Year two onward: the glass is already yours, so it is liquid only — about 1,130ml at the 500ml refill rate of ₹7.00 a millilitre, roughly ₹7,900.
The obvious way: six reeds and new bottles every time — 13 bottles at ₹1,249 = ₹16,237. That is ₹78 a room-week against ₹38.
2. The same four rooms done the obvious way cost ₹16,237. Six reeds in every bottle and a new bottle each time it empties. A 130ml runs 14–18 weeks on six reeds; take the middle at sixteen. 52 ÷ 16 = 3.25 bottles a year per position, so four positions is thirteen bottles, and 13 × ₹1,249 = ₹16,237. That is ₹78 a room-week — the same ₹78 figure you see quoted for a single 130ml, which is the point: nothing about owning four bottles is cheaper per room than owning one.
3. Lever one is reeds, and it costs nothing. Reed count sets strength and speed together. Six reeds is a hall setting; four is a bedroom setting; three suits a small bathroom. As a working approximation the reeds and the weeks trade off against each other — six reeds for sixteen weeks, four for around twenty-four, three for around thirty-two. At four reeds, 52 ÷ 24 = 2.17 fills a year per position, so four positions is about 8.7 fills instead of thirteen. You have cut the annual liquid by a third by taking two reeds out.
4. Lever two is refills, and it costs ₹2,399. Work in millilitres and the ladder is unambiguous: a 50ml at ₹749 is ₹15.00 a millilitre, a 130ml at ₹1,249 is ₹9.60, a 300ml refill at ₹2,399 is ₹8.00, and a 500ml at ₹3,499 is ₹7.00. Buying 1,130ml a year as new 130ml bottles costs about ₹10,829; buying it as 500ml refills costs about ₹7,889. The glass, the collar and the reeds were always the durable part — and refilling is the natural moment to fit fresh reeds, since clogged fibre is the commonest reason throw fades.
5. And the cheapest lever of all is owning three, not four. Three positions on four reeds is 2.17 × 3 × 130 = about 846ml a year, or roughly ₹5,900 of liquid. That is nearly ₹2,000 a year saved, and in most four-bottle homes the fourth position is a passage or a spare room — a space measured in seconds of occupancy or in visits per month. Deleting it costs nothing, saves the most, and removes a reordering line from your year permanently.
Made in India, composed by an ISIPCA Versailles-trained perfumer — and a portion of every order supports girl-child education through Nanhi Kali.
Where the annual number actually comes from
Almost everybody prices this wrongly, and in the same direction: they multiply the bottle price by four and call that the cost. Four 130ml bottles at ₹1,249 is ₹4,996, which sounds like a year of scented home and is actually about five months of one. The thing you are buying annually is not bottles. It is millilitres of oil evaporating. A 130ml on six reeds runs 14–18 weeks; take sixteen as the working middle. Fifty-two weeks divided by sixteen is 3.25 bottles a year for each position, which across four positions is thirteen bottles and 1,690ml of oil. At ₹1,249 a bottle that is ₹16,237, and at ₹78 a room-week it is exactly the per-week figure a single 130ml carries — which tells you the arithmetic is behaving.
Once you see the year as a volume of oil rather than a count of bottles, both useful levers become obvious. The first is reed count, because reeds are the only thing setting the evaporation rate. Six reeds is more evaporating surface than four, so it is a stronger room and a shorter bottle, and the trade runs roughly in proportion: about sixteen weeks on six reeds, around twenty-four on four, around thirty-two on three. Four reeds is also simply the right setting for a bedroom, so this is not a sacrifice — it is correcting two things at once. At four reeds, four positions consume about 1,130ml a year rather than 1,690ml. The second lever is what you pay per millilitre. A 50ml at ₹749 is ₹15.00 a millilitre. A 130ml at ₹1,249 is ₹9.60. A 300ml refill at ₹2,399 is ₹8.00, and a 500ml at ₹3,499 is ₹7.00. The glass, the collar and the reeds were always the durable part of the purchase, so you buy them once and buy oil thereafter. Pull both levers and the annual liquid bill falls from ₹16,237 to about ₹7,900 without a single room going unscented.
The three decisions that set your annual bill
Four reeds₹0Take two reeds out of each bottle and the four positions go from thirteen fills a year to about 8.7 — 52 ÷ 24 = 2.17 each rather than 52 ÷ 16 = 3.25. In oil, that is 1,130ml a year instead of 1,690ml. At the 500ml refill rate of ₹7.00 a millilitre it is the difference between about ₹7,900 and about ₹11,830. Nothing has been bought and nothing has been given up: four reeds is the correct setting for a bedroom anyway, and six belongs in a hall or a large living room where people arrive with a fresh nose rather than sitting in it all evening.Sizing by space — four bottles, six ways of running them
Every row is the same four rooms, run differently. The costs are annual liquid costs; year one adds ₹4,996 for the four bottles themselves. The last row is the one that saves the most.
| Space | What it needs | How many | Cost |
|---|---|---|---|
| Four 130ml, four reeds each, kept going with 500ml refills ★ | About 8.7 fills and 1,130ml a year at ₹7.00 a millilitre — ₹38 a room-week | About 1,130ml | about ₹7,900 |
| Four 130ml, four reeds each, kept going with 300ml refills | Same 1,130ml at ₹8.00 a millilitre — the smaller refill, slightly dearer per millilitre | About 1,130ml | about ₹9,040 |
| Four 130ml, six reeds each, kept going with 500ml refills | 13 fills and 1,690ml a year — the reeds, not the refill choice, are doing the damage here | About 1,690ml | about ₹11,830 |
| Four 130ml, six reeds each, a new bottle every time | 13 bottles at ₹1,249 — the obvious way, and ₹78 a room-week | 13 bottles | ₹16,237 |
| Four 50ml, six reeds each, a new bottle every time | 52 ÷ 7 = 7.4 each, about 30 bottles a year at ₹749 — bottle size is the most expensive decision here | About 30 bottles | ₹22,470 |
| The fourth position, if it is a passage or a spare room | Nothing. Three positions on four reeds is about 846ml a year — the single largest saving on this page | None | ₹0, saving ₹2,000 |
| A note on all of the above: the reed-to-weeks trade is a working approximation, not a guarantee. It is built from the stated 14–18 weeks on six reeds, and heat and airflow move it in both directions — the same bottle lasts longer in an air-conditioned bedroom than in a hot hallway. Treat every annual figure here as the right order of magnitude and your own first year as the measurement that matters. | |||
One room · the unitFrom ₹749Shop → 
Two rooms · better value₹1,498Shop → 
Large room · a switch₹1,899Shop →
Building the year, and the two levers that halve it
Start by writing the year as millilitres, once, on paper. For each position, take the bottle life at the reed count you actually run — around sixteen weeks on six reeds, twenty-four on four, thirty-two on three — and divide 52 by it. That gives fills per year. Multiply by the bottle volume and add the positions together. Four 130ml positions on four reeds comes to 2.17 × 4 × 130 = about 1,130ml; on six reeds it is 3.25 × 4 × 130 = 1,690ml. Now you have the only number that matters, and everything else is a price per millilitre. It is worth doing this in your own home rather than trusting the middle of a range, because heat and airflow move bottle life considerably: the same 130ml lasts noticeably longer in an air-conditioned bedroom than in a hot hallway, so placement changes the running cost as much as reed count does.
Then buy the litre, not the bottles. In year one you have to buy glass, because you have nothing to refill: four 130ml at ₹1,249 is ₹4,996 and supplies 520ml. Against a need of about 1,130ml that leaves 607ml to find, and two 300ml refills at ₹2,399 supply 600ml for ₹4,798. Year one totals ₹9,794, about ₹816 a month, or ₹47 a room per week. From year two the glass is yours and you are buying liquid only — about 1,130ml, most economically as 500ml refills at ₹3,499, which is ₹7.00 a millilitre and works out at roughly ₹7,900 for the year. Buy slightly more than you need rather than slightly less; unopened refill carries into the next year perfectly well, whereas a dry bottle standing in a room is the failure this whole exercise exists to prevent.
Then protect the number with three habits that cost nothing. Fit fresh reeds at every refill — clogged fibre is the commonest reason a bottle seems to fade while there is still liquid in it, and people respond by adding reeds, which makes the year more expensive rather than less. Keep every bottle out of direct sunlight and off the throw of an AC vent or fan, both of which accelerate evaporation and cost you weeks. And stagger the bottles so they do not all finish together: buying the second one a few weeks after the first is free and permanently offsets them, which turns four simultaneous reorders into four spread ones. Finally, be honest about the fourth position. If it is a passage or a room used twice a month, three positions is about 846ml a year and roughly ₹5,900 — nearly ₹2,000 saved by buying nothing at all.
What to buy
For an annual plan, only two lines of this table really matter: the 130ml you buy once and the refill you buy repeatedly. The 50ml is the expensive way to buy oil.
| Buy | What it covers | Lasts | Price |
|---|---|---|---|
| One 50ml | A single reed diffuser — a bathroom on two or three reeds — but as a way of buying oil it is ₹15.00 a millilitre, the dearest in the range | 6–8 weeks | from ₹749 |
| One 130ml ★ | The value size — each of your four positions, bought once — ₹9.60 a millilitre, and the glass is yours after that | 14–18 weeks | from ₹1,249 |
| The duo | Day & Night duo — opening two positions at once, then staggering them so all four bottles never finish in the same fortnight | 6–8 weeks each | ₹1,498 |
| Sukoon | 500ml ultrasonic — the one room over about 200 sq ft, which comes off the reed-oil budget almost entirely | Runs when you switch it on | ₹1,899 |
| 300ml refill | The running cost — every year after the first — ₹8.00 a millilitre, and ₹7.00 if you take the 500ml at ₹3,499 | Roughly 2 × 130ml fills | ₹2,399 |
Versailles
The figure people expect is four times the bottle price, and it is roughly half the truth. Four 130ml bottles is ₹4,996 and that is about five months, not a year. What you buy annually is oil, and four positions on six reeds evaporate about 1,690ml of it — thirteen bottles, ₹16,237. I would rather print that number than let anyone find it out by accident in October.
The good news is that the two things that fix it are free and cheap respectively. Take two reeds out of each bottle: the rooms are still right, four reeds is the correct bedroom setting anyway, and the year drops to about 1,130ml. Then buy refills instead of bottles, because at ₹7.00 a millilitre against ₹9.60 you are paying for glass you already own. Those two together take ₹16,237 to about ₹7,900.
And I would look hard at the fourth bottle before doing any of this. In most homes with four, one of them is a passage or a spare room, and taking it out saves nearly ₹2,000 a year for ever. Three bottles you keep filled is a better home than four you let run dry — that is not a saving line, it is the actual result. A portion of every order funds a girl's classroom through Nanhi Kali.
Frequently asked questions
- Budgeting a full year — litres, not bottles.
- Reordering with five bottles — the calendar, in days.
- Two bottles at half strength — the same weekly cost, two rooms.
- The complete sizing and quantity guide — every home type, three builds.
- Brand: the SOSA founder story.
SOSA products & prices (verified August 2026): Hotel Collection water-based ultrasonic diffuser fragrance 15ml ₹299 · 100ml ₹999 · 300ml ₹1,799 · Pack of 7 (15ml, all fragrances) ₹1,799; refills 100ml from ₹999. Seven scents: The Ritz-Carlton-inspired (white tea · bergamot · cedar), Westin-inspired (white tea · aloe · cedar), 1 Hotels-inspired (cedarwood · vetiver · green leaves), The St. Regis-inspired (amber · violet · woods), Shangri-La-inspired (jasmine · green tea · white tea), Four Seasons-inspired (citrus · floral · sandalwood), W Hotels-inspired (citrus · pepper · amber). Diffusers: Boond 300ml ₹899 · Sukoon 500ml ₹1,899 · Megh 6L ₹3,499. Water-based, phthalate-free, composed to IFRA standards for home diffusion; 3–6 drops per tank. Made in India, Pune. The Hotel Collection scents are SOSA's own interpretations inspired by the world's finest hotels; all hotel names are trademarks of their respective owners and are used only to describe the scent style — SOSA is an independent Indian fragrance house, not affiliated with or endorsed by any hotel brand. Prices and availability subject to change — see the live product pages.