Per room: two 50ml at ₹1,548 = ₹774 per space. One 130ml at ₹1,249 covers one space only.
Over a year, one room: three 130ml = ₹3,747 for about 48 weeks; seven 50ml = ₹5,243 for about 49. That is ₹1,496 a year, in a single room.
2. For two rooms: no, and it is not close. Two 50ml bottles cost ₹1,548 together, or ₹1,498 as the Day & Night duo, and they scent two separate air spaces — ₹774 or ₹749 a room. One 130ml at ₹1,249 scents one. A bottle cannot serve a room it is not standing in, so the per-week figure is irrelevant to the second room: it does not exist as an option. Value comparisons only work between things that do the same job.
3. Over a year, in one room, the gap is ₹1,496. To keep a single room scented continuously you need about fifty-two weeks of running time. Three 130ml bottles give you roughly forty-eight weeks for ₹3,747. Seven 50ml bottles give you roughly forty-nine weeks for ₹5,243. The difference is ₹1,496 a year in one room — and if you have three rooms scented that way, the same decision is worth about ₹4,500 a year.
4. Refills widen it further. The glass bottle and collar are the durable part of a reed diffuser. Buy one 130ml at ₹1,249, then a 300ml refill at ₹2,399 which fills it roughly twice, and you have about forty-eight weeks of one room for ₹3,648 — about ₹76 a week. The 50ml route has no equivalent, because you would be buying seven bottles of glass you already own. This is where the real saving sits, and it only becomes available once you own the larger bottle.
5. And the two cases where the 50ml is still right. First, trying a blend. ₹749 to find out whether you want eighteen weeks of a scent is a sensible piece of insurance, and it is why the 50ml exists. Second, a short run you do not want to extend — a room prepared for a month of guests, or a seasonal scent you would rather not still be smelling in March. In both cases the 130ml's extra weeks are not a saving, they are surplus.
Made in India, composed by an ISIPCA Versailles-trained perfumer — and a portion of every order supports girl-child education through Nanhi Kali.
The two denominators, worked out
Start with the per-week figure, because it is the one that holds up. The 50ml runs 6–8 weeks on six reeds and costs ₹749 to ₹849 depending on the blend; the 130ml runs 14–18 weeks and costs ₹1,249 to ₹1,349. Taking the middles: seven weeks for ₹749 is about ₹107, and sixteen weeks for ₹1,249 is about ₹78. You are paying a 67 per cent higher price for about 130 per cent more running time, which is why the larger bottle comes out roughly a quarter cheaper per week. The ratio is stable across the range — Mountain Breeze at ₹849 and ₹1,349 lands in almost the same place — and it survives changes in reed count, because running four reeds instead of six extends both bottles by a similar proportion.
Now the other denominator, which is where most of the money is actually decided. A reed diffuser serves the air space it stands in and nothing beyond it, so the number of bottles you own sets how many rooms are scented, and the size of them sets only how often you reorder. Two 50ml bottles at ₹1,548 cover two rooms at ₹774 each; one 130ml at ₹1,249 covers one room at ₹1,249. If your home has two doors you shut in the evening, the per-week comparison is not just unhelpful, it is misleading — it will talk you into buying more weeks in a room that already had enough of them, while a second room stays bare. The correct order of questions is: which spaces deserve a bottle at all, then how many weeks I want each one to run for, then which size delivers those weeks most cheaply. Value arithmetic belongs at step three, not step one.
Three ways to read the value
130ml₹1,249Sixteen weeks for ₹1,249 is about ₹78 a week of use. Seven weeks for ₹749 is about ₹105. The larger bottle is roughly a quarter cheaper for every week it runs, and it also cuts your number of purchases from about seven a year to about three. That second effect is worth more than people expect: reordering is the part of home fragrance that actually lapses, and a bottle you forget to replace is scenting nothing at ₹0 a week — which is not the kind of saving anybody wants.Sizing by space — which format is genuinely better value where
The value question answered per space rather than in the abstract. One row costs nothing at all, and one row is the only place in the range where a 130ml is poor value.
| Space | What it needs | How many | Cost |
|---|---|---|---|
| A bedroom you sleep in every night, all year ★ | One 130ml, refilled — about ₹76 a week and three touchpoints a year instead of seven | One 130ml | from ₹1,249 |
| Two bedrooms behind their own doors | Two bottles, because a second room cannot be bought with weeks. The duo is ₹749 a room | Two 50ml | ₹1,498 |
| A room you want scented for one month only — guests, a season | One 50ml. The larger bottle's extra weeks are surplus here, not savings | One 50ml | from ₹749 |
| A small bathroom on two or three reeds | Either — and a 130ml run on two reeds is the cheapest per week of anything in the home, if you can live with one scent for that long | One | from ₹749 |
| A blend you have never smelt in your own home | One 50ml as insurance. ₹749 to find out is cheaper than ₹1,249 to find out | One 50ml | from ₹749 |
| A guest room used twice a month, or a store room | Nothing. Sixteen weeks of fragrance nobody is present for is ₹1,249 at an infinite cost per person | None | ₹0 |
| A note on all of the above: the annual figures are three 130ml at ₹1,249 = ₹3,747 for about 48 weeks, seven 50ml at ₹749 = ₹5,243 for about 49 weeks, and one 130ml plus a 300ml refill = ₹1,249 + ₹2,399 = ₹3,648 for about 48 weeks. All longevity figures assume six reeds in a closed room of standard height. | |||
One room · the unitFrom ₹749Shop → 
Two rooms · better value₹1,498Shop → 
Large room · a switch₹1,899Shop →
Reeds, refills and making the weeks last
Reed count changes the per-week figure more than the blend does. Six reeds is full strength and the basis of every longevity figure quoted here. Four reeds in a bedroom will take a 130ml past eighteen weeks, which quietly drops the cost per week below ₹70 — and produces a level most people actually prefer to sleep in. That is the rare case of the cheaper setting also being the better one. It is still a trade rather than a free upgrade: fewer reeds means less presence as well as slower consumption, so start at four, wait forty-eight hours for the reeds to saturate, and add one if a visitor cannot detect it from the doorway.
Refills are where the value argument stops being marginal. A 300ml refill at ₹2,399 fills a 130ml roughly twice — about thirty-two weeks for ₹2,399, or about ₹75 a week — and a 500ml at ₹3,499 goes further again. There is no equivalent economy in the 50ml route, because every ₹749 you spend there includes another glass bottle and collar you already own two of. If you keep two or three rooms scented permanently, moving to refills is worth more than any decision about which blend or which size, and it is the point at which a fragranced home stops feeling like a recurring purchase.
And protect the weeks you have paid for. Evaporation rises with heat and airflow, so the same bottle runs measurably shorter in a hot hallway than in an air-conditioned bedroom — placement is a running-cost decision as much as a scent one. Keep bottles out of direct sunlight, which fades fragrance and warms the oil, and out of the direct path of an AC vent or fan, which empties them fast while pushing everything against one wall. Keep them off polished wood and out of reach of children and pets. When throw drops after a few months, replace the reeds rather than the liquid: clogged fibre is the usual cause, and fresh reeds cost nothing when they come with your next bottle or refill.
What to buy
The same range read as a value ladder, from the cheapest way to try something to the cheapest way to keep a room running all year.
| Buy | What it covers | Lasts | Price |
|---|---|---|---|
| One 50ml | A single reed diffuser — a blend you have not tried, or a room you want scented for one month rather than four | 6–8 weeks | from ₹749 |
| One 130ml ★ | The value size — any room you intend to keep scented continuously — about ₹78 a week against about ₹105 | 14–18 weeks | from ₹1,249 |
| The duo | Day & Night duo — two rooms at ₹749 each, which is the cheapest per-room figure in the range | 6–8 weeks each | ₹1,498 |
| Sukoon | 500ml ultrasonic — one air space too large for a passive source, where the value question is coverage rather than cost per week | Runs when you switch it on | ₹1,899 |
| 300ml refill | The running cost — the cheapest week of home fragrance available — about ₹75, and only once you own the 130ml | Roughly 2 × 130ml fills | ₹2,399 |
Versailles
I will give you the number honestly: the 130ml is about a quarter cheaper per week and I would rather you bought it. But I have watched people take that number and buy a second 130ml for a room they sit in twice a month, because it was "better value". Value per week only counts if you want the weeks. The cheapest bottle in the world is expensive in an empty room.
The 50ml is not a worse product, it is a different job. It is what I would buy to find out whether I like a blend before living with it for four months, and it is what I would buy for a room I want scented in December and not in March. If somebody tells me they want to try Fresh Brew, I do not want them spending ₹1,349 to discover that coffee and vanilla is not what they want in their bedroom.
Where I do push is refills. One 130ml and a 300ml refill is ₹3,648 for the better part of a year in one room, and once people see that figure they stop asking about bottle sizes altogether. It is the most useful piece of arithmetic we have, and it costs us the sale of six bottles of glass. A portion of every order funds a girl's classroom through Nanhi Kali.
Frequently asked questions
- Two 50ml or one 130ml? — the room-count version of this question.
- If you can only buy one bottle — continuity beats coverage.
- The real cost per week — the same figures, at length.
- 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.