HOBOT
Comparison · 2 robots
Hobot 298 · HOBOT 388 Ultrasonic
All robot window cleaners. Every measure below is plotted against the full class, so a difference can be read against how much the class itself varies.
- Hobot 298
- HOBOT 388 Ultrasonic
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
Hobot 298HOBOT 388 Ultrasonic
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
5875
- Hobot 29858
- HOBOT 388 Ultrasonic75
18median 72 across 433 scored robots100
Coverage and navigation10% of score
Does it work the whole area, and hold that between runs
5270
- Hobot 29852
- HOBOT 388 Ultrasonic70
0median 70 across 421 scored robots100
Edge-case recovery10% of score
Does it recover from the failures its category presents
5650
- Hobot 29856
- HOBOT 388 Ultrasonic50
18median 52 across 320 scored robots100
Operating envelope4% of score
How far conditions can vary before performance drops
5765
- Hobot 29857
- HOBOT 388 Ultrasonic65
28median 68 across 397 scored robots100
Dependability
Field failure rate16% of score
Documented hardware failures per owner-year
8585
- Hobot 29885
- HOBOT 388 Ultrasonic85
6median 70 across 359 scored robots100
Software stability14% of score
Whether updates fix more than they break
7133
- Hobot 29871
- HOBOT 388 Ultrasonic33
15median 65 across 342 scored robots100
Support longevity10% of score
Committed parts, service and updates, with dates
8273
- Hobot 29882
- HOBOT 388 Ultrasonic73
0median 62 across 429 scored robots100
Ownership burden
Routine maintenance12% of score
Hands-on time it asks for in normal operation
3234
- Hobot 29832
- HOBOT 388 Ultrasonic34
22median 67 across 434 scored robots100
Consumables8% of score
Parts that must be bought to keep it working
6691
- Hobot 29866
- HOBOT 388 Ultrasonic91
8median 69 across 434 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.
Price21 with a published figure
$249$299
- Hobot 298$249
- HOBOT 388 Ultrasonic$299
$150median $349$850
Weight22 with a published figure
2.6 lbs2 lbs
- Hobot 2982.6 lbs
- HOBOT 388 Ultrasonic2 lbs
1.3 lbsmedian 3.1 lbs4.8 lbs
Height23 with a published figure
3.5 in3.7 in
- Hobot 2983.5 in
- HOBOT 388 Ultrasonic3.7 in
2.2 inmedian 3.3 in9.4 in
Not compared, because fewer than two of these robots carry a published figure: Suction, Runtime, Charge time, Noise.
04 Ownership
What the numbers leave out.
The trade-off
What each design gives up to be good at what it is good at.
Hobot 298
Mains power removes recharge cycles, and an embedded UPS holds the robot in place for 20 minutes through an outage, but the 4 meter cord ties the machine to a socket within a few paces of the pane.
HOBOT 388 Ultrasonic
Applying water as a mist rather than a soak keeps run-off off the sill, but a saturated pad on consecutive heavily-soiled panes still requires a mid-session swap that interrupts the automated workflow.
Coverage within a single pane is systematic and unattended; the unit cannot advance to the next pane without the owner relocating it and re-anchoring the rope.
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.
Hobot 298
- High-rise or multi-story installations requiring extended reach
- The power cord is 4 meters and the supplied safety rope is 4.5 meters, so both the socket and the rope's indoor anchor point have to sit close to the pane being worked. Windows further from an interior socket than that are outside what this model reaches.
- Homes without adjacent power outlets or outdoor outlets within cable run
- Extension cord use is discouraged by manufacturer for safety. Interior outlet management becomes critical; wet-environment electrical safety is owner's responsibility.
- Specialty or curved glass surfaces
- Square pad geometry and fixed nozzle positioning leave corners uncleaned. Tempered or heavily tinted windows challenge optical edge detection; manual repositioning is frequent.
HOBOT 388 Ultrasonic
- Users expecting hands-free multi-window automation
- Every pane requires manual placement, pad attachment, and safety rope anchoring. The unit automates the scrubbing path within a pane but does not eliminate per-window setup effort.
- Homes with textured, frosted, or divided-pane glass
- Surface irregularities break the suction seal. Owner reports confirm the unit detaches or loses path on patterned or divided glass, which is a safety risk in addition to a cleaning failure.
- Buyers seeking a fully autonomous set-and-forget appliance
- Window cleaners in this category require active supervision per session. The 388 automates path coverage within a pane, not the overall cleaning workflow across a home.
- Owners with small standard windows cleaned rarely
- Manual squeegee effort on small panes is often faster than the 388 setup cycle. The time-savings case is strongest on large or difficult-to-reach glass.
What stays your job
The upkeep ownership hands back to you, whatever the autonomy level says.
Hobot 298
- Weekly: Rinse pad and inspect nozzle for mineral deposits; test suction by listening for motor speed consistency.
- Monthly: Clean intake ports and motor filter with soft brush; soak nozzle in distilled vinegar if spray pattern weakens.
- Every 3-4 months: Replace cleaning pads (~$20-25 per pair); inspect power cable for insulation damage.
- Annually: Replace motor intake filter (~$15); deep-clean nozzle assembly by soaking in 50/50 vinegar-water solution.
- As needed: Replace vacuum motor assembly if suction falls below specification (~$80, typical at 5-6 year mark with regular use).
HOBOT 388 Ultrasonic
- After every use: Remove microfiber pad, rinse with water, and hang to dry before storage.
- After every use: Wipe suction ring with a clean damp cloth to remove glass cleaner residue that degrades the seal over time.
- Monthly: Inspect safety rope for fraying; replace if any strand damage is visible before next use.
- Every 3-6 months: Clean suction motor intake port with a dry brush to remove dust accumulation that reduces grip force.
- Every 3-6 months: Check pad contact surface on the cleaning head for mineral buildup; rinse with diluted white vinegar if present.
- Annually: Inspect power cable and connector for sheath cracking; manufacturer recommends replacement if outer jacket is compromised.
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 |
|---|---|---|---|
| Hobot 298 | Provisional | 4 | Aug 2026 |
| HOBOT 388 Ultrasonic | Provisional | 7 | Aug 2026 |
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