Kitchen Ventilation – Blowers, Ducting, Filters and Lighting

Blower Systems

source: Jenn-Air

One of the most important components of your vent hood is the blower or fan system. Larger blowers will have larger CFM capacities, but also tend to be noisier. Noise levels are measured in sones. Blower sytems tend to have sone ratings bewteen 2 and 9 with 9 being the loudest.

There are three options when it comes blowers:

• Internal Blowers are mounted inside the hood and usually have a lower CFM rating. These tend to be the noisiest but they don’t muck up the exterior of your home.

• External Blowers are mounted outside your home usually on a wall or on the roof, making them one of the quieter options. They tend to have more power - 1,000 CFMs or higher which makes them a great choice for professional style ranges & cooktops.

• In-Line Blowers are mounted within the ductwork between the hood and the outside vent. They are typically used as a "booster" for homes with longer than average ductwork. They are also usually used with downdraft systems or may be used on their own.

Fans located in these blower systems typically come in two designs: a traditional rotary design (blades) or centrifugal (barrel/wheel-shaped). Centrifugal fans are quieter and more efficient. Some higher-end vent hoods require you to purchase the blower system separately.

Look for blowers with multiple or variable fan speeds so you can adjust your ventilation needs to the type of cooking you are doing.

Ducting Requirements

Most vent hoods require ducting with the exception of some duct-less recirculating systems. The effectiveness of your hood is directly related to the duct work you install so you should never compromise when it comes to the recommended duct size and the angles of installation.

Never use a smaller duct size than what is recommended. Typically the more CFMs the blower has the larger the duct size needed. A single 100 CFM blower may only require a 6” diameter duct while a larger 1200 CFM blower may need a 12” diameter duct.

Keep duct runs short (under 30 feet total) and minimize bends to maximize airflow (limit to two or three of 45 degrees). When possible, locate your range or cooktop on an outside wall since the ducting length to the outside will be shorter and therefore more efficient.

Smooth metal ducting is recommended over flexible metal ducting – never use plastic ducting! And a roof cap outside the house will prevent any back drafts especially in colder climates.

Duct work should always be vented to the outside - NEVER into an attic, chimney or other enclosed space because of the potential fire hazard.

Filters

source: Jenn-Air

Filters are an important part of your vent hood because they trap oil and grease from cooking. Charcoal filters used in recirculating hoods also capture odors.

You'll need to know what kind of filter your hood is fitted with. Small hoods are usually fitted with removable screen filters that are dishwasher-safe, making cleanup easy. Larger hoods are fitted with baffle filters that collect grease and other particles into a receptacle that should be cleaned out on a regular basis.

Charcoal filters cannot be cleaned so they will have to be replaced. To keep your vent hood working properly its important to clean or replace the filters every one to three months or per the manufacturer’s recommendation.

Lighting

source: Jenn-Air

Most standard vent hoods have built in lighting. A good range hood will provide enough light for you to see your range or cooktop clearly. Some models use only a single 40 watt bulb, which many cooks don't find adequate, while some use two bulbs which is certainly better than one.

Many of the more expensive range hoods provide much better light using halogen lamps with dimming options or fluorescent bulbs, with the number of bulbs related to the width of the hood. Heat lamps can be added depending on the model you choose.

Learn more: Clearing the Air – A Guide to Kitchen Ventilation