Your Cap's Wash Log and CO2 Estimate: How the Numbers Work

Two numbers on your passport are yours to build: washes logged and CO2 saved. The wash log is a tap after each wash. The CO2 figure is an estimate built from two constants: about 30 g of CO2e for one disposable cap, and about 2.25 g for one shift in a reusable one. Neither is a certified measurement, and the passport says so on the page. This guide shows the working.

Last updated: 6 September 2026

The wash log

Once you've claimed your cap, activate wash tracking and tap I just washed it after each wash. The passport accepts one log per cap per day, keeps a history of the most recent twenty, and adds the count to the cap's timeline. Alongside it you can save a wash plan: the temperature you use and whether you tumble or line dry. Stay within the temperatures on the care guide (60°C for NHS workwear, 90°C at the very most) and the cap keeps going for years.

Why bother? Two reasons. For you, it's a running record of the cap's life that carries through to the lifetime summary when you eventually retire it: days in service, washes logged, disposables avoided. For us, it's the first real data on how caps wear in different settings, at different temperatures, tumble dried or not, and that feeds back into how we make them. It's optional and it's for illustration only. Hospital and team orders can use the same log for laundering records, which is covered in the guide for procurement and auditors.

The CO2 estimate: what goes in

The estimator asks two things: how many disposable caps you'd otherwise use per shift, and how many days a week you work. It then compares two manufacturing footprints.

• One disposable cap: about 30 g CO2e. A paper and polymer blend, made, shipped and binned after one wear.
• One shift in a reusable cap: about 2.25 g CO2e. The footprint of making the cap (raw cotton, dye, energy in the workshop, freight, end of life) spread across the shifts it serves.

The reusable figure is calibrated to our published reusable-versus-disposable comparison, which puts a four-cap set covering a full-time clinical year at roughly 0.53 kg CO2e. Divide that by the shifts in a year and you land on 2.25 g. The disposable figure sits in the range of published textile lifecycle studies, but we don't hold a verified cradle-to-grave figure for single-use surgical caps, so the comparison is indicative rather than exact. The passport labels the cap figure as Scope 1, 2 and 3 of manufacture so anyone quoting it knows what's in.

What's left out, on purpose

Washing. It isn't counted on either side. A 60°C wash with the rest of your uniform, line dried, has a very different footprint from a cap-only hot wash and a tumble dryer, and we'd be guessing. Leaving it out keeps both sides on the same basis, the cost of making the thing. It also means the reusable side is missing its laundry footprint, which is exactly why we call the result indicative and why the true comparison in your setting depends on how you launder. Wash with the rest of your load and the gap stays wide; that's the practical takeaway.

A worked example

One disposable per shift, five days a week:

• Disposables avoided: 260 a year
• Disposable footprint: about 7.80 kg CO2e a year
• Reusable footprint (cap only): about 0.58 kg CO2e a year
• Estimated saving: about 7.21 kg a year, or about 21.64 kg over three years
• Roughly 13 times lower than disposables

Two disposables per shift doubles the disposable side and the saving becomes about 15 kg a year. Three days a week and it's about 4.3 kg. Play with the inputs on your own passport; the maths is the same for every cap.

What it looks like across a team

Group orders get one more figure: what the whole team has saved to date. It uses the same two constants and deliberately cautious assumptions: one disposable avoided per shift, five shifts a week, counted from the day each person's first cap was ordered, and every wearer charged the full reusable footprint even if they only have one cap. Extra caps in a rotation don't multiply the saving, because a person still wears one cap per shift. If anything the number understates it.

How to quote it

Say what it is: an estimate of manufacturing CO2e, washing excluded, from a stated per-cap model, not a certified lifecycle assessment. That's how the passport words it, and it's how we'd want it repeated in a sustainability report. If your organisation needs the assumptions written up, ask us.

The short version

• Wash log: one tap per day after each wash, plus your wash plan. Optional, for illustration, and useful to us.
• CO2 estimate: about 30 g per disposable against about 2.25 g per shift for a reusable, manufacturing only, washing excluded on both sides.
• Full-time, one disposable a shift: about 7.2 kg CO2e saved a year, roughly 13 times lower.
• Quote it as an estimate with the method stated, never as a certified figure.

More help

Our wider footprint and what we're doing about it is on the sustainability promise page. For the wash itself, how to wash your scrub cap covers NHS temperatures and frequency, and the care guide has the full drying and storage detail. Not claimed your cap yet? Here's how.