SOSA · The Founder Diaries · Buying Guides
No. And output is not the reason.
A staircase void is a chimney. It moves air upward all day, which means the lower level is continuously losing fragrance and the upper level is continuously receiving someone else's. Two levels are two problems.
The honest answer to this question is no, and the interesting part is why. It is not that a machine cannot produce enough. It is that the two levels are not the same room, and a void between them guarantees they never behave alike.
The answer in 30 seconds
Can One Diffuser Scent a Duplex Apartment or Multilevel Penthouse?
- In one line. No. Plan each level separately — SOSA Vaayu ₹12,499 for the lower public run, and usually only SOSA Pawan ₹6,999 or reeds upstairs, because the upper level is already receiving air from below.₹12,499
- The short answer. Warm air rises and a staircase void gives it a path, so there is a continuous upward current between your levels. The lower level leaks fragrance; the upper level accumulates it.
- The counter-intuitive bit: the upper level usually needs less than people assume, not more. Many duplexes are over-scented upstairs and under-scented down.
- If you only do one thing: put the machine on the lower level, not at the top of the stairs, and see what reaches the landing before buying anything else.
- Never place a machine in the stairwell. Its entire output goes up and out of the room it was meant to serve.
- A single-floor penthouse is different — no void, no vertical current, and a far more predictable plan.
The answer, in full
Air in a building does not sit still, and the reason is temperature. Warm air is less dense than cool air, so it rises; cooler air moves in underneath to replace it. In a single-storey flat this produces gentle, roughly contained circulation within each room. In a home with two or three levels joined by an open staircase, it produces something much more directional, because the void is a dedicated vertical path and the current through it runs continuously. Building engineers call this the stack effect, and in a duplex it is strong enough to govern your entire fragrance plan. Two consequences follow, and they are both the opposite of what people expect. First, the lower level is not a sealed volume — it is the bottom of a column, and whatever fragrance you release there is being drawn steadily upward and away. A machine sized correctly on paper for the lower floor's cubic volume will under-deliver, because it is also quietly supplying the stairs. Second, the upper level is receiving that migrated fragrance for free, all day, and a machine placed there adds to an already-supplied space. This is why so many duplexes end up in the same odd state: faint downstairs where everyone actually sits, and faintly too much upstairs on the landing and in the bedroom nearest the stairs. The owner concludes they need a bigger machine, buys one for the lower floor, and now the upper floor is distinctly overdone. The right approach is to stop treating the home as one space with a coverage requirement and start treating it as two zones with a known flow between them. Place the main machine on the lower level, well away from the stairwell so its output serves the room rather than the void. Then wait. Live with just that for a couple of weeks and observe what arrives upstairs on its own, because in a surprising number of homes the answer is enough. If the upper level still needs something, it will usually need a small, timed, room-specific amount — a Pawan in the master, or reeds in the smaller rooms — rather than a second large unit. A portion of every SOSA order supports girl-child education through Nanhi Kali.
Why the usual fixes make it worse
A bigger machine downstairs
Raises the rate at which fragrance is delivered to the stairwell as well as the room, so the upper level becomes noticeably stronger while the lower level improves only slightly. You have paid more and widened the imbalance.
A machine at the top of the stairs
The worst available position. The void is the path of least resistance in the entire home, and a unit beside it loses most of its output into the column rather than the landing.
Two large machines, one per level
Works, in the sense that both levels are scented, but it ignores the free upward supply and almost always results in an overdone upper floor and a running cost nobody needed. Try one machine and a fortnight of observation first.
Scenting the stairwell itself
The stairwell is a passage people cross in seconds and a conduit the rest of the time. It does not reward direct treatment, and anything you put there is really being released into whichever level the current is heading towards.
How to plan a multilevel home
| Level or space | What I would do |
|---|---|
| Lower public run | SOSA Vaayu ₹12,499, or ₹12,999 hotel-inspired, placed away from the stairwell. This is where the plan starts and often where it ends. |
| The staircase void | Nothing, ever. It is a conduit, not a room, and anything placed in it is released into the level the current is going to. |
| Upper landing | Nothing at first. It is the most heavily supplied space in the home by migration alone. Assess after a fortnight. |
| Upper master bedroom | SOSA Pawan ₹6,999 on a timed window, with the door shut. The closed door is what makes it independent of the void. |
| Upper secondary rooms | Reeds. Small, enclosed, irregularly occupied — the exact conditions reeds suit. |
| Three levels | Plan downward from the top, not upward from the bottom. The highest level accumulates most and usually needs least. |
“A stairwell is not a room you can scent. It is a chimney you have to plan around.”
The method
- Treat each level as a separate zone and calculate their volumes separately.
- Place one machine on the lower public level, far from the stairwell.
- Wait a fortnight and note what arrives on the upper landing unaided.
- Only then decide whether the upper level needs anything.
- If it does, use a room-specific timed unit behind a closed door, not a second large machine.
- Never put anything in the void, and judge the result from inside the lower level, arriving from outside.
SOSA for Pune homes
Start downstairs. Let the stairs do the rest.
In most duplexes the upper level is already supplied. One machine placed well beats two placed hopefully.
SOSA Pawan ₹6,999 · SOSA Vaayu ₹12,499, ₹12,999 hotel-inspired · waterless refill oils ₹1,049 for 100 g, ₹1,849 for 300 g
View SOSA VaayuView SOSA PawanQuestions, answered
Can one diffuser cover both floors of a duplex?
Why is my upstairs stronger than my downstairs?
Where should the diffuser go in a duplex?
Does this apply to a single-floor penthouse too?
What about a double-height living room without a second floor?
How do I plan a three-level penthouse?
If you would rather ask a person
Send me the section, not just the plan
Tell me where the stairs land on each level and how open the void is, and I will tell you which level to equip and which to leave alone. A portion of every SOSA order supports girl-child education through Nanhi Kali.
Write to SOSA on WhatsApp