All you need to know about kitchen ventilation
Your cooking surface creates problems. We have names for these sinister problems like heat, steam, smoke, odor, gases and the worst of them all: grease. Of course the trade-off is cooking a delicious stir fry or perfect pan seared steak but nonetheless we need to kick these unwelcomed house guests out ASAP.
The solution to the problem is a ventilation hood. They’re designed to trap grease and remove contaminants from your house- seems simple enough but there are many kinds and they don’t all work the same. I’ll break down the types for you, but first let’s cover the basics.
First up: grease
Isn’t grease just left in the pan?
Not that easy- when grease gets hot enough it turns into grease vapor and ascends into the air.
Why can’t you just send grease out of your home with the other contaminants
Grease vapor is heavier than our other problems. If you send the grease vapor through your duct work, most of these large particles wouldn’t make it out, and instead cool down and hang out in your ducting.
What’s the problem with grease in the ducting?
The same reason why we love a greasy burger- it tastes good. Bugs like the taste too, so we don’t want to open an all you can eat grease buffet in our house. Even worse than opening a bug B&B in your walls is the chance of this grease heating up and starting a fire. Kitchen fires were responsible for 45% of all home structure fires last year. That’s one statistic I wouldn’t want to be a part of!
There’re a variety of ways we can trap this nasty grease.
Centrifugal:
We’ll start with my favorite way to separate the bad (heat and smoke) from the worst problems (grease). Centrifugal blowers send air in a circular motion before releasing it. This is the technology used by Vent-A-Hood’s Magic Lung line. If the air travels fast enough the large grease particles are flung to the outside and start hitting the walls inside the blower (which drip on a tray for cleaning).
Think of this as the Gulf of Mexico (albeit a simpler version of the Gulf). Water enters and travels in a circle. As the water makes a turn at a high speed along the Texas coast it dumps all the heavier dirt particles and we get left with the unspectacular Galveston beach. Cleaning your grease tray is simpler than cleaning Galveston though- just throw it in the dishwasher. Centrifugal blowers are the most efficient, easiest to clean option which makes them #1 for me.
Baffle Filters:
Baffle grease extractors are designed to change air direction quickly. The air is snaked through metal grates and grease droplets are deposited to grease traps. Remember grease particles are heavy so this quick change of direction traps the grease particles while allowing heat, steam, smoke, odor and other gases out of the house.
Although there are grease traps, you’ll have to still clean the filter. Many baffle filters are dishwasher safe which is a convenience but the grease gets tougher and tougher to clean as time goes on. Also, it’s important to note that baffle filters are not as efficient at trapping grease as centrifugal technology.
Mesh Filters:
Mesh filters separate grease from other contaminates by forcing air through metal meshing- thus trapping the larger grease particles. Think of the process as if you’re panning for gold. The pan lets the small sand and dirt particles to leave and keeps the larger nuggets in the pan. You won’t need to sell your new found gold to afford mesh filter ventilation either- it’s a cheaper option.
However, mesh filters are normally the least efficient option for trapping grease, and must be cleaned more often compared to our other grease extracting options.
So we’ve trapped the grease, let’s check out 3 other components that you should look for in a ventilation hood:
1. Canopy
Despite popular belief, the hood’s canopy serves a purpose. Imagine it as an upside down bucket that collects contaminants until the blower can remove them. You can get sleek looking glass, downdraft or flat hoods but know they won’t perform as well as a range hood with a true canopy.
2. Blower
This is the engine of your hood that moves air from the canopy and out through your ducting. The trendiest three letters in ventilation are CFM. CFM stands for cubic feet per minute and refers to the volume of air which can be moved every minute. The higher the CFM the more air that can be moved.
Choose a CFM based on your cooking style and cooking equipment. If you have a large cooktop or range, use multiple burners and emit a lot of contaminants in the air, then go ahead and get a vent with more CFMs.
If you’re on the other side of the spectrum and will only ever emit a little heat, steam and grease vapors then you can stick with a lower CFM level.
Although the CFMs you need changes depending on your cooking style, there’re some general guidelines we recommend. If you’re cooking on a gas cooking surface, you’ll want 1 CFM for every 100 BTUs. So if your cooking surface emits 60,000 BTUs, you should be good with a 600 CFM range hood. For electric cooking surfaces we recommend 600 CFMs for 30” and 36” surfaces, and 1000-1200 CFMs for 48” surfaces.
Remember to buy the hood that can handle your cooking on your busiest day- no one wants a smoke filled kitchen on Thanksgiving!
Types of blowers:
Many brands offer different options of blowers when you buy a hood.
Internal
Internal blowers are installed within the vent hood. They’re great for maintenance but can get loud. Vent-A-Hood’s Magic Lung line (yes, that one again) is the quietest internal blower you can buy, and as you increase CFM the noise increase is virtually unnoticeable. Check out our Vent-A-Hood sound test.
External
These blowers are installed on the outside of your home. You want to install them at least 15 ft. away from your cooking equipment or else they can be nosier than internal blowers. If installed far enough away, your unit will be quieter but any maintenance will require some time on a ladder or roof.
In-line
In-line blowers are installed in your ducting. They are fairly new on the market and are tricky to install and maintenance. The positive side of in-line is you don’t have an eye-sore on the outside of your house and depending on the install and size of blower, it can be quieter than an internal option.
3. Ducting
We made it to 3, hang in there! The keys to ducting are space and direction.
Space
The bigger the blower aka how much air flow you have, the larger the duct you’ll need. Just like you wouldn’t drain a swimming pool with a straw, make sure there is enough space for the air to exit! You’ll want to ensure your ducting is installed with consistent size all the way through- if you funnel air into smaller ducting, you’ll create a jam, contaminants will back up causing an overflow into your kitchen.
Direction
Install your ducting with gradual turns- a convoluted maze will not get the job done.
Size
For optimal performance you’ll want to hang your vent hood with 3” of overlap on either side of your cooking surface. If that’s not possible, for wall mounted hoods, having the same size hood as cooking surface is ok. Follow the 3” rule for island hoods as gas expands and can be unpredictable when introduced to blowing A/C currents, people’s draft while walking by and your kids having a wrapping paper tube fight in the kitchen.
Height and depth is also important. You’ll want the front of your hood to extend to the front of the front burners for best coverage. Again, air expands as it moves up, so you want to ensure your hood is installed 24”- 30” above your cooking surface. Any higher, you won’t capture the contaminants and any lower, it’ll be in your face- literally.
Make-up air
All that air being pumped out of your house needs to be replaced. In older homes, the natural cracks and leaks around doors and windows solves the problem but with newer construction you’ll need to consider a make-up air system. Having a system is a building code requirement in many areas. Make-up air systems will safely balance the air pressure in your home without going through dangerous carbon-monoxide producers like chimneys or water heaters.
Knowing the basics is important to choosing the right vent hood
These hoods are installed under your cabinet above the cooking surface. The ducting will either have to go through the cabinets or out the back of the unit. Under-cabinet range hoods save wall space but can take away cabinet space.
Wall-mounted hoods:
Wall-mounted hoods can create a design statement in your kitchen while providing functionality.
Island or chimney hoods:
Also called ceiling hoods, this type of hood is installed above a cooking surface on a kitchen island. Make sure island hoods overlap your cooking surface by 3” on each side.
Downdraft:
Downdraft ventilation is kept inside the cooking space until you need to use it. When you need to use the fan, it pops up along the back of your range. Downdrafts are not always as effective at capturing containments, especially when cooking on the front burners, but it’s an option for kitchens with limited space. If you have to go with a downdraft, I’d recommend buying the same brand as your cooking surface. If that’s not an option, look at Best downdraft systems.
Let’s wrap this up
When buying a range hood, keep in mind the canopy, blower and ducting has to work together for best performance. You’ll find many hoods without a canopy which are less efficient than having a dedicated collector. Choose a blower that fits your cooking surface output and cooking style. Installation should not be overlooked. Make sure the unit is the proper height and the ducting follows the rules of space and direction. Keep in mind you might have to install a make-up air system to replace the air that you’re pumping out.
As I mentioned earlier ventilation is not as simple as it seems. Make sure to keep these key points in mind when selecting your ventilation hood and you won’t be disappointed! Find a Factory Builder Stores near you http://factorybuilder.wpengine.com/contact-us/locations/ and we’ll get you set up with the perfect vent hood for your kitchen!
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