Cooking adds heat, grease, combustion byproducts, and a surprising amount of water vapor to your air, and a recirculating fan removes almost none of it.
The kitchen is the busiest indoor pollution and moisture source in most homes, yet range hood venting is one of the most misunderstood parts of home performance. Boiling, steaming, and simmering all release water vapor; searing and frying release grease particles and odors; and gas burners add combustion byproducts on top of everything else. A range hood that vents outdoors captures all of it, while a recirculating hood mostly just moves it around. In humid North Texas, where indoor moisture is already hard to shed, understanding kitchen venting is an important part of humidity control and healthy indoor air quality. This guide breaks down what cooking really adds to your air, how ducted and recirculating hoods differ, and how to vent a kitchen the right way.
A range hood is not just about clearing smoke when something burns. Everyday cooking continuously loads the indoor air with several things at once, and each one matters for comfort, durability, and health.
Only a hood that ducts to the outdoors removes all of these from the home. A recirculating unit can trap some grease and odor in filters, but it returns the heat, moisture, and combustion gases right back into the kitchen. That distinction is the heart of good kitchen venting.
Homeowners tend to think of bathrooms as the wet rooms and kitchens as the smelly ones, but kitchens generate large amounts of water vapor too. A big pot at a rolling boil can release the better part of a pint of water into the air in a matter of minutes, and holiday cooking or canning can run several burners for hours.
That vapor behaves exactly like shower moisture. Warm, humid kitchen air rises and spreads, and when it reaches a cooler surface and drops below its dew point, it condenses. Repeated over months, that feeds the same mold and material damage we cover in condensation and mold prevention.
In a leaky older home, some of this moisture escapes through random gaps, though usually to the wrong places like wall cavities and the attic. In a tight, well sealed home built with spray foam air sealing, that moisture has nowhere to go unless you exhaust it on purpose, which makes a properly ducted range hood more important, not less.
There are two fundamental types of range hood, and the difference determines how much they actually help.
A ducted hood pulls kitchen air through a filter and then blows it through a duct to an exterior termination, removing heat, moisture, grease that gets past the filter, combustion gases, and odors from the home entirely. A recirculating hood pulls air through a grease filter and often a charcoal filter, then blows that air straight back into the kitchen. It can capture some grease and reduce some odor, but it does nothing about moisture, heat, or combustion byproducts.
For a home with a gas range especially, a ducted hood is the clear best practice because it is the only reliable way to remove combustion pollutants at the source. Recirculating hoods exist mainly for situations where ducting to the outside is truly impossible, such as certain interior island or high-rise layouts, and even then they are a compromise rather than a solution.
Range hoods are rated in cubic feet per minute, or CFM, and the right number depends on the cooktop, the layout, and how you cook. Too little airflow and the hood cannot capture the plume of steam and smoke; too much airflow in a very tight home can cause backdrafting problems that need attention.
In tightly sealed homes, a powerful hood moving several hundred CFM can depressurize the house and pull air backward down flues or fresh air intakes. That is a solvable problem with makeup air, and it is one more reason kitchen venting should be planned alongside the home's overall fresh air ventilation strategy.
As with bathroom fans, the duct makes or breaks the range hood. Kitchen exhaust adds grease to the equation, so smooth, cleanable, correctly terminated duct is essential.
Venting a range hood into the attic is the same mistake as venting a bathroom fan there, only worse, because you add grease to the moisture. It coats the framing and decking, feeds mold, and creates a genuine fire concern. If your attic has been sealed into the conditioned envelope, as described in the conditioned attics guide, the duct must pass fully through the foam and terminate outside.
Every cubic foot of air a hood blows outside has to be replaced by a cubic foot coming in from somewhere. In a leaky home, that replacement air sneaks in through countless gaps. In a tight, well sealed home, a powerful hood can pull the house into negative pressure, which can cause backdrafting of combustion appliances or simply choke the hood so it cannot move its rated airflow.
The solution is makeup air, a controlled supply of outdoor air that opens when the hood runs. Larger hoods, particularly over gas ranges in tight homes, may require a dedicated makeup air system by code. This is closely tied to how the whole home breathes, a topic we cover in fresh air ventilation and in the choice between an ERV and HRV.
None of this is a reason to avoid sealing your home. A tight envelope built with air sealing is what makes controlled ventilation possible in the first place. The principle building scientists use is build tight and ventilate right, which means seal the random leaks and then provide deliberate, well designed exhaust and supply where you actually need them.
Kitchen moisture and pollutants do not stay in the kitchen. Warm, humid cooking air rises and is pushed through the house by the stack effect, carrying grease and odors to upper floors and moisture toward cool surfaces where it can condense.
Removing that load at the source lightens the work your air conditioner and any dehumidifier do to keep the home comfortable, which supports overall humidity control. It also keeps combustion byproducts from a gas range out of your breathing air, a direct win for indoor air quality.
Think of the range hood as part of the same family as your bathroom fans and dryer vent: three point-source exhaust systems that each remove a specific, concentrated load before it can spread and cause trouble.
Does a recirculating range hood remove moisture? No. A recirculating hood filters some grease and odor but returns the air, along with its heat, moisture, and any combustion byproducts, right back into the kitchen. Only a ducted hood that terminates outdoors removes moisture and gases from the home.
How much airflow do I need for a gas range? A common approach is about one CFM per 100 BTU of total burner output, so a large gas range can call for 600 CFM or more. Capture area and mounting height matter as much as raw CFM, and big hoods in tight homes usually need makeup air.
Can I vent my range hood into the attic? No. Kitchen exhaust carries grease and moisture that will coat framing and decking, feed mold, and create a fire risk. The duct must terminate outdoors through a proper cap, a point that echoes the broader attic ventilation myths discussion.
Do I need makeup air? If you have a powerful hood in a tightly sealed home, likely yes. Without makeup air the hood can depressurize the house, backdraft combustion appliances, or fail to move its rated airflow. Makeup air is best planned alongside your home's fresh air ventilation.
Is a range hood still important in a spray foam home? Yes, more than ever. A tightly sealed home does not leak cooking moisture and pollutants out through random gaps, so a ducted hood is the deliberate path for removing them, working together with the home's overall ventilation plan.
Can Texas Foam Pro help route my kitchen exhaust correctly? During attic and envelope work we regularly find kitchen and bath ducts terminating in the wrong place and correct them as part of the job. A free instant estimate is a good starting point and lets us flag any venting problems we find.
Cooking loads your air with water vapor, grease, combustion byproducts, and heat, and only a range hood that ducts to the outdoors removes all of it. Choose a ducted hood over a recirculating one whenever possible, size it for how you actually cook, run smooth metal duct to an exterior cap, and plan for makeup air in a tight home.
Kitchen venting works hand in hand with bathroom venting, dryer venting, air sealing, and whole-home humidity control to keep your Texas home dry, healthy, and comfortable. If you want to know whether your kitchen and other exhausts are venting where they should, a free instant estimate and inspection is the fastest way to find out.
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Get a free instant estimate for your Dallas-Fort Worth home, and we will check whether your range hood and other exhaust fans vent outdoors and support a dry, healthy indoor environment.