A hedge trimmer puts its motor and blade at chest height, closer to your ears than any other outdoor tool. That makes the operator ear figure the one that matters, and in this category it is unusually well documented: STIHL declares every battery trimmer it sells under EN 62841-4-2, with an uncertainty value and a guaranteed sound power ceiling under EU directive 2000/14/EC.
Twelve battery models sold in the US carry maker declarations. At the ear they run from 76 dB(A) for a full size trimmer to 86.47; guaranteed sound power runs from 86 to 96 dB(A). A STIHL shrub shear goes lower still.
Smaller is not quieter
The most useful finding comes from STIHL's own range. The compact homeowner HSA 30 and HSA 40 declare 82 dB(A) at the ear. The full size HSA 60 declares 77, and the professional HSA 100 declares 76. A buyer choosing the small model for a quiet life would pick the louder tool by five or six decibels at the ear.
The same holds for sound power: the HSA 60's guaranteed 87 dB(A) is five below the small models' 92. Blade length does not predict noise. Declared figures do.
Two numbers, never one ranking
Every declared trimmer here carries two quantities. LpA is pressure at the operator's ear. LWA is sound power, the tool's total output, with a guaranteed ceiling the maker must not exceed. We rank on the ear figure, show the guaranteed power beside it, and never mix them, as in our string trimmer guide. The sound power vs sound pressure explainer covers why.
Who declares, and how
STIHL declares fully in its manuals. Its US manual server refused our requests, so every STIHL figure here comes from its international English editions on STIHL's own document server, with the document number cited. Husqvarna prints both quantities on its US product pages with no standard or K value. EGO publishes nothing in the US and declares in its European manuals, so we map EU models to US ones by blade, capacity and weight, and flag each match.
The EGO results are worth knowing if you are already on its batteries: its 24 inch HT2410 maps to 86.47 dB(A) at the ear, the loudest battery trimmer in this survey, and its quietest US model maps to 83.45.
What gas costs
STIHL's own gas HS 45 declares 97 dB(A) at the ear under ISO 22868 and a guaranteed 105 dB(A). Against the HSA 100's 76 and 86, that is about 20 dB(A) at the ear from one maker's paperwork. A gap that size is the difference between hearing protection as a habit and hearing protection as a requirement.
The silent aisle
Black+Decker, Worx, Greenworks, Makita US, DeWalt, Milwaukee and Ryobi publish no noise figure for any US hedge trimmer we checked. Husqvarna's consumer 320iHD60 page omits its figures too. None of them can be ranked, however quiet they might be.
We did not measure any of these trimmers. Every figure is the maker's own, quoted as published, with the standard, K value and document identified wherever the maker identified them.
