Why is a range hood louder than its sone rating?
Because the sone rating a maker puts on the box is usually from a slow speed, and at full cooking speed the quiet-marketed hoods we checked were certified at 5 to 13 sones. Look at how quiet hoods are marketed, then look them up in HVI's certified directory:
Broan advertised the Elite Alta at "less than 0.3 sones" at normal speed. It is certified at 7 sones on high.
Best advertises its HBN5 insert at "less than 0.3 sones at low speed." It is certified at 11.5 sones at full power.
Zephyr's spec sheet lists the Tempest I at 1 to 6 sones. HVI certifies its high speed at 10 to 11.5.
None of those low figures is false. They are just from the wrong speed. ENERGY STAR measures range hood noise at "working speed" (the first speed at or above 100 CFM), which gives every maker an official low-speed number to put on the box.
Zephyr prints a range like the Tempest's for nearly every hood it sells, and our Zephyr range hood sones page sets each one beside HVI's certified high-speed figure wherever HVI lists the hood.
That is why this guide ranks on high-speed ratings. It is the only fair way to compare how loud a hood is when it's doing its job.
If your kitchen opens onto a living or dining area, the open-plan section below goes a step further and reads the sones at the step a typical cooktop actually needs.
How do you read range hood noise ratings?
Find the high-speed sones, paired with the CFM. A sone rating means nothing without the airflow it was measured at. "4 sones at 470 CFM" is a useful figure. "As low as 1 sone" is not.
Remember sones are linear. An 8-sone hood sounds twice as loud as a 4-sone hood, and a 12-sone hood three times as loud. The gap between our top pick and a typical quiet-marketed hood on high is bigger than it looks.
Prefer HVI-certified ratings
HVI tests hoods independently, and it warns plainly that inflated performance ratings are common for hoods that are not certified. Several direct-to-consumer brands (Hauslane, Proline, KOBE, CIARRA) do not appear in HVI's directory, so their figures are self-reported.
Proline's page for its PLJW 185 claims 4 sones at 600 CFM on max speed, while Proline's own blog gives five sones for the same hood. More under-cabinet hoods with a maker figure are on the under-cabinet page.
Watch out for "equivalent CFM." Some brands quote an "equivalent" airflow credited to a filter design rather than a measured figure. FOTILE's Pixie Air advertises 850 equivalent CFM and is certified at 600; Hauslane quotes 860 equivalent CFM against 500 in the lab for its UC-PS18. Compare certified CFM only.
How much CFM does a range hood need?
By HVI's formula, a typical 30- or 36-inch wall-mounted hood over an electric or induction cooktop needs 250 to 300 CFM. More airflow means more noise at the top speed, so buy what your cooking needs rather than the biggest number available.
- Wall-mounted hoods: HVI recommends 100 CFM per linear foot of cooktop, with 40 as a minimum. A 30-inch range needs about 250 CFM.
- Island hoods: 150 CFM per linear foot, with 50 as a minimum.
- High-output gas ranges: Broan and Viking recommend at least 1 CFM per 100 BTU of total burner output. A 45,000 BTU range works out to about 450 CFM.
The 1,000-plus CFM hoods are for serious gas burners, and every one we checked is loud at the top.
If the hood is a custom one built into cabinetry, our guide to range hood inserts and power packs sorts the certified inserts into airflow bands, because across them the high-speed rating climbs with the high-speed airflow.
For a chimney hood on an open wall, our guide to the quietest wall-mount range hoods reads each certified pyramid, box and glass canopy hood at the step a 30 or 36-inch cooktop needs; FOTILE's EMS9026 is certified at 2 sones at 360 CFM on its lowest step.
An island needs that extra airflow because it has no wall to help contain the smoke. Our guide to the quietest island range hoods ranks every island hood we could match in the HVI directory, and reads off the certified figure at the step a 36-inch island needs.
If you are weighing an over-the-range microwave instead of a hood, its vent fan is rated in sones the same way. Our microwave guide covers what those certified ratings look like at high speed and at working speed.
Which range hood speed matters in an open-plan kitchen?
In an open-plan kitchen, the range hood speed that matters is the first one with enough airflow for your cooktop: 250 CFM for a 30-inch cooktop and 300 CFM for a 36-inch one, by HVI's rule above.
The figure that counts is the sone rating at that step, and whether that figure is certified.
When the kitchen opens onto the sofa and the dining table, the hood runs in the middle of the conversation.
For our picks, that step is:
FOTILE Pixie Air UQG3002.
Speed 2, certified at 2.5 sones at 370 CFM through a 7-inch round duct and 4 sones at 370 CFM with rectangular 3-1/4 x 10-inch ducting. Speed 1 is certified at 1.2 sones at 240 CFM, just under the 30-inch figure.
Bosch 800 Series HUI80553UC.
High, certified at 5 sones at 380 CFM, because Bosch publishes 0.7 sone at 180 CFM and nothing in between.
Broan Glacier GLA3364SS.
High, certified at 6.5 to 7.5 sones at 380 to 420 CFM depending on the duct. Medium is 4.0 to 4.5 sones at 280 CFM on Broan's spec sheet, not certified and just short of a 36-inch cooktop's 300 CFM.
Best HBN5 HBN536912SS.
For a 60,000 BTU gas range, about 600 CFM by the 1 CFM per 100 BTU rule, speed 5, listed at 4.5 sones at 730 CFM on Best's spec sheet and not certified: a bigger blower on a middle step, the case Best's own buying guide makes.
The lowest certified figure we found at 300 CFM or more is not among the picks above: FOTILE's 36-inch EMS9026 wall chimney hood is certified at 2 sones at 360 CFM on its lowest step, 4 sones at 450 CFM on high and 7 sones at 560 CFM on boost, through a 6-inch round duct, so its first step alone covers a 36-inch cooktop.
An island cooktop needs about 450 CFM at 36 inches by HVI's 150 CFM per foot, which means a higher step; Best's ICB3I36SBS island hood is certified at 1.5 sones at 210 CFM on normal speed and 11.5 sones at 580 CFM on high, with nothing published for the two speeds between.
Two features count for more from the sofa than at the stove.
Automatic modes raise the speed on their own: Broan's SmartSense Auto on the Glacier follows cooktop heat, Bosch's Home Connect lets the 800 Series insert match a Bosch induction cooktop, and Best's SmartSense Pro and Heat Sentry on the HBN5 inserts respond to heat, humidity and VOCs.
Delayed shutoff keeps the hood running after you sit down to eat: 5, 15 or 30 minutes on the Pixie Air, 2 on the EMS9026 and 5 on the ICB3.
Does the duct change how loud a range hood is?
Yes, the same range hood can be quieter or louder depending on the duct behind it. HVI certifies FOTILE's Pixie Air at 4 sones at 470 CFM through a 7-inch round duct, but 5.5 sones at 460 CFM if the duct is 3-1/4 x 10-inch rectangular. On boost, the gap is 6 sones against 8.
The Pixie Air hangs under the cabinets, and our guide to the quietest under-cabinet range hoods ranks it with the other 30 and 36-inch hoods that sit at face height, including the duct each figure comes from.
HVI's general advice is to use smooth metal duct, match the size of the hood's outlet, and keep the run short and straight. Every elbow and every step down in size makes a hood work harder, and a hood working harder is louder.
Are inline and remote blowers quieter?
Yes, inline and remote blowers are the quietest arrangement for a big hood, because they move the motor out of the kitchen entirely.
An inline blower sits in the ductwork, and a remote or external blower mounts on the roof or an outside wall. You still hear air moving at the hood, but not the motor.
We would love to tell you how much quieter that is. Nobody publishes it. HVI lists remote blowers with airflow ratings only, and Zephyr marks its external and inline blowers' sones as not applicable.
California's energy code even exempts remotely mounted fans from its sound limits when there are at least 4 feet of duct between the fan and the room.
If you are spending on a pro-style hood, a remote blower is the upgrade to ask your installer about. Just know that the benefit can't be compared on paper.
Downdraft vents have the same gap: our downdraft guide found no sone figure for the remote blowers sold for them either, and found that the direction the duct leaves the blower changes the certified rating.
Are ductless range hoods effective?
No, not as ventilation: HVI says plainly that recirculating range hoods provide no actual ventilation, though they are easy to install. They filter the air and blow it back into the kitchen, and Consumer Reports found the only recirculating hood it tested was by far the worst.
If there is any way to vent outside, do it. Most of the hoods here can recirculate with a kit, but none of them are at their best that way.
When does a range hood need make-up air?
The International Residential Code requires make-up air for exhaust systems over 400 CFM when the home has fuel-burning appliances that are neither direct-vent nor mechanically vented.
A powerful hood pulls a lot of air out of your house, and that air has to come back from somewhere.
Your local code may differ, so check with your building department before you buy a high-CFM hood.
What are the most common range hood buying mistakes?
The common ones are comparing low-speed sones, buying on maximum CFM, oversizing, skimping on the duct and assuming ductless is the quiet option.
Comparing low-speed sones
The low-speed number is the one on the box and the one that matters least.
Another mistake is buying on "max CFM." Broan explains that maximum blower CFM is measured with no duct attached, and equivalent CFM is not measured at all. Compare certified CFM at the pressure HVI uses.
Oversizing
A hood running at 1,200 CFM over an electric cooktop is loud for no benefit, and may trigger a make-up air requirement.
Skimping on the duct
Even a hood certified as quiet gets loud when its duct is long, narrow or kinked.
Assuming ductless is the quiet option
It is mostly the no-ventilation option.
Whether 4 sones at full power is quiet enough for your kitchen depends on what else the room is used for.
If you are replacing a hood because it has grown louder, rule out a fixable cause first, and remember that a new hood on the same kinked duct will not be quiet either.
