Split them unevenly: more downstairs than the area suggests, fewer upstairs.
Buy nothing for the staircase. It is already carrying scent from below, and a machine on the landing is the commonest wasted purchase in a two-floor home.
2. Count the upper floor, then take one away. Bedrooms upstairs sit in air that has already been faintly scented by whatever is running below. In practice that means the landing-adjacent rooms need very little, and one Sukoon in the master often does the whole upper floor if the doors stay open during the day.
3. Buy nothing for the stairs. The staircase is the one part of a duplex that scents itself. Air moving through it carries fragrance up from the ground floor continuously — a machine standing in that column is dispersing into a draught, which is the least efficient thing a diffuser can do.
4. A double-height room counts as two. Coverage ratings assume an ordinary ceiling. A living room open to the roof at eighteen or twenty feet has roughly double the air volume of the same floor area at ten feet, so a 400 sq ft double-height space wants two Sukoons placed low, not one placed high.
5. More area always means more Sukoons. Never a Megh. It costs ₹3,499 and is rated to 215 sq ft — less area than a Sukoon, not more. Buy it for a hundred hours of runtime in one dry room, never to cover a bigger floor.
Made in India, composed by an ISIPCA Versailles-trained perfumer — and a portion of every order supports girl-child education through Nanhi Kali.
Why a duplex is not two flats stacked on top of each other
The physics is unglamorous and completely reliable. Warm air is less dense than cool air, so it rises; in a house with an internal staircase it rises through the stairwell, because that is the only continuous vertical path available. Kitchens, bodies, appliances and afternoon sun all warm the ground floor, and the resulting slow upward current runs all day without you noticing it. Fragrance molecules go along for the ride. This is why a duplex owner will tell you the upstairs landing smells vaguely of whatever is diffusing in the living room, and why the living room itself never seems to hold its scent as well as the same room would in a flat. Nothing is faulty. The house is doing what a chimney does.
Which means the arithmetic people reach for — area divided by coverage, halved between two floors — gets the split exactly backwards. The ground floor is running a permanent small deficit and needs more machines than its square footage suggests. The upper floor is running a permanent small surplus and needs fewer. In a 2,000 sq ft duplex with 1,000 sq ft per floor, an even split of two and two performs badly: downstairs reads thin, upstairs reads muddled because the bedroom scent is sitting on top of an uninvited layer from below. Three and one is the setup that works — and it costs the same.
The three decisions in a duplex
SOSA Sukoon₹1,899Start the way you would in any home: how many genuinely separate air spaces downstairs do you want to smell of something? An open living-dining-kitchen is one space, however large it looks on the plan. A closed study is a second. Then add one more Sukoon to the open area — not because the room is bigger than you thought, but because the stairwell is drawing off a share of everything you put into it. In an open ground floor with the staircase rising out of it, two machines placed well apart hold a scent that one machine cannot.The duplex sizing table
Sized by air space rather than by area, with the ground floor deliberately weighted heavier. Coverage figures assume ordinary ceiling height, a closed door and no strong draught — a double-height room, a running fan or an open stairwell all reduce what one machine achieves.
| Duplex, roughly | Ground floor | Upper floor | Machines · total |
|---|---|---|---|
| 1,500 sq ft, 2 bedrooms up | Open living-dining: 2 Sukoons | Master only: 1 Sukoon | 3 · ₹5,697 |
| 2,000 sq ft, 3 bedrooms up ★ | Open living-dining: 2 · study or guest room: 1 | Master: 1 · other bedrooms open to the landing: nothing | 4 · ₹7,596 |
| 2,500 sq ft, double-height living | Double-height living: 2 placed low · dining or family room: 1 | Master: 1 · second bedroom: 1 | 5 · ₹9,495 |
| 3,000 sq ft, 4 bedrooms up | Living: 2 · dining or family: 1 · ground bedroom or study: 1 | Master: 1 · one shared upstairs room: 1 | 6 · ₹11,394 |
| Very open ground floor above ~2,000 sq ft of connected volume | One Vaayu ₹11,999 — waterless, runs neat oil, cannot take the water-based Hotel Collection | Sukoons in the bedrooms as above | Vaayu + 2–3 Sukoons |
| Two things never to buy: a machine for the staircase or landing — it is a transit space already carrying scent from below — and a Megh as a coverage upgrade. The Megh covers 215 sq ft against the Sukoon's 270–320; it is a hundred-hour runtime and humidity machine for one dry room. For more area, the answer is always another Sukoon. | |||
Sukoon · buy three to six₹1,899Shop → 
Hotel Collection · both floorsFrom ₹299Shop → 
Boond · a small bedroom₹899Shop →
Placement, drops and when to run each floor
Downstairs, place away from the foot of the stairs. That corner is where the upward current begins, and a machine standing in it feeds the stairwell rather than the room. Put your ground-floor Sukoons on the far side of the living area from the staircase, roughly a metre off the floor, and well apart from each other. Two machines six feet apart is one machine with a stronger patch. Two at opposite ends of an open ground floor is even coverage. Keep both out of the direct throw of a fan or a split AC.
Upstairs, place low and away from the landing. This is the opposite of the instinct, and it is the right call: scent already arrives at the landing on its own, so a bedroom machine should sit as far into the room as practical, near the bed rather than the door. Drops matter more here than downstairs. Use three to four per tank on the ground floor, where you are fighting a constant loss, and two to three upstairs, because the bedroom is starting from a base of whatever came up the stairs. Six drops in an upstairs bedroom in a duplex is how people end up with a house that smells heavy rather than clean.
Schedule is the free half of the answer. Run the ground floor in the late afternoon and evening — two to three hours on a timer is plenty, and the stairwell will distribute a soft version of it upstairs by itself. Run the bedroom machines for an hour before sleep and let the auto shut-off handle the rest; a 500ml tank claims 16 to 18 hours on low, which in a home mostly means you will over-scent and get through fragrance faster than you need to. Rinse tanks when you change scents and use filtered water in hard-water cities.
What a duplex setup actually costs
Every total below is the real arithmetic, and every Sukoon in it arrives with three 15ml Hotel Collection fragrances of your choice — so a four-machine setup includes twelve bottles and needs nothing added on day one.
| Setup | What you get | Covers | Total |
|---|---|---|---|
| The minimum that works | 3 × Sukoon at ₹1,899 — 2 down, 1 up · includes 9 × 15ml scents | Duplex to ~1,500 sq ft | ₹5,697 |
| The standard duplex ★ | 4 × Sukoon at ₹1,899 — 3 down, 1 up · includes 12 × 15ml scents | ~2,000 sq ft over two floors | ₹7,596 |
| Larger or double-height | 5 × Sukoon at ₹1,899 — 3 down, 2 up | ~2,500 sq ft, tall living room | ₹9,495 |
| Fully covered | 6 × Sukoon at ₹1,899 — 4 down, 2 up | ~3,000 sq ft over two floors | ₹11,394 |
| Running cost | A 300ml bottle ₹1,799 (~₹6/ml) or a 100ml refill from ₹999 | Months across four machines | from ₹999 |
Versailles
The first duplex I sized properly was not a customer's, it was a friend's house in Baner, and I got it wrong on the first pass. I split six machines three and three, which looked balanced on paper. Downstairs was thin by nine in the evening and upstairs was cloying. We moved two machines down a floor and it fixed itself in a week.
What I had forgotten is that a house with a staircase in it is not a sealed set of rooms — it is a system with a direction. Air goes up. Everything you put into the ground floor is being slowly exported upstairs, and everything upstairs is being topped up whether it wants to be or not. Once you see the house that way, the uneven split stops feeling like favouritism towards the living room and starts feeling like the only sensible reading of the building.
So: three to six Sukoons, weighted downstairs, nothing on the stairs, fewer drops upstairs than down. Buy the machines first and the big bottle later — the scents come in the box. A portion of every order funds a girl's classroom through Nanhi Kali, which is the part of this business I am least willing to negotiate on.
Frequently asked questions
- Best floor-by-floor diffuser setup for a duplex — the itemised kit, floor by floor.
- Where to place diffusers in a duplex — the placement rules across two floors.
- Duplex home scenting budget — the full arithmetic, every total.
- Complete diffuser buying guide for duplexes — everything in one place.
- 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.