You should take venting seriously.
I walked by this range hood this morning on my way to the gym.
Ventilation hoods were always the last appliance you bought after hours of stressing the type and brand for your range.
In many ways, venting is the most important appliance you will buy.
Yet, most don't take it seriously - even manufacturers.
Recent studies suggest the air in our homes is worse than the air outside. Poor ventilation is one of the top reasons ahead of cigarette smoking.
IAP (Internal Air Pollution) and IAQ (Internal Air Quality) are now terms describing the air in our homes.
Ventilation planned well can reduce the problem of air pollution in your home.
In this article, you will learn how high to hang your range hood. Then we will show you how to vent properly.
Let's get started.
How High Do You Hang a Range Hood?
For gas cooking, a range hood should be at a minimum of 30 inches from the stovetop to the bottom of the hood.
It should not deviate beyond the minimum or maximum for safe and effective cooking.
There are varied factors to consider for several types of hoods, such as whether your hood is going above an outdoor or indoor unit.
If you are placing a hood above a professional range, your range will need to be between 30–36-inches from the hood.
Because professional ranges have high outputs, this ensures the most capture area for all the smoke and carbon monoxide emitted from the stove.
For professional gas cooking, the most common hood is the 18-inch canopy hood (shown above), which is recommended to be anywhere from 30-36 inches above the range.
A chimney hood (shown above) would need a minimum of 30 inches between the range and bottom of the hood itself.
The other commonly found ventilation type above a gas range is the insert found inside wood cabinetry (shown above).
This type requires a spacing of 36 inches from the stove surface.
If you look at the diagram of the GE Profile over-the-range microwave below, they measure from the floor to the top of the microwave at 66 inches.
Your microwave would be roughly 16-18 inches over your stove.
Over a Grill
If your hood is going above an outdoor unit, the hood should be between 36-42 inches above the grill or cooktop surface.
Read More: How to Vent an Outdoor Grill
For electric cooking, a range hood should be between 24-32 inches from the stovetop to the bottom of the hood.
For an over-the-range microwave, the height from the stovetop doesn't necessarily matter since there is no flame.
Meanwhile, for induction cooking, the hood should be anywhere from 28-36 inches above the cooktop.
Six hundred CFM is pretty standard for induction cooking unless your hood is above a range that exceeds 42 inches, then you would need to upgrade to 900-1500 CFM.
For most induction and electric cooking, your options include an under-the-cabinet hood, a wall mount hood, or an island hood such as a downdraft.
How to Vent Properly
Venting is comprised of four elements, CFM, capture area, duct size, and duct run.
Let's explore each.
CFM is cubic feet per minute or how many cubes of air are extracted per minute.
A 900 CFM blower means 900 cubes of air are extracted per minute. That's roughly a small room of air.
How Much CFM Do You Need?
It varies depending on how you cook and what you have for a stove.
If you like to grill, griddle, fry, or use a wok, then 900 to 1500 CFM is needed to extract the odor and grease from that type of high volume cooking.
For boiling water, you may need only 400 CFM or less.
Types of Blowers
Inside: Located inside the hood, it's easier to service, but you do hear more noise.
Outside: Exterior blowers can be purchased in higher CFMs. They also are quieter, but you still hear the air rushing through the duct.
However, they are not easy to fix in the winter, and having a huge stainless steel mushroom cap on your house is not exactly good-looking.
In-Line: Mounted to the duct run, you have the quieter operation of the outside blower without the big motor outside your home.
Pro Tip: If you are planning an inline blower, then you need to build an access door in case you need service.
Capture is the most misunderstood aspect of ventilation. It's roughly the height, width, and depth of the hood.
Smoke is chambered, then exhausted. It's not immediately sucked out of your home. For high-volume cooking, buy a hood with a minimum of 24 inches in depth.
The power burners of most gas ranges are in the front at about 24 inches deep.
Ideally, you should keep a vent duct below 30 feet because the longer and more bent the duct, the less effective the venting will be.
Some ducts do tend to go 60-70 feet. Most that do, like downdrafts, won't work.
Each elbow turn is equivalent to 6-8 feet of ducting, so you should rethink the duct pathway if the duct exceeds one elbow turn.
The best way to the duct is vertically, straight, and short. The next best is horizontally and short.
Duct size is a lot like capture area. Larger ducts will be able to exhaust more smoke, so use at least 6 inches. On the larger CFM blowers, you will need 8 or 10 inches.
Use a rigid duct only. Grease can be caught in the joints of a flexible duct. It's against code in many states.
For new construction, any vent over 400 CFM needs the equivalent fresh air return.
It's simple in new construction. Just plan for Make-Up Air as part of your HVAC.
The code in Massachusetts is 10 feet away and on the opposite wall if you want to retrofit it.
Read More: What Is Make-Up Air?
Ventilation Hoods to Avoid
BEST Downdraft behind the cooktop
Ventilation mistakes have been a big part of our webinars. Our "Appliances You Should Never Buy" webinar featured downdrafts as the number one appliance you should avoid.
Downdrafts reverse gravity and have zero capture area. Most of the power burners are now on the front of ranges, and yet a downdraft is behind the range.
Read More: Can You Install a Downdraft Vent Behind a Range?
Samsung Over-the-Range Microwave above a freestanding gas range
Over-the-range microwaves centralize your cooking. I love them as a concept, yet their CFM is only 310 with little capture area.
You may want to think about a hood and placing the microwave elsewhere.
Read More: Are Over-the-Range Microwaves Going Out of Style?
BEST Cirrus Hood inserted into the ceiling
These hoods are new, Italian-inspired, and beautiful. However, by placing the hood in the ceiling, some of the smoke will dissipate before being extracted.
If you cook a lot, then I would consider other options.
Figuring out how to hang a hood is fairly simple. Venting correctly is much harder.
You have to plan the right CFM, capture area, and plan the duct accordingly.
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