STAGE 2 · EXPLORATORY ARCHIVE ANALYSIS · VERSION 1

Shorter recorded dryer runtimes.
Less energy used.

Analysis snapshot: September 6, 2026. Measurement period: August 18–September 5, 2026. This public edition summarizes an existing archive analysis, not a new controlled experiment or peer-reviewed paper. All runs used electric hand dryers; paper-towel use was not part of this analysis.

How these observations were produced

1. Collect & develop. We first recorded dryers running, then used those recordings to develop and check the dryer-timing tool, the Flick First Dryer Verifier app.
2. Record & review. The app recorded dryer runs during flick-dry and direct-dry trials, and each run was reviewed and labelled; see Trial conditions and limitations.
3. Analyze & report. Exports were checked, repeated records removed, invalid runs excluded, and runtimes compared within sets; see Method and the per-set table below.

Dataset and accounting

14 ZIP exports contained 116 exported run records. Removing 14 exact repeated records left 102 unique runs: 49 classified for this public report as flick-dry, 47 as direct-dry, and 6 invalid measurement. The 96 valid reviewed runs enter comparisons; invalid runs are excluded.

Method

Compare conditions within archive/measurement-date sets, a provisional proxy rather than verified person/dryer identity. Do not pool individual runtimes across sets. Exact duplicate start/stop/runtime signatures were counted once and their canonical labels agreed. Legacy review labels were normalized; comments were not parsed as reviews. Public condition names are flick-dry and direct-dry; the private source labels and measurements are unchanged.

Within-set median reduction (%) = 100 × (direct-dry median − flick-dry median) / direct-dry median. Medians were checked using integer-millisecond input. Displayed seconds use half-up rounding; differences are computed before rounding displayed medians.

Trial conditions and limitations

The trial procedure below is as described by the project team; trial order, timing, and labels come from the run records.

How the trials were run

• Every trial started with freshly washed hands, rinsed the same way each time.
• Flick-dry trials flicked excess water off 12 times into the sink before drying; direct-dry trials went straight to the dryer.
• In both conditions, people stopped drying when their hands felt dry, as they would in everyday use.
• Several people took part. Within a set, flick-dry and direct-dry trials alternated: strictly in 12 of the 15 sets, and mostly in the other 3. Each set took between 1 and 15 minutes.

What each record contains

• The app records when the dryer's sound starts and stops; running time is the difference. It checks the sound about every 60 ms. This is the detection interval; overall timing accuracy also depends on detection thresholds and recorder delay, which were not measured independently.
• All 14 exports passed file-integrity and audio sample-accounting checks.
• Each run was reviewed and labelled flick-dry, direct-dry, or invalid measurement; invalid runs are excluded.

What was not controlled or recorded

• Who performed each run, and which dryer was used: the records store no person or dryer IDs, so sets are grouped by export and date instead, and a set may combine runs from more than one person.
• How much water flicking removed, and how dry hands were at the end: neither was measured. Dryness was each person's own judgement.
• Trial order: every set started with a flick-dry trial, so effects such as the dryer warming up are not balanced between the two conditions.
• Dryer power: not measured. The energy figures below use example power ratings.
• Only 12 flicks were tested; other flick counts have not been compared.

Per-set observations

Anonymous set IDs preserve the source analysis order. Exact timestamps, export filenames, raw recordings, and private records are not included in this public edition. These IDs do not establish independent participants.

Energy savings calculated from dryer running time

For a dryer operating at constant power, the percentage reduction in running time is also the percentage reduction in operating energy. The calculations below use several example power ratings to show how the observed runtime difference translates into energy saved.

Across the 15 comparison sets, the average of the within-set median differences shown in the table above is 5.631 seconds per use. Each set counts equally, regardless of how many runs it contains. The calculations below translate this time saving into energy savings at different example dryer power ratings.

Illustrative energy difference (Wh/use) = assumed power (W) × average runtime difference (s) / 3600. At an assumed 1,500 W, this yields 2.346 Wh/use. The calculation uses 1,500 W as an example dryer power rating.

• 500 W assumed: 0.782 Wh/use.
• 1,000 W assumed: 1.564 Wh/use.
• 1,500 W assumed: 2.346 Wh/use.
• 2,000 W assumed: 3.128 Wh/use.
• 2,300 W assumed: 3.597 Wh/use.

Small-sample sensitivity: Restricting to the eight sets with at least three runs per condition gives an average of the within-set median differences of 4.973 seconds. This filter does not address the limitations above or make runs independent.