Which box fan brands publish a decibel rating?
Only three of the dozen box fan brands we checked, Air King, Vornado and Pelonis, publish a decibel figure; Lasko, which sells the most models, says sound testing "is not a requirement" for its residential fans.
Most box fan makers simply don't publish a decibel figure. Lasko, which sells more box fan models than any brand we checked, explains why on its help site: sound testing "is not a requirement" for its residential fans, and it hopes "to have information surrounding sound testing in the future."
One of its spec tables even shows 0 dBa for both high and low speed, which is an unfilled template, not a silent fan.
Holmes, Genesis, Comfort Zone, BLACK+DECKER and Amazon Basics publish no figure on any manufacturer page we could read. That leaves three:
- Air King publishes dBA for each of its three speeds, next to airflow and wattage.
- Vornado publishes dBA for its box fans, but does not say which speed or how it was measured.
- Pelonis publishes only a maximum.
Retailer listings often show a "noise level" row. Treat those with suspicion: they are entered by sellers, they give no speed or distance, and we found two that contradict the manufacturer outright.
Pelonis's own site says 73 dB for a fan whose Amazon listing says 34. Two different brands' listings carry the identical figure of 63.3 dB.
How many decibels is a box fan on high and low?
Air King's box fan lists 60 dBA on high, 55 on medium and 51 on low, but no box fan maker we checked states the distance behind its figures.
A decibel figure means little without two things: the speed it was measured at and the distance. No box fan maker we checked states the distance. That is why we would not use these numbers to compare one brand against another, only to compare models within a brand.
Two rules of thumb help, both from fan-industry engineering guidance. Every increase of 10 dB sounds roughly twice as loud, so a fan at 60 dBA is about twice as loud as one at 50. And in open space, each doubling of distance cuts the level by about 6 dB, so a fan across the room is markedly quieter than one at the bedside.
The Air King's figures show what speed does: 60 dBA on high, 55 on medium, 51 on low. Dropping from high to low makes it sound roughly half as loud, while still moving about two-thirds of the air.
To see how 60 dBA on high and 51 on low sit beside everyday sounds such as a fridge hum or normal conversation, see our decibel chart.
Is a box fan with more speeds quieter?
Yes, a box fan with more speeds can be quieter, because the quietest box fan is mostly the one running at the slowest setting that still moves enough air.
That is the argument for a fan with more than three speeds. A typical box fan's "low" is fixed by the factory; if it is louder than you want, there is nothing below it.
Vornado's Model 80X runs its DC motor at any of 99 speeds, using as little as 1 W, and its published range runs from 28 dBA to 61. You can set it just above still air for sleeping and turn it up in the afternoon. You pay for that: it costs roughly three times as much as a basic box fan.
That 28 is the lowest figure Vornado prints for any of its fans, and our Vornado fan decibels page lists all 99 current models that carry one.
How loud are box fans in independent tests?
In Consumer Reports' tests, as Quartz reported them, three 20-inch box fans averaged 63 dB (Amazon Basics), 67 dB (Genesis G20) and 78 dB (an AirFort model).
With so few published figures, lab testing fills the gap. Consumer Reports tests room fans for noise, and Quartz reported its results for three 20-inch box fans: the Amazon Basics averaged 63 dB, the Genesis G20 averaged 67 dB, and an AirFort model averaged 78 dB.
The same report notes that pedestal fans run quieter than box fans. If a stand fan suits your room, our pedestal fan guide sorts the figures Lasko, Vornado and others publish for them.
Those averages are not comparable with the manufacturer figures above, because the methods differ. What they do show is a wide spread between box fans that look almost identical on a shelf.
How do you make a box fan quieter?
To make a box fan quieter, set it on a level surface, clean the blades and check that the blade and grille screws are tight, the fixes makers' own support pages suggest for a rattle or buzz.
A rattle or a buzz is often fixable. The makers' own support pages suggest where to start:
Put it on a level surface.
Amazon Basics' manual gives this as the fix for vibration, and Air King asks for a stable, flat, level surface.
Clean the blades.
Lasko's cleaning guide says to remove the front grille screws, wipe the blade with a damp cloth and vacuum the back of the motor, keeping water away from it. In its tower fan guidance, Lasko names debris on the blade as a cause of vibration.
Check that everything is tight.
Lasko notes the blade is held friction-tight on its shaft and describes re-seating it and retightening the grille screws. It also says the feet must be pushed fully on until flush.
Buy one you can open.
Both Vornado box fans and the Pelonis advertise a removable grille for cleaning. Holmes tells owners not to remove the blade.
Can a box fan go in a window or take a filter?
No, not most box fans: Vornado, Genesis, Amazon Basics and Air King all forbid window or wet use in their manuals, and Vornado tells owners not to add a filter.
Do not assume a box fan can go in a window. Lasko is the exception, with weather-resistant motors on several models, though it says to take the fan out during heavy weather.
Check the manual for your exact model: one Lasko product page says the fan is fine in a window in minor rain, while the manual linked from that page says not to use it in or near a window.
Strapping a furnace filter to a box fan is a do-it-yourself air cleaner that the EPA has researched for wildfire smoke. Vornado tells owners not to do it with its box fans, saying the motor can overheat.
The EPA reports that UL testing of box fans with filters found no observable fire hazards, and recommends using a fan made since 2012 that carries a UL or ETL mark. For this guide's purposes, note what else the EPA says: adding a filter makes the fan louder.
White noise
Some people buy a box fan for the sound. Lasko and Comfort Zone both market their fans that way. If that is you, you may not want the quietest model here at all. If you want the opposite, a fan that stays out of the way all night, see the part of our tower fan guide on sleep modes.
Where do box fan shoppers go wrong?
Box fan shoppers go wrong in five ways, starting with trusting the seller-entered "noise level" row on a retailer listing.
Trusting the "noise level" row on a retailer listing
It is seller-entered, and we found it contradicting the manufacturer.
Reading 0 dB as silent
It is an empty field.
Comparing decibels across brands
Without a stated distance and speed, the numbers are not comparable.
Putting any box fan in a window
Most manuals forbid it.
Blaming the motor for a rattle
Try a level surface and a screwdriver first.
Vornado's 40 dBA for the Model 80 names no speed and Air King's 51 dBA on low names no distance, so neither can be set against the other, a box fan version of the problem with comparing decibel ratings across brands.
The Air King's low speed may be fine in the garage or workshop it suits, but how quiet is quiet enough for a bedroom may send you to the 80X and its 28 dBA end instead.
If a box fan you own has grown louder over time, Lasko's support pages point to dust build-up and a blade out of balance, so start there before the other reasons an appliance gets louder.
