ROBOVATIONS/CLASSIFICATION RECORD/ROBOT WINDOW CLEANERSRELEASED 2021.11REASSESSED 2026.01.08

HOBOT

HOBOT 388 Ultrasonic

Name: HOBOT 388 Ultrasonic
Brand: HOBOT

Ultrasonic vibration plus systematic path coverage handles routine window cleaning without manual scrubbing within a pane. The constraint is placement: every window is a new setup, and the unit cannot transfer itself between panes.

Behind the classification

Sources we reviewed.

Verified5 sources reviewed

Sufficient public evidence across source types to publish a non-provisional classification.

Sources reviewed

Manufacturer documentation3 itemsReviewed

HOBOT 388 product page specifications, safety documentation, and companion app guide.

Press & video reviews4 itemsReviewed

Technology press coverage of HOBOT 388 at launch and category comparisons from home-tech publications.

Hobot S7 Pro window cleaning robot review – TechRadarTechRadar

Owner reportsOngoing

Consumer forum and retail review aggregates covering pad life, suction reliability, and app connectivity.

Longitudinal signal3 itemsReviewed

Robovations dated log for this robot: 3 tracked entries spanning ~16 months.

How we evaluate evidence →

FIT CHECK

Will the HOBOT 388 Ultrasonic work on your windows?

Describe your windows using the controls. Each choice reads the spec sheet for you, flagging where the HOBOT 388 Ultrasonic is built for your space and where it isn’t.

Window style

Frame style

Building height

Power preference

A classification of fit for the conditions you set — not a recommendation. Verdicts describe engineering design intent, not test results.

SPECIFICATION

The full spec sheet.

Priced below the category median, with every figure charted against the category below.

Dimensional drawing

Key specificationsManufacturer-published

Footprint: 5.83 × 11.61 in · 3.74 in tall
Weight: 2.02 lbs
Wi-Fi: Supported

Where it lands · ranked across 19 robot window cleanersThis robotMedianTypical range

Price$299

$150$850

Near median

Weight2.02lbs

1.3 lbs12.1 lbs

Bottom of range

Position shows where the figure sits across the tracked category — not a quality judgment.

OWNERSHIP

Living with it.

Dependable glass-cleaning performer with no documented regressions; suction seal loss dominates owner reports.

Consistent suction motor performance across multi-year use. Most common failure is suction loss from surface film or residue, not mechanical regression. Firmware updates addressed early app connectivity issues.

Owner effort~40 minhands-on per month

ConsumablesNonereplaceable parts / yr

Reliability trend Stableowner-reported arc

What goes wrong · 4 documented · 1 self-recover

Occasional

Suction loss mid-paneUnit detaches, safety rope arrests fall

Owner fixReseat suction cup, restart path

Occasional

Pad streaking on panesVisible streaks on large windows

Owner fixExchange pad between windows

Occasional

App disconnect via WiFiRemote control lost, unit continues path

Self-recoversReconnect app when in range

Rare

Edge-detection stallUnit pauses at frame edges

Owner fixManual restart via button or app

Upkeep routine

Each useEvery cycle

Remove microfiber pad, rinse with water, and hang to dry before storage. · Wipe suction ring with a clean damp cloth to remove glass cleaner residue that degrades the seal over time.

Monthly12×/yr

Inspect safety rope for fraying; replace if any strand damage is visible before next use.

Seasonal4×/yr

Clean suction motor intake port with a dry brush to remove dust accumulation that reduces grip force. · Check pad contact surface on the cleaning head for mineral buildup; rinse with diluted white vinegar if present.

Yearly1×/yr

Inspect power cable and connector for sheath cracking; manufacturer recommends replacement if outer jacket is compromised.

Cost over time · past the sticker

$299 to buy, with no regularly replaced parts. The purchase price is effectively the full cost of ownership.

Safety notes

CautionSafety rope required for vertical use: Anchor point must support 3 kg minimum load.

CautionCracked or chipped glass prohibited: Damaged surfaces disrupt suction seal and cause falls.

NoteContinuous water drainage risk: Water drains down glass onto sill; manage drip to floors and frames.

RECORD

How the assessment has moved.

Every announcement, release and reassessment behind the current classification.

Coming soon

Just launched

Active updates

Settled

Discontinued

Sep 2023 · UpdateHOBOT 388 app firmware addresses 5 GHz Wi-Fi dropout in owner reports
Mar 2024 · NewsHOBOT 388 street price settles below MSRP as newer models arrive
Jan 2025 · Assessment changeHOBOT 388 three-year assessment holds Level III with maintenance score note
Jul 2026 · AssessmentRobovations Score recorded at 65 of 100
Jul 2026 · AssessmentRobovations Score revised 65 → 73

Editorial comparisons

Common questions

What people actually ask.

5 answered

OperationDoes the HOBOT 388 work on exterior windows?

Manufacturer documentation confirms operation on exterior glass provided the safety rope is anchored and the surface is smooth flat glass. Owner reports describe successful use on exterior-facing glass several stories up, with the safety rope treated as mandatory rather than optional.

OperationHow long does it take to clean one standard window?

Manufacturer specifications cite approximately 10–15 minutes per standard-size pane in systematic path mode. Owner reports note that heavily soiled glass may require a second pass with a fresh pad, extending the session.

OwnershipHow often do the microfiber pads need replacement?

The included pads are washable and reusable. Owner reports suggest useful life of 30–50 wash cycles before cleaning performance visibly degrades. Replacement pads are available from HOBOT and third-party suppliers.

CompatibilityDoes the 388 require a Wi-Fi connection to operate?

No. Basic operation via the onboard button works without a network connection. The companion app adds path-mode selection and remote start but is not required. Manufacturer documentation confirms offline button control.

OperationWhat surfaces can the HOBOT 388 clean?

Manufacturer documentation specifies smooth flat glass only. Owner reports confirm frameless windows, shower enclosure glass, and glass partitions. Textured, frosted, or significantly curved glass is not supported, as suction integrity depends on a flat continuous seal.

Availability

Where it's sold

We may earn commission from qualifying purchases. This does not influence classification.

Amazon See current listings

Cite / Embed

Reference the HOBOT 388 Ultrasonic classification.

Embed the Autonomy Ladder™ mark or copy the citation. The mark links back to this assessment and updates if the classification changes.

RobovationsAutonomy Ladder™Level IIIConditional AutonomyIndependent classification

<a href="https://robovations.com/robots/hobot-388-ultrasonic/" title="HOBOT 388 Ultrasonic — Autonomy Level III (Conditional Autonomy), classified by Robovations on the Autonomy Ladder" rel="noopener" style="display:inline-flex;flex-direction:column;align-items:center;width:208px;max-width:100%;box-sizing:border-box;text-decoration:none;background:linear-gradient(180deg,#ffffff,#fbf8f1);border:1px solid #e7dcc2;border-radius:14px;padding:17px 18px 16px;text-align:center;box-shadow:0 6px 18px rgba(30,58,95,0.09);font-family:'Inter',system-ui,-apple-system,'Segoe UI',Roboto,sans-serif"><span style="display:flex;align-items:center;justify-content:center;gap:7px"><svg width="18" height="18" viewBox="0 0 141 141" aria-hidden="true" style="display:block;flex:0 0 auto"><rect width="141" height="141" rx="20.76" fill="#1e3a5f"/><path d="M98.15,114.54a19.84,19.84,0,0,1-8.53-1.64,15.14,15.14,0,0,1-5.93-5.14,41.35,41.35,0,0,1-4.54-8.83l-5-14.15a54.15,54.15,0,0,0-2.54-5.51,8.7,8.7,0,0,0-3.08-3.39,9.89,9.89,0,0,0-5.14-1.15H61a10.13,10.13,0,0,0-2.18.25V98.21a9,9,0,0,0,.79,4.29c.52.93,1.75,1.55,3.69,1.88l6.77.84v7.62H32.21v-7.62l5.93-1a4.05,4.05,0,0,0,3-1.57c.48-.8.72-2.34.72-4.6V42.43a8.48,8.48,0,0,0-.72-4.17c-.49-.77-1.58-1.31-3.27-1.64l-5.69-.84V28.16H66.45a68.36,68.36,0,0,1,13.79,1.27A33.28,33.28,0,0,1,90.77,33.3,18.6,18.6,0,0,1,97.48,40a19,19,0,0,1,2.36,9.74,16.66,16.66,0,0,1-1.45,7,20.72,20.72,0,0,1-3.87,5.74,27.34,27.34,0,0,1-5.44,4.42A37.64,37.64,0,0,1,83,69.89a29.7,29.7,0,0,1-6,1.7v.48a22.17,22.17,0,0,1,9.31,3.63,17.45,17.45,0,0,1,5.45,7.75l3.51,8.71q1.56,4,2.9,6.65a11.51,11.51,0,0,0,3,4,7.23,7.23,0,0,0,4.6,1.33,15.65,15.65,0,0,0,2.3-.18,23.61,23.61,0,0,0,2.9-.66l1.58,6.17a21.54,21.54,0,0,1-6.23,3.69A22.57,22.57,0,0,1,98.15,114.54ZM64.52,67.11a21.12,21.12,0,0,0,9.37-1.87,13,13,0,0,0,5.81-5.51,17.82,17.82,0,0,0,2-8.71,14.86,14.86,0,0,0-2-8.17A11.65,11.65,0,0,0,74,38.32a25.89,25.89,0,0,0-9.31-1.45H59v30q1.81.12,3.15.18C63,67.09,63.79,67.11,64.52,67.11Z" fill="#ffffff"/></svg><span style="font-size:12.5px;font-weight:600;letter-spacing:0.04em;color:#1e3a5f">Robovations</span></span><span style="align-self:stretch;height:1px;background:linear-gradient(90deg,transparent,#e0c485,transparent);margin:11px 0 13px"></span><span style="font-size:10px;font-weight:700;letter-spacing:0.15em;text-transform:uppercase;color:#7d6022">Autonomy Ladder&#8482;</span><span style="display:flex;justify-content:center;margin:13px 0 13px"><span style="display:inline-flex;align-items:flex-end;gap:6px;height:42px"><span style="display:block;width:9px;height:16px;border-radius:2px;background:#4678a0"></span><span style="display:block;width:9px;height:22px;border-radius:2px;background:#4678a0"></span><span style="display:block;width:9px;height:29px;border-radius:2px;background:#4678a0"></span><span style="display:block;width:9px;height:35px;border-radius:2px;background:rgba(20,32,46,0.12)"></span><span style="display:block;width:9px;height:42px;border-radius:2px;background:rgba(20,32,46,0.12)"></span></span></span><span style="display:inline-flex;align-items:center;padding:4px 11px;border-radius:4px;font-weight:700;font-size:13px;letter-spacing:0.08em;color:#fff;line-height:1.2;white-space:nowrap;background:#4678a0;">Level III</span><span style="font-size:14px;font-weight:600;color:#111827;margin-top:9px">Conditional Autonomy</span><span style="font-size:10.5px;color:#6b7280;margin-top:7px;letter-spacing:0.02em">Independent classification</span></a>

Citation

Robovations. "HOBOT 388 Ultrasonic: Autonomy Level 3 (Conditional Autonomy)." Autonomy Ladder™, assessed June 2026. https://robovations.com/robots/hobot-388-ultrasonic/

Where to next

Three ways to keep going.

For evaluators

Compare with a peer.

See the HOBOT 388 Ultrasonic and HUTT A1 side by side: autonomy level, Robovations Score, readiness, and price. Classification, not a verdict.

See the full comparison

Or compare with Ecovacs Winbot W3 Omni, HOBOT S7 Pro, HOBOT 2S.

For browsers

See every Level III.

Every robot we’ve classified at conditional autonomy. Sorted by readiness, score, and price. Filter by category, manufacturer, or release date.

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Updated weekly with new entries and reclassifications.

HOBOT 388 Ultrasonic

Will the HOBOT 388 Ultrasonic work on your windows?

The full spec sheet.

Living with it.

How the assessment has moved.

How HOBOT 388 Ultrasonic compares.

What happens when a robot window cleaner loses suction or power?

Robotic window cleaners: which design fits which window?

Window robots: which handle more than maintenance dust?

What people actually ask.