A downdraft vent is the hood you buy when you do not want a hood. It hides flush with the counter behind an island cooktop, rises when you press a button, and pulls the smoke down through the cabinet and out under the floor. The sight lines stay open, the ceiling stays clear, and the blower sits down at knee height instead of beside your ear. On paper that sounds like the quiet choice.
This guide checks that assumption against the certified figures. We took every downdraft in the Home Ventilating Institute (HVI) directory, matched each one to a model on its maker's site, and ranked them on certified sones at high speed, because high is the speed a downdraft needs to cover a cooktop. We then read each maker's duct and blower tables, which turn out to matter more for a downdraft than for any overhead hood. For the room as a whole, the fridge and dishwasher included, see our page on planning a quiet open-plan kitchen.
Our picks are listed above, with full specifications for each.
How we ranked them
Picks are in order of their HVI-certified rating at high speed, measured at 0.1 inch of static pressure, with the duct and discharge direction the directory lists. HVI files these under Downdraft Kitchen Ventilators, and several entries are listed as a blower "with compatible downdraft intake" rather than by the hood's own model number, so we matched each blower to the downdraft its maker names for it: Zephyr's DBI-600A to the Lift, Best's PF6 to the D49M, the BSH blowers to the Bosch and Thermador units. Where a maker publishes figures for other duct directions, we quote them and say whether the directory carries them.
Sones are linear. 9 sones sounds twice as loud as 4.5, and 11 sounds about a quarter louder than 9. So the spread between our quietest pick at 8.5 and the Bosch and Thermador at 11 is real but not huge, and all of them are a long way from the 4 sones the quietest wall hoods manage. Decibels work differently, and there is no reliable way to convert one into the other, so we never do. Our explainer on sones vs decibels covers the units.
Why a downdraft runs on high
An overhead hood has gravity on its side: hot air rises into it. A downdraft has to pull that same rising plume sideways and down, from a vent that may be 7 to 18 inches above the burners. FOTILE, which sells no downdraft itself, puts it plainly in its guide to hood styles: downdraft hoods "are great for island cooktops or minimalist kitchens where preserving sightlines is a priority", but "their airflow tends to be less powerful than overhead options". Zephyr's own Lift manual tells owners to use the rear burners when cooking with tall pots or anything that makes a lot of smoke or steam, and to run the unit on high.
That is why the working-speed figures on the box do not describe your evenings. By Best's island rule of 150 CFM per foot of cooktop width, which it gives because an island has "no surrounding cabinets or walls to help contain rising smoke and cooking vapors", a 30-inch island cooktop needs about 375 CFM and a 36-inch one about 450. The certified working speeds here move 160 to 230 CFM. The certified high speeds move 440 to 500. On an island, the speed you will cook on is high, and the sone figure to compare is the high one.
Here is every downdraft in the directory we could match to a maker's page, with its HVI figures at working and high speed, 36-inch models unless noted:
- Zephyr Lift with DBI-600A: 1 sone at 180 CFM; 8.5 sones at 440 CFM.
- Best Cattura D49M with PF6: 0.9 sone at 190 CFM; 9 sones at 500 CFM.
- Zephyr Treviso (ZTV-E30AS, ZTV-E36AS): 2 sones at 200 CFM; 9.5 sones at 470 CFM, front or rear.
- Broan Elite (273003, 273603) and Zephyr Sorrento (DD1-E30AS, DD1-E36AS): 3 sones at 230 CFM; 10.5 sones at 500 CFM.
- Thermador UCVM36XS with VTD600P and Bosch HDD86052UC with DHG602DUC: 1.2 sones at 180 CFM; 11 sones at 450 CFM.
- Thermador UCVM30XS and Bosch HDD80052UC, 30-inch: 2 sones at 160 CFM; 12 sones at 380 CFM.
Two things stand out. The spread on high is narrow, 8.5 to 12 sones, and nothing here gets near the 4 sones that the quietest hoods in our quietest range hoods guide are certified at on high. And only one of these, the Cattura at 500 CFM, clears the 450 CFM a 36-inch island needs on a certified figure; the Lift falls 10 CFM short, and the 30-inch BSH units manage 380. For a 30-inch cooktop at 375 CFM, every unit here clears the line on high.
The number on the box
Downdrafts play the same low-speed trick as every other hood, and the gap is bigger here because the working speeds are so slow. Broan's product page lists "Sound Level (Sones) 3" for a unit certified at 10.5 sones on high. Best's page says "0.8 sones at normal speed with internal PF6 blower" for a unit certified at 0.9 on normal and 9 on high. Zephyr's Treviso sheet gives "2 - 6" sones for a unit certified at 9.5. And for the Lift and Sorrento, Zephyr prints "NA" in the sones column, so without the directory you would have no figure at all.
None of the low figures is false. They just describe 190 to 230 CFM, which is a simmer, not a sear. Our guide to range hoods for an open-plan kitchen walks through reading the sones at the step your cooktop actually needs for wall and under-cabinet hoods; for a downdraft, that step is almost always the top one.
Where the blower sits
This is the part of a downdraft that an overhead hood does not have, and it is where the quiet is supposed to come from. Bosch and Thermador list the motor location as external: the downdraft is an intake, and the 600 CFM blower is a separate box that bolts to it in the cabinet, sits in the duct run under the floor, or mounts outside. Best's PF6 "can be mounted directly to downdraft or mounted remotely", and Zephyr's DBI-600A is sold as an internal or in-line blower.
Every maker here also offers a bigger remote or inline blower. Zephyr pairs the Lift with a 1,000 CFM in-line PBN-1000A or external CBE-1000. Best offers the EB9 and EB15 exterior blowers and the ILB6, ILB9 and ILB11 in-line blowers for the D49M. Thermador sells 600 and 1,000 CFM versions of each, the VTR and VTI series, and its feature list says what they are for: "Remote or inline blowers to reduce noise, integral for top performance". Bosch offers the DHI1FZUC inline and DHR1FZUC remote.
What nobody publishes is how quiet that is. Thermador's blowers sheet prints a dash in the sones column for all four of its remote and inline blowers. Zephyr's blower sheet says NA for the PBN-1000A and CBE-1000. Bosch's spec sheet lists its own DHG602DUC in the inline position at 600 CFM and 0.2 inch with the sones marked N/A. Best's in-line and exterior blower sheets give airflow only. The remote blower is the right thing to ask your installer about for a big island, and it is the one configuration you cannot compare on paper. The same gap applies to overhead hoods, as our island range hoods guide found.
Discharge direction is a noise decision
Here is what the makers do publish, and it is the most useful thing in this guide. Because the blower bolts to the intake in different positions, the same downdraft can be certified at very different sones depending on which way the duct leaves it. Thermador's spec sheet for the UCVM36XS, headed HVI performance values, lists the unit with the VTD600P blower in all five directions:
- Front: 11.0 sones at 450 CFM on high, 1.2 sones at 180 CFM on working speed.
- Right: 11.0 sones at 400 CFM, 1.1 at 160.
- Rear: 9.5 sones at 400 CFM, 1.0 at 160.
- Left: 9.0 sones at 410 CFM, 0.9 at 160.
- Bottom: 8.5 sones at 420 CFM, 0.9 at 170.
Best's PF6 sheet does the same for the Cattura: 9.0 sones at 500 CFM to the front, 9.0 at 460 to the left, 8.0 at 430 to the rear, 9.0 at 450 below, and 11.0 at 440 to the right. The HVI directory itself carries only the front figure for both, so that is what we rank on, but the pattern is consistent across two makers: a duct that drops straight down through the floor or leaves the back of the cabinet is two to three sones quieter than one that turns forward or sideways. A downdraft with a floor beneath it that you can duct through is a quieter downdraft, and that is a decision to make with the cabinet maker before you choose the hood.
Broan's Eclipse spec sheet adds the other half of the duct story: the system "will operate most efficiently when the ductwork does not exceed 40 feet of equivalent duct", and its chart counts a 3-1/4 by 10-inch elbow as 8 feet and a transition to 6-inch round as 2. A downdraft duct that snakes under a floor and out a wall uses that budget quickly.
Cooktops with a built-in downdraft
We also looked for cooktops with the downdraft fan built into the cooktop itself, since they are sold for the same islands. We found none in the HVI directory, and the KitchenAid and JennAir pages that sell them, and Miele's downdraft pages, would not load for us, so we have no maker figure to quote and nothing to rank. If you are set on one, ask for the sone rating at high speed and the airflow it was measured at, and treat a single number with no speed the way we treat GE's figure below.
What else you hear from the island
Blowers that speed up on their own. Best's Heat Sentry on the Cattura "adjusts blower speed to high automatically" when it detects excessive heat, and the Sorrento's heat sensor does the same. Thermador's downdraft has an automatic mode. Broan lists Heat Sentry as No on the Elite, which in an open room is a feature.
The rise and the motor. Every unit here lifts its vent with a motor, and none of the makers publishes a figure for that. Zephyr's Treviso and Lift, and the Sorrento, switch the blower on when the vent rises and off when it lowers, so you hear the two together.
Delay and run-on. The Cattura has a 10-minute delay shut-off; Thermador lists delay shut-off; Zephyr's manual tells you to "let the blower run for a few minutes to clean the air after you turn the cooktop off". On an island that is in the middle of the room, the run-on is the part everyone notices.
Lights. The Lift has a dual-level BriteStrip LED; the Cattura has an LED and a filter reminder light; Zephyr's Treviso sheet lists lighting as No, which for a vent that faces the dining table may be a plus.
Makers that stay in their own group
GE lists "CFM/ Sones Rating 500/11.0" for its Universal 30-inch telescopic downdraft, with no speed stated. It is not in the HVI directory, and GE's page says the model is no longer being manufactured. A figure with no speed cannot be placed against the certified ones, so it sits apart.
Faber's Scirocco Plus page lists a "600 cfm blower or remote blower (order separately)", variable speed control and a 14-inch rise, and no sone figure. It is not in the HVI directory. KitchenAid, JennAir and Miele are absent from the directory, and we could not open their pages. FOTILE sells no downdraft in the US; its site returns only articles for the word.
What quiet costs
Quiet on a downdraft is mostly bought with the duct route, and that is a cabinet and floor decision, not a hood decision. Beyond that, the prices run high before you get to quiet: the Thermador is $2,249 plus $949 for its blower, the Bosch $2,049 plus $849, and Zephyr, Best and Broan show no prices at all, so budget for a blower on top of whatever the intake costs. A taller rise captures better from the front burners but gives the vent more to lift; the Lift and Cattura reach 18 inches, the Broan 7. And at 440 to 500 CFM on high, every pick here is around the 400 CFM line where make-up air rules start to apply in homes with fuel-burning appliances. Best's Code Ready Technology caps the Cattura at 400 CFM and Zephyr's ACT caps the Treviso at 390, which also caps the loudest step.
If you are still deciding on the layout, a wall-mounted cooktop with an overhead hood is the quieter kitchen by a wide margin, and a custom hood shell with an insert, which our range hood inserts guide covers, gives you the open look with a certified 5-sone high speed. To decide what figure is worth aiming for elsewhere in the house, see how quiet is quiet enough, room by room.
How we chose
We downloaded the HVI certified products directory (data generated September 23, 2026), took every entry under Downdraft Kitchen Ventilators, and matched each one to a downdraft on its maker's site: the Zephyr Lift, Treviso and Sorrento from Zephyr's product pages and spec sheets, the Best Cattura D49M from Best's product page and PF6 sheet, the Broan Elite from Broan's page and Eclipse spec sheet, and the Thermador and Bosch units from the BSH spec sheets, which carry the HVI performance tables we quote. We left out Viking, which the directory lists with the same figures as the Best PF6, because it is outside the makers this guide covers. Airflow targets come from Best's own sizing guidance. Prices are the makers' own, checked on October 3, 2026; where a maker shows none, we say so.
We did not measure any of these downdrafts ourselves. Every sone and CFM figure is HVI's certified rating or the maker's published one, quoted with the speed and duct direction it describes, and we say each time which is which.
