A hurricane is a powerful tropical storm that measures several hundred miles in diameter. Hurricanes have two main parts. The first is the eye of the hurricane, which is a calm area in the center of the storm. Usually, the eye of a hurricane measures about 20 miles in diameter, and has very few clouds. The second part is the wall of clouds that surrounds the calm eye. This is where the hurricane's strongest winds and heaviest rain occur.
A quality kitchen ventilation system plays a significant role in the indoor air quality of the home, drawing stale air filled with grease, odors, and moisture out of the room. A range hood’s noise level, power, and efficiency are often overlooked, but décor choices and technology have combined to bring good ventilation to the forefront of kitchen design.
Hoods and Ventilation
Range hoods are crafted from a variety of materials including copper, stainless steel, natural woods, ceramic, and tile. Finishes, shapes, and models range from stark modern to faux French, provinicial, and country. Trims and finishes can be customized, so it’s not unusual for homeowners to have custom hoods installed and purchase the ventilation system separately as a hood insert.
A ventilation system or range hood can cost anywhere from a few hundred dollars to thousands. Abbaka, a Swedish company, has one range hood system that sells for $10,000. Some high-end range hoods feature smart technology that can turn them on automatically when heat is detected, and others that feature auto shut-offs, alerts when the filters need to be cleaned, or 24-hour modes that keep the hood running at a low-power output to refresh household air.
Ventilation Ducts and Filters
Good kitchen ventilation should draw out stale air, remove grease and odors, and reduce moisture. A properly powered and sized range hood is placed over the cooktop to draw in stale cooking air and fresh air from the the rest of the house. “The hood creates an air current, and draws from wherever the air is coming from,” says Matt Avery, Sales and Marketing Coordinator for Faber, an Italian range hood company. “Any smoke, moisture, or bad air in the kitchen or adjacent rooms should get pulled into the hood and, ideally, exhausted to outside the home.”
Most kitchen ventilation products are wall or ceiling-mounted updraft systems concealed in a hood. An updraft system draws air and moisture up into the hood and exhausts it outside via ducts and vents. A ductless or recirculating updraft system draws air through a grease filter and often a charcoal filter to eliminate odors before recycling it back into the room. These recirculating hood systems are placed over the cooktop and are effective at catching grease and odors but inefficient at removing moisture from the air.
Downdraft, or proximity, systems do not involve overhead hoods. They draw air down into the system, which is installed in the cooktop or an adjacent cooking surface. Downdraft systems are always exhausted or ducted.
While other appliances like microwaves and ovens have venting needs, they do not usually require a separate ventilation system. Ovens built below a cooktop sometimes vent through one of the burners, allowing air to rise into the hood or be captured by a downdraft. Wall-mounted ovens will often vent to the front of the appliance and into the general room air.
Grease filters may be mesh or baffled and should be removable for easy cleaning. Mesh filters are standard and have multiple layers of mesh to maximize grease-catching capacity. A baffle filter is commonly found in restaurants and traps grease in shaped metal channels. “Baffle filters are more efficient,” says Avery, “and they tend to better complement the style of a hood.”
Sizing for Safe Ventilation
Ventilation systems measure power in cubic feet per minute or CFM. The higher the CFM rating, the more air the system will move. Range hoods should extend beyond the edge of the cooktop and have a power matched to their size. Peter Solerno, a kitchen designer in New Jersey, recommends at least an 800 CFM system for any 36” commercial stove. “A 48-inch unit would probably require as much as 1000-1200 CFM,” he says.
More powerful systems draw a significant amount of air and may require a make-up air system to protect the home from negative pressure. Negative pressure occurs when a strong air draw, like ventilation, calls for more intake than the household air can provide, forcing it to pull against other venting appliances like furnaces and hot-water heaters. This tug of war can cause those appliances to backdraft, bringing noxious fumes and dangerous byproducts of combustion, like carbon monoxide, into the home. It is important that the ventilation unit not be too powerful for the home without a make-up air system to support it. A kitchen ventilation specialist can do the math and make appropriate recommendations.
Controlling Ventilation Noise
It is a common misconception that the noise from a range hood or ventilation system is caused by the fan. “The noise is mainly from the sound of the air being drawn through the filters,” says Avery. The sound level of a ventilation system, measured in sones, is one of the reasons why homeowners do not regularly use their ventilation systems. To avoid the noise, homeowners sometimes choose remote blowers that locate the motor on the roof or outside the home. However, remote blowers are usually more powerful and draw more air through the filters, which can cause even greater noise.
Homeowners looking for quieter models should look at the sone rating, which is unique to the ventilation industry. A sone rating of about 5.5 or less is desirable. For comparison’s sake, a quiet refrigerator produces a sound equivalent of about 3 sones.
Credit: Renovate Your World