It’s time we take venting your stove seriously.
A simple Google search of, “Is your gas stove harmful?” will produce some shocking answers, like your gas stove may be killing you.
The reality is, the air inside our home is worse than the outdoors. Interior air pollution and sick building syndrome are caused in part by poor ventilation.
In this article, you’ll learn how to plan your ventilation properly, and then I’ll show you the five kitchen vents types you should never buy, especially if you cook.
Table of Contents
Ventilation Basics
Well designed ventilation can be divided into 4 parts.
CFM
CFM means, literally, cubic feet per minute, or the amount of cubes of air expelled by your motor every minute.
For example, a 600 CFM exhaust is 600 cubes per minute. A 1200 CFM motor can exhaust the equivalent of a small room of air per minute, so you need to make up or return that air.
Capture Area
Capture is the size of the vent and the one variable all bad vents we will mention lack.
Smoke is not immediately evacuated from your home when you stir fry, grill, or even burn your food on your cooktop. It’s captured by the hood and then the motor extracts the air from your home.
Captures have become more important over the last few years, since the most powerful burners are now at the front of your range or stove top.
A shallow hood or worse as you’ll see, will have smoke below pass it even with a high CFM motor.
Duct / Vent Run Length
Short vent runs are the most effective, either straight up or back. Longer duct runs are less effective, especially with transitions.
Transitions or elbows in the vent slow the static flow of the air. Some of the reason your cooking should be against the wall, not in an island, venting is much easier.
Duct Size
I remember a developer once asked me why the vents wouldn’t work in his projects. The reason, his contractor used four inch dryer duct.
The specs call for an 8 inch steel, not 4 inch vinyl. New construction, 8-10 inch round duct is the preferred size and it’s simple to do.
Kitchen Vents Types to Avoid
Let’s look at how not to vent. We’ll show you four hoods you need to cross off your list.
Downdrafts
Placing a downdraft in your island will look pretty and allow you to entertain your guests while cooking, except it won’t work if you cook.
Downdrafts, have no capture and reverse the airflow. They are vented longer with at least one transition.
They’re also placed in the back while the hotter burners are at the front. You look at design magazines and see pictures and understand people are sacrificing performance for what is considered better design.
If you need to place cooking in an island, buy an overhead hood to vent properly. Place your cooking against a wall where it will be vented easier.
Slide-out Hoods
Why are these marketed as “high end”? They should have been discontinued in the 1980s. A slide out hood is a piece of glass sliding out from a cabinet.
That piece of glass does not cover the burners or provide any capture area for heat, grease or smoke if you actually cook.
You do lose the cabinet because of the blower, so instead, install a hood that will actually work.
Over-the-range Microwave
The over the range microwaves were perhaps my favorite appliance when introduced in the early 1990s.
You can centralize your cooking with a range underneath. When appliances were promotional, the over-the-range microwave was often free with other purchases.
However, stoves have changed from 12,000 BTU max output in the 1990s to over 21,000 BTU max today.
Most ranges have, now, two power burners located in the front, so the average range is increased markedly while the over-the-range is the same design as 30 years ago and it will not vent for two factors.
The CFM is still only 300 to 360. It’s not enough to vent if you cook.
I haven’t asked the question how much CFM you do need. However, if you cook, more is better.
Forget the old equations of 10 CFM per BTU output.
I would consider a larger blower because it doesn’t cost that much more for better exhaust. If you cook, place a hood over the range and locate your microwave elsewhere, like under a cabinet, or built-in in a drawer, or even sit on a counter.
Wood Hoods
You should consider a wood hood for a different design detail than stainless steel. However, many people sacrifice function for form by blending it with the cabinet depths to 21 inches.
Capture becomes a problem at 21 inches or less since the burners extend further. Also, many of these wood hoods are underpowered at 300-500 CFM. Just make sure the blower has the right CFM and extend your wood hood to 24 inches.
Ceiling Blowers
Many years ago I lived in an apartment in Cambridge. They placed an oversized bathroom vent on the ceiling over the stove so they could have windows unobstructed by a hood behind it.
The bath vent was 400 CFM which was higher output at the time. However, the grime on the ceiling was almost palpable.
Flash forward to today and now these blowers are big at 43 inches wide and powerful at 1200 CFM.
However, I am unsure about the capture. Most regular hoods recommend 30-36 inches over the cooking surface for efficiency and capturing smoke and heat.
If you place the ceiling blower high enough, the smoke could dissipate or remain in your home, we have to test in the showroom.
However, a regular range hood with better capture is probably a better idea.
Takeaways
First you should know the internal air quality is a problem in many homes due to poor ventilation.
Plan your ventilation right with the right CFM and capture and then vent properly.
After that, do not buy a downdraft, slider hood, or over-the-range microwave. Wood hoods need to be planned.
Once you know venting is not that hard to execute.
Unfortunately, we all know someone who’s been talked into buying the wrong appliance or venting the wrong way. Don’t let that happen to you.