A 45 g cotton sachet for a sealed 1.8 m2 wardrobe that never vents

There is no diffusion in a wardrobe, only accumulation

Concentration in a sealed space is set by the ratio of release to volume; diffusion does not enter into it. A 1.8 m2 wardrobe at 2.4 m holds about 4.3 m3 — 86 times the volume of the drawer sachet plan — but whatever is released into it stays there indefinitely. That is why the dose comes down hard: the entryway plan runs an 18% load and this one runs 11%.

The test changes with the space. It is not "you can smell it when the doors open"; it is "you notice it for the first four seconds after the doors open and then stop". A wardrobe that reads continuously while the doors are open is already overdosed.

Hanging above the rail, clear of the clothes

Hang the sachet 10 cm above the rail. Below the rail, among the clothes, is the commonest mistake: garments press against the sachet and block the release face, and wool and silk sit in direct contact with oil. Silk is the worst case — once oil has wicked into it, there is no reliable way to get it out.

The inner face of the door is the alternative. It keeps the farthest distance from the clothes when shut, 25 to 40 cm in most wardrobes, but it is also the first thing the air meets when the door opens, so the read is slightly front-loaded.

Forty-five grams, 11% load, 52 days

Cotton wadding holds less oil than silica, which is exactly why it suits a sealed space: lower loading, slower release. The nominal window is 1250 hours, and because the wardrobe is shut most of that time the measured life is 52 days.

One refresh works. Add 1 ml of the same direction, shake, and leave four hours. Past the second refresh the wadding's oil retention drops sharply and the output becomes a heavy first day followed by nothing, at which point the sachet is replaced whole.

Why a woody direction suits a wardrobe specifically

Clothes are exposed continuously. Citrus and floral molecules that settle into cotton oxidise over two to three weeks and develop a sweet, stale note; woody and dry-herbal directions largely keep their shape. That is the reason this plan runs dry woody rather than the citrus direction that reads "cleanest" in the shop.

The second reason is carry-over. Whatever is in the wardrobe goes out with the wearer and stays with them all day. Woody directions change little at body temperature, while powdery and citrus directions turn noticeably sweeter.

Cost: CNY 13 a month

A 45 g sachet costs CNY 13 and lasts 52 days, which is about CNY 8 a month. A single refresh stretches it to roughly 75 days, bringing the figure down to about CNY 7. A ribbon loop is a one-off CNY 3 and lasts indefinitely. The measured total including one refresh is CNY 13 a month.

Diagnosis

• Overpowering when the doors open. Load above 14%, or the sachet is buried in the clothes. Move to an 11% load above the rail.
• Nothing at all. Cotton wadding releases very slowly in a sealed space and needs waking. Take it out into open air for two hours and put it back; output recovers for a while.
• Oil marks on a garment. Contact. Check the loop length and keep a minimum 5 cm clearance.
• A sweet, stale note. A citrus or floral direction was used. Wardrobes should only ever hold woody or dry-herbal directions.

Assembly, in order

1. Pick the filler for the room — Vermiculite holds its release when the air is damp; silica beads pull moisture in and go quiet. Between a bathroom and a wardrobe the same pouch behaves like two different products.
2. Place it side-on, never flat — Stand the pouch against a side wall or hang it. Lying flat on a drawer floor, the lower face is against the wood and half the surface does no work at all.
3. Squeeze it once a month — Squeeze the pouch once a month to break up the filler. It costs nothing and it is the difference between an even curve and a flat final fortnight.
4. Refresh twice, then replace — Add one to two millilitres of oil, close the pouch in a bag and shake for a minute. After the second refresh the filler stops holding and the whole pouch should be replaced.

Code SACH · very large surface area to volume ratio, so output is low per gram but extremely even

What it costs to keep running

Running cost	CNY 13
One fill lasts	52 d
Refill cycle	52 d
Coverage	2 m2
Refill and replacement	45 g cotton-wadding sachet, tight-weave outer, ribbon loop

Failure diagnosis for L1

What you notice	What caused it	What to change
Nothing at all, even with your head inside the wardrobe	The filler has gone flat, or the pouch is lying flat against the wood and half its surface is doing nothing	Squeeze or re-oil the filler and stand the pouch side-on. A flat pouch in a sealed volume loses about a third of its output.
It reads while you are still in the doorway	Too many units for a 1-5 m2 volume. Two carriers in one wardrobe is the usual version of this.	Take one unit out and leave the door open for an hour. Judge again the next day, not the same evening.
A sharp patch right beside the carrier	Neat oil has landed on the filler, or something is being held within the near field	Replace the filler. Nothing dilutes in place, and moving an L1 carrier into an open room does not fix a concentration problem.

Same room, other rung

• A 45 g fibre plaque for the coat end of a 1.8 m2 wardrobe (L2 · 62 d)

Open the rung card — L1 · Barely there

This record went live on 2026-10-08. Records dated later in the register are not listed anywhere on the site until their date arrives.