A Range Hood Run Down: Kitchen Ventilation Basics

Guest Blogger: Mike Flahaven of Shady Oak Distributing

Mike Flahaven, of Shady Oak Distributing, is our trusted partner and rep for Vent-A-Hood Ventilation Systems and Range Hoods. We invited Mike to share his wisdom and experience in a blog on the importance of kitchen ventilation.

Kitchen “Ventilation”

As homeowners, many of us have had experience with an Over the Range microwave (OTR) and fan combination. In addition to filtering air, OTRs save space by getting your bulky microwave off the countertop.

However, an OTR actually recirculates contaminates that have been caught by the fan and filters. While they do have filters, an OTR provides very little, if any, meaningful ventilation because the air is recirculated back into the room. An OTR can also be vented to the outside where the resulting performance is improved, but only marginally.

The same ducting options apply to many range hoods. Like an OTR, recirculating range hoods simply cannot remove all the contaminates produced when cooking.

Today, we will cover the basics and share with you the importance of filtering your air and how to achieve great ventilation in your space.

What is the purpose of a range hood?

Odor Removal

We’ve all cooked in our home and ended up with that smell lasting for days. Whether we fry a pan of bacon, sauté onions, or make stir fry, in most homes the smell can linger for days. Those odors end up in our clothes, our hair, and our upholstery. Have you ever gone to a party and had to throw your clothes in the laundry after getting home? Yes? How nice would it have been if that home had good ventilation! With a properly functioning and outside-vented range hood, all odors are filtered out of your space so that your space stays fresh and odor free.


As with odors, the need for ventilating smoke is self-explanatory. Everyone can agree it would be nice to move the smoke out of the home when cooking. Whether you burn something by accident or blacken catfish on purpose, that smoke can mix with the rest of the air in the home and can linger for hours. Smoke is also an irritant and can cause harm to people and pets in a home!  Plus, smoke alarms generate annoying noise…right?


The amount of grease produced certainly depends on the type of cooking being done. An average family will easily produce a gallon of cooking grease per year, and that grease has to go somewhere!  When we cook fatty foods, some of the grease that we produce leaves the pan as grease vapor. Without a range hood, that grease vapor will travel throughout the home and condense onto nearby surfaces – notably your cabinets. I have been in many homes over the years where there has been no ventilation or poor ventilation and seen a sticky film all over the nearby cabinetry. Grease will ruin the finish on your cabinets!

Hazardous Gases

Ok, I did start with the easy reasons as to why a range hood. Everyone knows we can smoke and stink up our home when we cook. However, when we cook, we also produce gases such as carbon monoxide and nitrogen dioxide. Gas ranges produce the greatest amount of these hazardous gases. However, they are also produced when using electric and induction ranges, only in smaller quantities.

In short, it is very important to facilitate evacuating cooking contaminates and odors from the home.

How is good ventilation achieved? By venting to the outside!

Good ventilation is achieved by venting to the outside and taking into consideration three main things: the canopy, a blower system, and ductwork.


Your range’s blower system is effective in sucking particles and cooking by-products into the filtration system, but it’s the canopy that catches those contaminates and keeps them from escaping into your house. However, if there isn’t a properly sized and correctly located canopy above the cooking surface, it won’t matter what blower is installed in the hood because these by-products will not be properly filtered.

The ideal size of a range hood canopy is six inches wider than the cooking surface and covers the front burners. Space limitations can sometimes cause the canopy to remain the same width as the cooking surface and in cases like these, the narrower hood can be aided by the back wall and surrounding cabinets to help ventilate. However, when a hood that is mounted over an island, it is critical the canopy be larger than the cooking surface.

Blower System

The blower system should be sized based on the amount of heat being produced from the cooking equipment. The recommendation is one cubic foot per minute (CFM) of air movement for every 100 BTUs (300CFM for 30,000 BTUs). If using electric, you would calculate the wattage and roughly figure 300CFM for every 12,000 watts. When totaling the BTUs and watts, remember those totals are with all burners on high at the same time. Perhaps you only cook like that on holidays. Is that the time you want the hood to underperform?

IMPORTANT: Once the blower system has been properly sized, it is important to consult your local building codes and a HVAC professional. In many parts of the country, replacement air may be necessary to install as powerful range hoods can remove too much air from the house. When too much air is removed it can put the house in a negative pressure situation. When that happens, it’s possible to backdraft hazardous gases back into the house from other gas appliances such as furnaces and water heaters.


Range hoods work by moving high speed air, so it is important to have the correct ducting installed. If the following are taken into consideration, you will have a range hood performing properly and effectively:

  • Never restrict the size of the ductwork
  • Run the duct as short and straight as possible
  • Turns should be smooth and gradual (no hard 90 degree turns)
  • Seal all joints with foil tape
  • Enlarge the duct for runs over 20 feet

With a properly sized canopy, blower system, and correct ducting, you will be keeping cooking odors from mixing with the air in the rest of your home and imbedding into the walls, carpet, furniture, and drapes. And you will be keeping grease off your cabinets!

In addition to its functional uses, the range hood can play a large role in the aesthetics of a kitchen design! If you customize your hood in materials like copper and brass or use different color and shapes a hood can be a statement piece and a focal point in your design. And if you are looking for a more subdued look, a hood can be designed to seamlessly blend into your surrounding cabinetry. In some cases, when selling a home, Realtors will use the range hood as a selling feature!

For more information about range hoods or to learn more about our kitchen design process, visit our showroom or schedule an appointment with one of our designers today!