Give Your Kitchen a
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Give Your Kitchen a
A primer on proper ventilation
A range hood is more than a mechanism
to remove cooking odors; it’s an important component in a
kitchen’s decor. A sleek, well-designed model makes a bold statement: that the resident chef is no slouch. But beyond putting on
culinary airs, a range hood is something akin to a life-support system for your kitchen.
In days gone by, ventilating the kitchen meant opening a window.
Today, however, houses are being built increasingly airtight, central air
is ubiquitous, and windows remain closed most of the year, making
mechanical ventilation a necessity. An effective range hood will exhaust
excess heat, humidity, cooking odors and fumes from household chemicals.
The best models will also trap grease to help keep the kitchen clean. All these
features make the range hood an integral part of a home’s indoor air-quality
system, improving safety and hygiene.
Modern range hoods offer a wide variety of options in terms of style, function
and capacity. Here’s what you need to know when selecting the right model for
your kitchen.
Recirculating vs. outdoor-venting
An effective ventilation system exhausts air outside. Low-end recirculating hoods, which
do not have outdoor venting, may filter grease and odors, but they won’t remove humidity and chemical pollutants. Many also make a lot of noise and do little to trap odors and
grease. “If an outside-ducted range hood is impractical, consider supplementing the range
hood with a central ventilator similar to a bath fan that does vent to the outdoors,” advises
James Lyon, a professional engineer with Newport Partners. Keep in mind that building codes
require any fan within a 45-degree angle of the cooktop to have a grease trap.
If you must use a recirculating hood, look for a model with a good aluminum-screen grease trap
that you can put in the dishwasher and the largest charcoal-bed filter available for smoke and odors.
Some models have a combination of baffle and mesh grease filters. The baffles work well when the fan
runs at high speed; the mesh is for low speed.
An outdoor-vented range hood is always the best choice, but for it to be effective, proper installation
is essential (see “Kitchen Vent-Hood Installation,” opposite). A too-narrow duct will detract from the
hood’s performance; a duct that is too wide may reduce air velocity, resulting in grease deposits along the
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pipe, says Lyon. The duct should
match the hood’s port size and follow
a direct path to the exterior, avoiding
sharp angles. Never use corrugated
pipe; grease will build up in the
grooves and could catch on fire.
Canopy choices
When choosing a hood, you’ll need
to select the right size canopy (the visible portion of the hood that captures
air). The canopy should be as wide as
the cooktop and at least 18 in. deep
but preferably 24 to 27 in. Extra depth
Duct Options
Choose the one that works best for your house:
A Through the roof using round duct (most often used in one-story houses)
B Side of house through upper cabinet using round duct
C Side of house through back of hood using rectangular duct
Strap duct with metal
tape when using sections
longer than 3 ft.
When shopping for ventilation
fans, keep in mind these essential factors:
• Air movement: measured in
cubic feet per minute (cfm)
• Energy: consumed in watts
• Noise: measured in sones
(one sone is equal to the sound of
leaves rustling on a quiet night)
• Duct size: the diameter of
the exhaust port
First determine the airmovement capacity you need;
then compare models’ energy
consumption, sones and duct
size. Here are some tips to consider when evaluating your options:
• A more efficient fan may cost
more, but it will often pay for itself
in a few months of operation.
• A high-quality kitchen fan
will operate at .3 sones at 150
cfm and at up to 2 sones at high
speed — quiet enough to allow
casual conversation even at the
highest setting. The quietest
and most efficient motors run
on DC current.
• Duct size influences efficiency, performance and quiet
operation. Air moves through a
larger duct at a lower, quieter
volume and produces less static
pressure that can choke off fan
function. Older units often had
ducts as narrow as 3 in.; nowadays
the minimum size is 4 in. for bathrooms and 6 in. for kitchens — a
good reason to replace old ducts
when upgrading a fan. — FPR
Duct terminates on
an exterior wall or
the roof, away from
windows, flammable surfaces or
eave vents that
can draw cooking
fumes into the attic
6- to 8-in. round
exhaust duct
Caulk duct to wall/ceiling
(or cabinet) at interior
Galvanized metal
sidewall cap with
back-draft flap;
caulk wall-cap
termination to duct
Foil tape tightly covers
all metal duct joints
Canopy width:
equal to cooktop width
Hood canopy
Canopy height:
18 to 30 in.
above cooktop
Canopy depth:
hood should cover all
rear burners and at
least three-quarters of
the front burners;
minimum 18 in. deep,
preferably 24 to 27 in.
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If you can’t exhaust the kitchen fan through ducts to
the outdoors, choose a recirculating fan with the best
filters. A nonducted kitchen fan should include an
aluminum-screen grease trap that you can put in the
dishwasher and a charcoal-bed filter for smoke and
odors. Some range hoods, such as the Best UP27
(top), can be connected to an accessory recirculating
kit (right) that features additional filters. — FPR
matters more than width, says Brian Wellnitz, a kitchen
ventilation spokesman for Broan. “The hood should cover
all the back burners and at least three-quarters of the front
burners,” he says. The canopy should be 18 to 30 in. above
the cooktop. Some kitchen designers like to add a few
inches to show off backsplash tile or provide a more comfortable view of the stove for a tall cook, but if you set the
hood higher than 30 in., you will need a stronger fan.
Fan sizes
For a large, multiburner, commercial-style range, you
should always follow the stove manufacturer’s recommendations about fan size. The manufacturer bases recommendations on a combination of factors including the stove’s
“A fan’s functional capacity
is often much lower than the
manufacturer’s rating”
Steve Easley, building science consultant
The next consideration is horsepower. In the world of
hoods, brawn is measured by how many cubic feet of air
per minute (cfm) the hood’s fan can exhaust. The Home
Ventilation Institute (a manufacturers’ trade association)
recommends a range hood with a fan capacity of 40 to
50 cfm per linear foot of range (about 120 to 150 cfm for
a standard 30-in. unit), but the engineers we spoke to
recommend a minimum of 160 cfm. “A fan’s functional
capacity is often much lower than the manufacturer’s
rating,” explains Steve Easley, a building science consultant at S. Easley & Associates Inc.
Recirculating kit
heat output, the location of the hood and the length of the
duct between the hood and the outdoor exhaust outlet.
Keep in mind that bigger isn’t always better. “Bigger
fans consume more electricity, and they can create a
dangerous condition
called back drafting,”
explains Easley. This
To learn more about installing
a bathroom vent fan, go to
occurs when the
tion of a powerful fan
and click on WEB EXTRAS.
creates negative pres-
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Today’s hoods offer amenities that go beyond basic
ventilation. Look for a model with bright halogen bulbs for
good cooktop visibility, easy-to-remove-and-clean soffit grills
and matching splash plates to cover the exposed cabinet sides and
backsplash. Some hoods come with a removable liner that you
can place in the dishwasher along with the grease grill. If a hood
draws too much air for the application, most manufacturers provide a reducer you can install. Airflow regulators limit high-airflow
hoods to less than 300 cfm so they comply with most local codes
without the need for makeup air. Some hoods, such as Broan’s
QP3 (right), come with an optional remote control. — FPR
rior wall or in line on a duct (see “Fan Basics,” p. 35). When
the motor is housed in the hood or within earshot, the
sound characteristics of the fan become an important consideration because loud fans are irritating and we tend to
shut them off. The quietest location for the fan motor is
outside, but harsh weather can make this impractical. Look
for a fan with a quiet motor — a good indicator of the quality and efficiency of the fan, as quieter motors require better components and run more efficiently.
Overhead or downdraft
You’ll get better ventilation from a dedicated vent hood
than from an over-the-range (OTR) microwave with a
built-in vent fan. But if space is limited, an OTR
microwave that is ducted to the outdoors may be the
solution, especially if you don’t do a lot of high-heat
cooking on your stove. Look for a model, such as the
GE Profile Advantum 120, that features washable filters
and a fan that moves at least 300 cfm to help compensate for the small capture area. — FPR
sure in the home and interferes with the exhaust ventilation of combustion devices. (Safety note: When installing
a high-capacity exhaust system of 900 cfm or more, hire an
energy-audit contractor to verify that the fan is not creating negative pressure. Experts recommend coupling any
large range hood with a hard-wired carbon-monoxide
detector as a precaution.)
Fan motors may be housed within the fan, on an exte-
Because hot air rises, the standard configuration of an overhead hood placed against a wall typically works best. But
sometimes the stove’s location (for example, in a kitchen
island) requires a downdraft model or a freestanding hood.
These hoods draw significantly more air to compensate for
cross currents. When choosing a hood that will be located
over a kitchen island, you should multiply the cfm requirement of a conventional hood by 1.5, says the Heating and
Ventilation Institute.
Given the variety of options available, you can find the
perfect range hood for your kitchen. Shop around for a
model that will quietly remove moisture and indoor pollutants, light up your work area, operate energy-efficiently
and look great. u
Handyman Club life member Fernando Pagés Ruiz is a homebuilder and remodeler with 30 years’ experience and the author
of Affordable Remodel: How to How to Get Custom Results
on Any Budget (The Taunton Press, 2007).
For online information, go to and click on WEB EXTRAS.
Broan (QP3 range hood),
Best Range Hoods (UP27 range hood)
GE (Profile Advantum 120 microwave)
Home Ventilating Institute
(847) 416-7257,
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