A range hood is more than just a mechanical mechanism for removing cooking odors, it is something akin to a life-support system for your kitchen.

The days of ventilating your kitchen by opening a window are long gone. Today’s houses are being built increasingly airtight, all have central air, and windows remain closed most of the year, making mechanical ventilation a necessity. An effective range hood is needed to exhaust excess heat, humidity, cooking odors and fumes produced in the kitchen. The best models also have grease traps build in to help keep the kitchen clean. These features all help to make the range an integral part of the home’s indoor air-quality system, helping to improve safety and hygiene.

There are a wide variety of options available in terms of style, function and capacity. Here are a few things you need to know when selecting the right model for your home.

Recirculating vs. Outdoor-venting

The most effective ventilation systems exhaust air outside. You’ll find the lower end units are recirculating hoods, that don’t have outdoor venting, but do filter grease and odors from the air. These recirculating units however don’t remove humidity or chemical pollutants. They are often more noisy than outdoor venting units.

If you are forced to use a recirculating unit make sure you get a model with a good aluminum-screen grease trap that you can put in the dishwasher.

The best choice is always an outdoor vented hood, but for it to be effective, proper installation is essential. Too narrow a duct will limit the hoods performance, while a duct that is too wide will reduce air velocity resulting in grease build up along the walls of the duct. This becomes a fire risk. The duct should also follow as direct a path as possible to the outside avoiding sharp angles. Also never use corrugated pipe, as grease builds up in the grooves and increases the fire risk.

Choice of Canopy

When selecting a hood don’t just go for what is visually appealing but make sure that it is sized correctly. At a minimum the canopy needs to be at least as wide as the cooktop and 18 in. deep. It should preferably be 24 to 27 in. deep. The depth is more important than width and the hood should cover all the back burners and three quarters of the front burners.

The canopy should be installed 18 – 30 in. above the cooktop. Some people like to install it higher than 30 in. to show off more of the kitchen’s backsplash, but remember if you go higher than 30 in. you’re going to need a stronger fan.

Fan Sizes

The next consideration is how powerful the fan should be. In other words we have to consider how many cubic feet of air per minute can the hood’s fan exhaust. The industry recommendation is that the fans capacity should be 40 -50 cfm per linear foot of range, this is about 120 – 150 cfm for a standard unit. Engineers in the field recommend at least 160 cfm.

When installing a hood it’s always a good idea to follow the manufacturers recommendations. These recommendations are based on a combination of factors including the stove’s heat output, location of the hood, length of the duct between the hood and the outdoor exhaust outlet. Bigger is not always better.

Another factor to consider is the fan motor. Some motors are housed in the hood, while others may be in the duct work or located outside. Hood mounted fan motors are the loudest while the quietest location would be to mount the fan motor outside. This is not always practical due to weather conditions. When the fan motor is mounted in the hood, sound characteristics become an important consideration. If the fan motor is too loud the tendency is to turn it off, thereby defeating the object.

Overhead or Down Draft

The standard configuration is an overhead hood placed directly over the cooktop. Sometimes the stoves location (such as a kitchen island) requires a downdraft model or a freestanding hood.  Hoods placed over the range on a kitchen island need to be considerably larger than others to compensate for air cross currents.

There is a huge variety of hoods available, shop around and find the perfect one that will not only quietly remove heat moisture and odors but that also looks great.