A robot mower’s dB number needs a label before you can compare it. Sound power describes the source’s acoustic output; sound pressure describes the level at a measurement position. Both may use dB(A), so the unit alone does not tell you which quantity you are reading.
Reviewed September 28, 2026. This guide interprets published specifications and provides an observation checklist. SmartYardLab has not measured these mowers’ noise.
One mower can have several valid noise figures
The 2026 Automower 305/310 Mark II/315 Mark II manual, technical data on page 50, illustrates why a single unlabeled number is inadequate. For the 310 Mark II it reports:
| Reported quantity | Value | How to read it |
|---|---|---|
| Measured sound power | 58 dB(A) | Compare with the same quantity and test method on another mower. |
| Sound-power uncertainty | 1 dB(A) | Keep this with the measured value. |
| Sound pressure at the operator’s ear | 50 dB(A) | A specified test position, not your neighbor’s window. |
The manual gives sound-pressure uncertainty separately as 2–4 dB(A). These values are manufacturer measurements, not contradictory claims about one machine being “58 dB loud” and “50 dB loud.”
The UK Health and Safety Executive’s guidance on noise reporting distinguishes emission sound pressure from sound power, and explains the need to report uncertainty, test methods and operating conditions. Use those fields to make a comparison; do not subtract a phone reading at your patio from a sound-power specification.
Check these fields before choosing the quieter model
| Field | Mower A | Mower B |
|---|---|---|
| Exact model and manual revision | Fill in | Fill in |
| Quantity: power, pressure or another labeled figure | Fill in | Fill in |
| Measured or guaranteed value, where specified | Fill in | Fill in |
| Test standard and operating condition | Fill in | Fill in |
| Uncertainty | Fill in | Fill in |
| Measurement position, for pressure | Fill in | Fill in |
Comparison example: “60 dB(A) sound power” for Mower A and “55 dB(A) at a stated distance” for Mower B do not establish that B is 5 dB quieter. The quantities differ. Ask for matching measurements before ranking them.
Also consider the hours needed to cover your lawn. A specification does not describe whether the mower will pass a nearby bedroom several times each evening. Put noise alongside coverage and available operating hours in your buying comparison.
Evaluate the places where the sound matters
For a demonstration or an existing installation, write down three listening positions: the patio, a relevant window and the property edge. Observe from safe locations outside the active work area and maintain the manual’s separation distance.
- Keep the observation comparable. Use the same position and note whether the mower is cutting, turning or returning to charge.
- Record context. Note distance, open or closed windows, traffic, wind and nearby walls. A quiet afternoon and a busy street are different listening conditions.
- Describe the character. A steady cutting sound, intermittent rattle and alarm are different concerns even when a display shows similar numbers.
- Record the duration. Note how long the mower remains near that position and how often it returns during its normal schedule.
This is a practical comfort check, not a standardized noise test or proof of compliance. Before setting early or late mowing hours, check the rules that apply to your property. A low product rating does not itself authorize a schedule.
A new rattle or vibration needs a maintenance check
Stop the mower and follow its isolation procedure before inspecting it; wait until moving parts have stopped. Do not reach under a running machine to identify the sound.
Husqvarna’s buzzing and vibration guidance identifies cutting-system imbalance, including accidentally fitting two blades to one screw, damaged or mismatched blades, and heavy grass load. For the blade system described there, it calls for replacing all three blades together with new screws. Follow your own model’s blade arrangement; the number is not universal.
If the sound began immediately after blade replacement, compare the fitted parts and arrangement with the manual before assuming the motor has failed. Our blade replacement guide explains the checks. If there is visible damage, persistent vibration or metallic grinding, leave the mower off and obtain service advice.
A useful support report includes a recording from a safe distance, the model, the last maintenance action, whether the sound occurs while driving or cutting, and the exact error message. A recording can document a change; it cannot diagnose an internal bearing or electrical connection by itself.
Update — September 28, 2026: Separated sound-power and sound-pressure figures and added a comparable-specification checklist.