Basic Ventilation

So you have your heart set on the pro range range or you cook a lot. Now you need a vent for one reason. You want the smoke, odor, grease and heat outside your house. Ventilation has become more important in a kitchen plan especially with the advent of high powered ranges.

Buying the proper vent is not hard to do as there are only four characteristics of good ventilation: Capture area, CFM or blower speed, Duct size and Duct run or length of ducting.

Lets look at each.

Capture area is the size of the venting area of the hood. Typically, especially on the more powerful ranges, the hood depth should be at least 24 inches deep. Most renovators will buy a sleek, shallow hood or build out the cabinet as the vent and will beef up the CFM of the hood as a countermeasure. Does not work. Simply, smoke frome the range is captured first by the hood and then blown and filtered out by the motor. The smoke, heat and grease will not be captured by a shallow hood on a Professional range

CFM is short for Cubic Foot per Minute or how many cubes of air are blown out per minute by the motor. Blower speed is a shorter description. Your typical hood and over the range microwave are about 310 CFM. You can buy blowers as high as 1500 CFM residentially. If you cook a lot especially wok cooking or frying, the greater the CFM on the hood should be. On a pro range with a grill or griddle 900 minimum on a 36 inch and 1200 minimum on a 48 inch. There seems to be an on going argument about inside versus outside blower. I prefer the blower inside. It is easier to service, and more aesthetic as you will not have to look at a huge blower outside of your house.

Four inch duct is for dryers. A dryer exhausts at 180 CFM without smoke or grease. Your stove duct should be at least 6 inch and on professional cooking up to 10 inch. If you constrict the duct, then less smoke is exhausted to the outside and more will stay in your house.


I probably could have included duct runs in the previous paragraph. It is, however, the biggest venting mistake. Each time the duct is bended, the efficiency will be curtailed. The best way to vent is straight up, because smoke travels this way naturally or straight back without bends in the ducting. My favorite analogy is drinking a with a straw that is bent two or three ways. Doesn't work too well.

The last word on ventilation is ductless or non-vented installation. If you are unable to duct outside, having a hood with a filter is better than nothing. The smoke and grease will be filtered, but the heat will be recirculated back into the kitchen

Tomorrow, we will blog different styles of vents. There really are some beautiful styles of hoods in the market.