q: Do I need to hardwire or plug in the hood? All wall mount range hoods today come with a wire with a plug, you will need to provide a power outlet behind the chimney cover, see the above diagram.

Is higher CFM better for range hood? ›

Simply put, the higher the CFM, the more air the hood vents out of your kitchen. To power your range hood, you need at least 100 CFM for every 10,000 BTUs of your stovetop. For example, a 100,000 BTU stove needs at least a 1000 CFM range hood.

What is the most efficient range hood? ›

There are three vent types for kitchen ranges: ducted, ductless, or convertible. The most common and efficient type is a ducted range hood. This allows the fan to exhaust kitchen air outside.

What type of duct is best for venting a range hood? ›

Rigid duct is the best type of duct to vent your range hood. It requires a one-time installation and little to no maintenance as long as you clean your range hood filters. Most rigid ductwork is made from durable stainless steel, as opposed to rigid ductwork which is aluminum or flimsy plastic.


1. Vented vs Recirculating Cooker Hoods | Pros, Cons & Advice
2. Ducting Do's and Dont's for Vent A Hoods - Kitchenfoundry.com
(erik bergstrom)
3. 5 Best Range Hood 2023 [RANKED] | Range Hoods Reviews
4. Broan BXT 130 SS Range Hood Installation and Wiring.
(Daily Home Repairs )
5. Choosing a Range Hood & What To Know Before Buying a Range Hood
(Victory Range Hoods)
6. Gas-rated Range Hoods Are Need for Gas Ovens
(Peterson Electric)
Top Articles
Latest Posts
Article information

Author: Geoffrey Lueilwitz

Last Updated: 05/30/2023

Views: 6009

Rating: 5 / 5 (80 voted)

Reviews: 87% of readers found this page helpful

Author information

Name: Geoffrey Lueilwitz

Birthday: 1997-03-23

Address: 74183 Thomas Course, Port Micheal, OK 55446-1529

Phone: +13408645881558

Job: Global Representative

Hobby: Sailing, Vehicle restoration, Rowing, Ghost hunting, Scrapbooking, Rugby, Board sports

Introduction: My name is Geoffrey Lueilwitz, I am a zealous, encouraging, sparkling, enchanting, graceful, faithful, nice person who loves writing and wants to share my knowledge and understanding with you.