Gardena
Comparison · 2 robots
Gardena Sileno Life 750 · Robomow RK4000
All robot lawn mowers. Every measure below is plotted against the full class, so a difference can be read against how much the class itself varies.
- Gardena Sileno Life 750
- Robomow RK4000
01 Classification
What each one does on its own.
The Autonomy Ladder is the same five rungs for every robot on the site. A rung describes the conditions a robot handles without you, not how good it is.
V
Generalized
Any task, any setting
IV
Environmental
Handles new obstacles without help
III
Conditional
Finishes familiar jobs on its own
II
Assisted
Runs preset routines, needs rescue
Gardena Sileno Life 750Robomow RK4000
I
Manual
One action, on command
02 Assessment
Where they actually differ.
The Robovations Score is nine inputs across three pillars, each weighted as shown and each scored so that more is better. A robot can lead on one and trail on another, which is the point of showing them apart. Cost of ownership and data handling are reported on each robot's own page and are never averaged into the score.
Capability
Task completion16% of score
Does it finish the job it is sold to do, unattended
7578
- Gardena Sileno Life 75075
- Robomow RK400078
18median 72 across 381 scored robots100
Coverage and navigation10% of score
Does it work the whole area, and hold that between runs
5055
- Gardena Sileno Life 75050
- Robomow RK400055
15median 70 across 371 scored robots100
Edge-case recovery10% of score
Does it recover from the failures its category presents
3869
- Gardena Sileno Life 75038
- Robomow RK400069
18median 50 across 287 scored robots100
Operating envelope4% of score
How far conditions can vary before performance drops
6270
- Gardena Sileno Life 75062
- Robomow RK400070
25median 68 across 345 scored robots100
Dependability
Field failure rate16% of score
Documented hardware failures per owner-year
8181
- Gardena Sileno Life 75081
- Robomow RK400081
6median 70 across 371 scored robots100
Software stability14% of score
Whether updates fix more than they break
5574
- Gardena Sileno Life 75055
- Robomow RK400074
15median 65 across 300 scored robots100
Support longevity10% of score
Committed parts, service and updates, with dates
10073
- Gardena Sileno Life 750100
- Robomow RK400073
0median 63 across 377 scored robots100
Ownership burden
Routine maintenance12% of score
Hands-on time it asks for in normal operation
5640
- Gardena Sileno Life 75056
- Robomow RK400040
22median 65 across 382 scored robots100
Consumables8% of score
Parts that must be bought to keep it working
8966
- Gardena Sileno Life 75089
- Robomow RK400066
8median 69 across 381 scored robots100
03 Measured against the class
How far apart is a long way?
A number only means something next to the spread it sits in. Each track below is the real range across every classified robot in the class, with the median marked.
Price75 with a published figure
$1,199$1,999
- Gardena Sileno Life 750$1,199
- Robomow RK4000$1,999
$549median $1,999$5,999
Runtime88 with a published figure
65 min120 min
- Gardena Sileno Life 75065 min
- Robomow RK4000120 min
30 minmedian 110 min240 min
Charge time88 with a published figure
60 min110 min
- Gardena Sileno Life 75060 min
- Robomow RK4000110 min
30 minmedian 90 min300 min
Noise88 with a published figure
57 dB65 dB
- Gardena Sileno Life 75057 dB
- Robomow RK400065 dB
50 dBmedian 60 dB82 dB
Weight96 with a published figure
16.1 lbs27.3 lbs
- Gardena Sileno Life 75016.1 lbs
- Robomow RK400027.3 lbs
13 lbsmedian 29.8 lbs134 lbs
Height97 with a published figure
9.1 in8.7 in
- Gardena Sileno Life 7509.1 in
- Robomow RK40008.7 in
7.5 inmedian 11 in16.5 in
Not compared, because fewer than two of these robots carry a published figure: Suction.
04 Ownership
What the numbers leave out.
The trade-off
What each design gives up to be good at what it is good at.
Gardena Sileno Life 750
Random-pattern cutting inside a fixed wire keeps the machine simple and the setup permanent. You get an even lawn from cutting often; you do not get route planning or obstacle avoidance.
Robomow RK4000
Boundary-wire guidance eliminates line-of-sight operator control, but requires significant one-time and seasonal infrastructure maintenance that systematic-mapping systems avoid.
Random coverage patterns reduce planning complexity, but result in less uniform grass height and longer mowing cycles than systematic mapping approaches.
Who each one is wrong for
Stated by the record itself. A robot being wrong for a household is a fact about fit, not a fault.
Gardena Sileno Life 750
- Lawns with complex topography, slopes, or frequent obstacles
- No avoidance capability; slopes >15°, rocks, toys, or garden furniture will cause collisions or stalling requiring manual recovery.
- Users wanting wire-free, zero-setup autonomous operation
- Boundary-wire infrastructure is mandatory. RTK or vision-based alternatives not available on this model.
- Large estates or multi-zone properties over 750 sq m
- Rated for 750 sq m maximum; properties larger than this exceed rated coverage and would require multiple units.
Robomow RK4000
- Complex yards requiring precise perimeter definition
- Properties with irregular boundaries, multiple islands, or intricate garden beds require frequent wire adjustments and manual intervention unsuitable for autonomous operation.
- Operators unwilling to manage seasonal wire maintenance
- Wire inspection, replacement, and winterization add overhead unsuitable for users preferring fully hands-off operation beyond blade swaps.
- Small lots well inside the rated area
- The RK4000 is rated for lawns up to 4,000 sq m, sold in the US as up to one acre. On a few hundred square meters the mower, its base station and its wire run are more hardware and more installation than the ground calls for.
- Terrain steeper than the rated slope
- Robomow's published maximum mowing slope for the RK4000 is 45 percent, which is 24 degrees. Banks steeper than that are outside the rating.
- Owners prioritizing stripe patterns or aesthetic consistency
- Perimeter-first with randomized fill does not produce striped patterns or uniform cutting height; systematic mapping mowers better suit aesthetic lawn maintenance.
What stays your job
The upkeep ownership hands back to you, whatever the autonomy level says.
Gardena Sileno Life 750
- Weekly: Dock cleaning and mower base inspection for grass clippings and debris buildup.
- Monthly: Blade inspection for dulling; jagged grass edges indicate wear requiring replacement.
- Every 3-6 months: Replace the blades as a set (typically €15-25). They are flip-and-replace razors rather than sharpenable blades; grinding an edge back removes the coating and leaves a weakened blade spinning on an unattended machine.
- Annually: Boundary wire inspection for breaks and corrosion; re-splicing or perimeter repair as needed (€0-500+ depending on property size and condition).
- Seasonally: Spring startup (full charge, app pairing verification, dock contact cleaning); autumn storage with the mower cleaned, the battery charged rather than left flat, and the dock brought indoors if freezing is expected.
Robomow RK4000
- After every use: Clear the cutting deck of compacted grass; inspect for wrapped grass or debris.
- Weekly: Check base station charging contacts for debris or corrosion; verify the station remains level and obstruction-free.
- Monthly: Inspect boundary wire for visible damage, gaps, or loose pegs.
- By inspection: Check blade condition and replace when edges are rounded, chipped, or bent. Robomow publishes no fixed interval or price for RK4000 blades.
- Annually: Perform a full boundary-wire inspection and continuity check.
- Seasonally: Recheck base station position, clear accumulated leaves from the charging area, and confirm cutting height as the lawn enters dormancy.
05 Evidence
How much each of these is standing on.
Classifications rest on different depths of evidence. A pre-release assessment and a verified one are not the same kind of claim.
| Robot | Evidence status | Sources reviewed | Last assessed |
|---|---|---|---|
| Gardena Sileno Life 750 | Verified | 5 | Aug 2026 |
| Robomow RK4000 | Provisional | 4 | Sep 2026 |
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