The six scores

Every box gets the same six category scores out of 10, and an overall that weights them. The weighting is deliberate: odor and cleaning are why people buy these things, and a beautiful app does not rescue a box that leaks smell.

Cleaning 22%

How completely and reliably it clears waste on every cycle.

Odor control 22%

Seal quality, filtration, and how the room smells after a week.

Safety 20%

Sensor coverage, pinch protection, and behaviour when a cat re-enters.

App 12%

Setup, connection reliability, and whether the data is actually useful.

Maintenance 12%

How long a full clean takes and how well the unit comes apart.

Value 12%

Purchase price plus consumables against what it delivers.

The seven measurements

These are the tests. They are deliberately dull and deliberately repeatable — the point is that a score from one box means the same as a score from another.

  1. Cycle completeness

    How much waste the box actually clears, cycle after cycle.

    Twenty measured deposits of standardised synthetic waste across a 30-day run, weighed before and after. We record the percentage cleared, the number of cycles that leave residue, and every jam.

    Feeds: Cleaning

  2. Odor at day seven

    Whether the room still smells acceptable a week in.

    A sealed 12 m³ test room, ammonia and hydrogen sulphide measured at 1 m and 3 m on days 1, 3, 5 and 7, with the drawer left unemptied throughout. Filters are fitted new at the start of each run.

    Feeds: Odor control

  3. Sound at three feet

    How loud a cycle is where you would actually hear it.

    A-weighted peak and average measured at 3 ft and 10 ft in a room with a 32 dB noise floor, across ten cycles. We publish the average; the peak matters for bedrooms and we note it in the review.

    Feeds: Cleaning, Maintenance

  4. Safety sensor response

    What happens when a cat enters mid-cycle.

    A weighted, cat-sized test object is introduced at five points in the rotation. We record whether the unit stops, reverses or continues, and the time to stop. We test at 3 lb, 8 lb and 18 lb. No live cat is ever used for this.

    Feeds: Safety

  5. Setup and teardown

    How long it takes to get running, and to fully clean.

    Timed from sealed box to first successful cycle, then a timed full disassembly, wash and reassembly. We count tools required and parts that cannot be removed.

    Feeds: Maintenance

  6. App reliability

    Whether the connection and the data hold up.

    Thirty days of continuous monitoring: dropouts logged, notification latency measured, and reported weights checked against a calibrated scale.

    Feeds: App

  7. True cost per year

    What it costs once you own it.

    Bags, filters, trays and cartridges at manufacturer-recommended replacement intervals, priced at the cheapest genuine source. Published as a five-year total on every review.

    Feeds: Value

What we will not do

  • We do not test safety systems on live cats. Ever. Weighted test objects only.
  • We do not accept a free unit in exchange for a review, a score, or a placement.
  • We do not let a brand see a score before it publishes.
  • We do not change a ranking because a retailer's commission rate changed.
  • We do not publish a measured score without stating the date it was measured.

How we make money

Affiliate links. When you buy through a Check Price button we may earn a commission from the retailer at no extra cost to you. Rankings are generated from the scored database — the code that orders a ranking has no access to commission data, which is the structural reason it cannot be influenced by it. Full detail on the disclosure page.

Corrections

Specifications change without notice and we get things wrong. If something on this site is inaccurate, tell us and we will fix it and say that we did.