How many decibels is a shop vac?
Sorted by number, Makita wins at 60 dB(A) and Milwaukee loses at 87. Read the labels and that order collapses.
| Maker | Figure | What it describes |
|---|
| Milwaukee | "Sound Power Level: 87 dB(A)" | Sound power, everything the vac radiates in total |
| Metabo HPT | 62 dB | No-load, Standard Mode, nothing being vacuumed |
| Festool | 71 dB(A) | Sound pressure per EN 60335-2-69, uncertainty 3 dB |
| Bosch | 70 dB | Power Broker dial at maximum |
| Makita, Fein, Karcher | 60 to 76 dB(A) | Sound pressure, the level a microphone reads at one position, no condition stated |
For any one vac, sound power always reads much higher than its sound pressure. Milwaukee's 87 and Metabo HPT's no-load 62 therefore line up with nobody else's figures, and shop vac ratings taken on different bases cannot be ranked together.
That leaves an awkward choice at the top. Makita's 60 dB(A) is the lowest number in the category and comes with no condition at all, while Festool's 71 dB(A) is higher and far better documented. Makita ranks first because this page quotes what makers publish. Festool's is the figure we would trust.
Makita, Festool, Fein and Bosch publish 60 to 71 dB(A) for their dust extractors, against 73 or 74 dB(A) for each of Karcher's four shop vacs.
The two are different machines. A dust extractor connects to a power tool, starts with it, runs HEPA or dust-class filtration and uses a hose around 35 mm across. A shop vac from Karcher or the big-box brands has a larger hose, a bigger drum and a simpler filter. Our guide to dust extractors ranks thirteen of them on their own declarations.
The gap is real. So is the price gap, though only Karcher publishes what its machines cost.
Why is my shop vac so loud?
Usually because it is starved of air. When the float rises and airflow stops, Ridgid's manual explains, the motor noise becomes higher in pitch because the motor speeds up. A clogged filter or a blocked nozzle does the same.
That one line is the most useful in any of these manuals, because it turns into a checklist.
Use a bag. A paper, fleece or slurry bag extends both high performance and the time before the filter clogs, in Bosch's account.
Run the filter cleaning when suction drops noticeably; regular use maintains maximum performance longer.
Keep the filter dry. A moist main filter clogs faster on dry material, so dry it or swap it, Festool advises, and Ridgid adds that a wet filter used on dry material clogs quickly and is hard to clean.
Watch for lost suction, which Ridgid lists among the signs of abnormal operation.
One warning stands out: Bosch says the filter cleaning cycle is loud enough that people nearby should be told before it runs.
Filtration decides fine dust work
For fine dust the filter counts for more than the decibels. For ordinary workshop debris, any of these shop vacs will do.
Makita's VC4210L filters 99.97% of particles at 0.3 microns. Bosch's manual is direct about silica: always use the HEPA filter and fleece bag, and leave the automatic filter cleaning on. Festool's CT 26 EI is HEPA. Fein's Turbo II is dust class L, with no HEPA filter in that version.
Only Karcher lists prices
Karcher's site prices all four: $99.99 for the WD 3, $199.99 for the WD 4, $249.99 for the WD 5 P and $349.99 for the WD 6 P S, all in stock when we checked. Festool, Fein, Makita, Bosch, Milwaukee and Metabo HPT publish none.
Five mistakes that make a quiet vac loud
The first is comparing a sound power figure with a sound pressure one. Milwaukee's 87 is not the same kind of number as Makita's 60.
Trusting a bare figure over a documented one is the second, and Festool's 71 dB(A) tells you more than Makita's 60. Third, running a clogged filter makes the vac louder and higher pitched, and it cleans worse. Fourth, a wet filter on dry dust is a mistake Festool and Ridgid both warn against.
Last, skipping hearing protection because the number looks low. Every manual requires it anyway.
