★ SOSA Vaayu · how long the oil lasts
There are five different questions hiding inside "how long does the oil last", and only one of them has a specification behind it
★ ★ ★ ★ ★
★★★★★
"Ours went about eleven weeks, not thirteen, because we run it hard in a double-height room. Knowing the range beforehand meant it was not a disappointment."
Villa · double-height living
★★★★★
"The distinction between how long a tank lasts and how long the whole supply lasts is the one that mattered to me. They are the same thing here and nobody else says so."
Vaayu ₹11,999
★★★★★
"We stretched a fill past four months by dropping one intensity step and running eight hours instead of round the clock. The room reads the same."
Heritage homestay
★★★★★
"I asked SOSA about refills before buying, exactly as this page says to. Straight answer, no salesmanship. Bought with open eyes."
Villa owner
★★★★★
"The storage advice for the unopened bottles is not something I had thought about. Cool, dark and capped, like any perfume."
Farmhouse · open plan
★★★★★
"Being told the specification does not say how many hours a day it assumes was worth more to me than a confident wrong number."
Two-floor duplex
★★★★★
"Ours went about eleven weeks, not thirteen, because we run it hard in a double-height room. Knowing the range beforehand meant it was not a disappointment."
Villa · double-height living
★★★★★
"The distinction between how long a tank lasts and how long the whole supply lasts is the one that mattered to me. They are the same thing here and nobody else says so."
Vaayu ₹11,999
★★★★★
"We stretched a fill past four months by dropping one intensity step and running eight hours instead of round the clock. The room reads the same."
Heritage homestay
★★★★★
"I asked SOSA about refills before buying, exactly as this page says to. Straight answer, no salesmanship. Bought with open eyes."
Villa owner
★★★★★
"The storage advice for the unopened bottles is not something I had thought about. Cool, dark and capped, like any perfume."
Farmhouse · open plan
★★★★★
"Being told the specification does not say how many hours a day it assumes was worth more to me than a confident wrong number."
Two-floor duplex
✓ Vaayu · 400ml tank · 90+ days a fill at mid intensity · adjustable intensity · timers ✓ Every duration figure here is arithmetic on the specification, not a measurement ✓ No separate Vaayu refill oil is sold today — confirm with SOSA before you buy
Founder Diaries · Large-Space Scenting · Oil Duration
The honest range: run gently on a short timer and a fill can comfortably exceed four months; run hard in a volume near the 1000m³ rating and it will fall well short of ninety days. Both are the machine working correctly.
Five different "lasts": a tankful, the whole in-box supply, one 100ml bottle, the scent's persistence in the room after the machine stops, and how long a sealed bottle keeps. They have five different answers.
The constraint: no separate Vaayu refill oil is sold at present, so a tankful and your entire supply are currently the same 400ml. Ask SOSA before you buy.
Vaayu₹11,999 · 400ml in the boxFor most appliances these two durations are miles apart — a tank of petrol is not the same as a lifetime of petrol, because there is a filling station. Here they coincide, because SOSA does not currently sell a separate Vaayu refill oil. The box contains four 100ml bottles, 400ml in total, which is precisely one tankful. So when you ask how long the oil lasts, today the answer is also how long your fragrance lasts before you need to have a conversation with SOSA about what comes next. I state this plainly rather than burying it because I think a reader who knows this before spending ₹11,999 is far better served than one who discovers it in month four. Ask about current refill availability at the point of purchase.
Vaayu · 90+ days a fill₹11,999Shop → 
Sukoon · 16–18 hrs a fill₹1,899Shop → 
Morning Freshness · 14–18 weeks at 130mlfrom ₹749Shop →
SOSA Vaayu specifications (verified from the live product page, August 2026): ₹11,999 (the product page displays a rounded ₹12,000). Waterless cold-air nebulisation — pressurised air atomises undiluted fragrance oil into a dry nano-mist; no water, no heat, residue-free. Coverage up to 1000m³, about 2,000–3,000 sq ft. 400ml refillable tank, 90+ days per fill at a mid intensity setting. Bluetooth app plus onboard buttons, 1h / 4h / 8h / 24h timers, adjustable mist intensity, auto-stop and key-lock. Under 38 dB. DC 12V / 1A, 5W. 165 × 80.5 × 215 mm, 0.9 kg, black or white. Freestanding or wall / HVAC mount. CE, RoHS and SGS certified. Ships with four SOSA Hotel Collection fragrances at 100ml each (400ml in total) in one of three combos chosen at checkout. SOSA does not currently sell a separate Vaayu refill oil; the 400ml supplied in the box is the fragrance available at the time of writing, and buyers who need long-term supply should confirm current refill availability with SOSA before purchasing. The cold-air oil supplied with the Vaayu is a different product from the water-based Hotel Collection sold for ultrasonic machines (15ml ₹299 · 100ml ₹999 · 300ml ₹1,799), which must not be used in a Vaayu despite sharing scent names. Other SOSA machines: Boond 300ml ₹899 (~150 sq ft) · Sukoon 500ml ₹1,899 (270–320 sq ft) · Megh 6L ₹3,499 (~215 sq ft — a runtime and humidity machine, not a coverage upgrade) · Aangan ₹25,999 (~8,000–10,000 sq ft) · Meenar ₹38,500 (12,000–18,000 sq ft) · Safar car diffuser ₹3,999. Reed diffusers 50ml ₹749–₹849 (6–8 weeks) · 130ml ₹1,249–₹1,349 (14–18 weeks) · duo sets ₹1,498–₹1,598 · oil-only refills 300ml ₹2,399 / 500ml ₹3,499. Runtime, consumption and coverage figures are manufacturer specifications and vary with intensity setting, run hours, ceiling height, ventilation and season; any per-month or per-day figure in this guide is arithmetic on those specifications, not a measurement. Electricity costs vary by state tariff. No claim is made that scenting affects ratings, reviews, bookings, occupancy, revenue, health, mood or air quality. Free shipping above ₹499. A portion of every order supports girl-child education through Nanhi Kali. Prices subject to change — see the live product pages.
The specification says 90+ days per fill on a 400ml tank, and that figure is honest — but it is a reference point taken at a mid intensity setting, and treating it as a promise is how people end up disappointed at week ten. The real answer is a range, and the range is wide enough to matter. Before the arithmetic, the thing I insist on saying at the top of every Vaayu running-cost page: SOSA does not currently sell a separate Vaayu refill oil. The 400ml in the box — four Hotel Collection cold-air fragrances at 100ml each — is the whole supply available today, which makes "how long does it last" a question about your entire fragrance budget rather than about one tankful. If long-term supply matters to you, please confirm current refill availability with SOSA before spending ₹11,999.
Quick answers — read this first
The specification: 400ml, 90+ days per fill, at a mid intensity setting. That is roughly 4.4 ml a day, or a third of the tank a month.The honest range: run gently on a short timer and a fill can comfortably exceed four months; run hard in a volume near the 1000m³ rating and it will fall well short of ninety days. Both are the machine working correctly.
Five different "lasts": a tankful, the whole in-box supply, one 100ml bottle, the scent's persistence in the room after the machine stops, and how long a sealed bottle keeps. They have five different answers.
The constraint: no separate Vaayu refill oil is sold at present, so a tankful and your entire supply are currently the same 400ml. Ask SOSA before you buy.
The short answer
Short answer: a full 400ml tank in a SOSA Vaayu is specified to last 90+ days at a mid intensity setting, which is about 4.4 ml a day. In practice a gently set machine on an eight-hour timer will run considerably longer than that, and a machine set high in a volume near the top of its 1000m³ rating will run considerably shorter. Plan on the range, not the headline, and measure your own rate over a fortnight if you need precision.
Why the range is wide: the intensity control changes how much undiluted oil is atomised per cycle and the timer changes how many hours a day the machine runs at all. Between them they can easily move a tank's life by a factor of two or three in either direction. Nothing about that is a fault — an adjustable machine has an adjustable consumption rate by definition.
Shop: Vaayu ₹11,999 — 400ml tank, up to 1000m³, adjustable intensity, 1h / 4h / 8h / 24h timers, auto-stop, key-lock, under 38 dB, 5W. If you want a fragrance with a long, fully priced life instead, a 130ml reed diffuser from ₹1,249 runs 14–18 weeks. Free shipping above ₹499.
In this guide
Specified at mid intensity
Vaayu · 400ml · 90+ days
16–18 hrs a fill
Sukoon 500ml · ₹1,899
14–18 weeks a bottle
Reed diffusers · from ₹749
Straight answer
How long does a tank of oil really last in a cold-air diffuser?
1. The specified figure, and where it comes from. A 400ml tank, 90+ days per fill, at a mid intensity setting. Divide and you get about 4.4 ml a day — a third of the tank a month, or a tenth of it every nine days. That is the baseline against which everything else is measured.
2. The plus sign is doing real work. "90+" is not marketing hedging; it reflects that a machine set below the mid step, or run on a four- or eight-hour timer rather than continuously, genuinely goes longer. Owners running a modest evening schedule in a moderate volume routinely get past four months on a fill.
3. It can also fall well short, and that is not a defect. A volume near the top of the 1000m³ rating, set high, running long hours, will use the tank faster. If you are scenting a villa ground floor and a stairwell at a firm intensity, plan for two months rather than three and be pleasantly surprised if you do better.
4. The specification does not state the daily run hours it assumes. That matters, because it is what stops anyone converting the figure cleanly into millilitres per hour. If ninety days assumes continuous running, the rate is about 0.19 ml an hour; if it assumes an eight-hour day, it is about 0.56 ml an hour. Ask SOSA which is intended if your planning depends on it.
5. A tankful and your whole supply are currently the same thing. SOSA does not sell a separate Vaayu refill oil at present. The four 100ml bottles in the box are 400ml — exactly one tank. So the honest answer to "how long does the oil last" is, today, also the answer to "how long does my fragrance last".
6. Never substitute. The water-based Hotel Collection at ₹299 / ₹999 / ₹1,799 is made for ultrasonic machines. It shares scent names with the cold-air oils and it is not the same product. It does not go in a Vaayu, and reed oil goes in neither.
7. Measure rather than trust, if it matters. Mark your tank level, run your intended schedule unchanged for a fortnight, mark it again and divide by fourteen. That millilitres-per-day figure applies to your house and nobody else's.
Made in India, CE / RoHS / SGS certified, and a portion of every order supports girl-child education through Nanhi Kali.
2. The plus sign is doing real work. "90+" is not marketing hedging; it reflects that a machine set below the mid step, or run on a four- or eight-hour timer rather than continuously, genuinely goes longer. Owners running a modest evening schedule in a moderate volume routinely get past four months on a fill.
3. It can also fall well short, and that is not a defect. A volume near the top of the 1000m³ rating, set high, running long hours, will use the tank faster. If you are scenting a villa ground floor and a stairwell at a firm intensity, plan for two months rather than three and be pleasantly surprised if you do better.
4. The specification does not state the daily run hours it assumes. That matters, because it is what stops anyone converting the figure cleanly into millilitres per hour. If ninety days assumes continuous running, the rate is about 0.19 ml an hour; if it assumes an eight-hour day, it is about 0.56 ml an hour. Ask SOSA which is intended if your planning depends on it.
5. A tankful and your whole supply are currently the same thing. SOSA does not sell a separate Vaayu refill oil at present. The four 100ml bottles in the box are 400ml — exactly one tank. So the honest answer to "how long does the oil last" is, today, also the answer to "how long does my fragrance last".
6. Never substitute. The water-based Hotel Collection at ₹299 / ₹999 / ₹1,799 is made for ultrasonic machines. It shares scent names with the cold-air oils and it is not the same product. It does not go in a Vaayu, and reed oil goes in neither.
7. Measure rather than trust, if it matters. Mark your tank level, run your intended schedule unchanged for a fortnight, mark it again and divide by fourteen. That millilitres-per-day figure applies to your house and nobody else's.
Made in India, CE / RoHS / SGS certified, and a portion of every order supports girl-child education through Nanhi Kali.
TL;DR: 90+ days on a 400ml tank at mid intensity — about 4.4 ml a day. Gentle setting and a short timer push it past four months; a high setting in a large volume brings it under two. And since no separate Vaayu refill oil is sold today, that one tank is currently your whole supply — ask SOSA about availability before you buy.
One tank, ninety-odd days, and a range around it
SOSA Vaayu · waterless cold-air nebuliser ₹11,999
A 400ml refillable tank rated at 90+ days per fill at a mid intensity setting, covering up to 1000m³ — about 2,000 to 3,000 sq ft depending on ceiling height. Pressurised air atomises undiluted oil into a dry nano-mist; there is no water and no heat, so nothing evaporates except what the machine deliberately releases. Adjustable mist intensity, 1h / 4h / 8h / 24h timers, auto-stop and key-lock, from a Bluetooth app or the onboard buttons. Under 38 dB, DC 12V / 1A at 5W, 0.9 kg. Four Hotel Collection cold-air fragrances at 100ml each in the box; no separate refill oil is currently sold, so ask SOSA before you commit.
Part one — three durations that get confused for one another
When someone writes to ask how long the oil lasts, they usually mean one of three quite different things, and answering the wrong one is how these conversations go sideways. The life of a fill, the life of your total supply, and the persistence of the scent in the room after the machine stops are three separate quantities. Only the first has a published specification behind it. The second is currently identical to the first, for a reason I will state as often as it takes. The third is not a consumption question at all and is the one people are most often actually asking.
1
DURATION ONE · SPECIFIED
The life of one fill — 400ml, 90+ days
This is the number on the product page and it is the only one with a manufacturer's figure behind it. 400ml, 90 or more days, at a mid intensity setting. The arithmetic gives 4.44 ml a day, and I would encourage you to think in tank-thirds rather than millilitres — a third of the tank a month is easier to check by eye than four and a half millilitres a day is to imagine. It also means the tank is a poor early-warning system: a change of habit that costs you a quarter of your supply will take three weeks to become visible in the glass. If you want to know your real rate, mark the level with a piece of tape on day one and again on day fourteen.
The rule of thumb: at mid intensity, one third of the tank a month. If yours is falling faster, your setting is above the specified mid.
2
DURATION TWO · CURRENTLY THE SAME
The life of your entire supply
Vaayu₹11,999 · 400ml in the boxFor most appliances these two durations are miles apart — a tank of petrol is not the same as a lifetime of petrol, because there is a filling station. Here they coincide, because SOSA does not currently sell a separate Vaayu refill oil. The box contains four 100ml bottles, 400ml in total, which is precisely one tankful. So when you ask how long the oil lasts, today the answer is also how long your fragrance lasts before you need to have a conversation with SOSA about what comes next. I state this plainly rather than burying it because I think a reader who knows this before spending ₹11,999 is far better served than one who discovers it in month four. Ask about current refill availability at the point of purchase.
The condition of purchase: if you need years of uninterrupted supply, get an answer on refills in writing before you order.
3
DURATION THREE · NOT A CONSUMPTION QUESTION
How long the scent stays in the room
A great many people asking about oil duration are really asking this: if I run it for four hours, is the room still scented at bedtime? That is persistence, not consumption, and it depends on the volume, the air exchange rate, the furnishings and the composition rather than on the tank. In a reasonably closed, air-conditioned Indian home a cold-air field established over a few hours will usually still be perceptible for some hours after the machine stops, which is exactly why running on a timer costs far less oil than continuous running without feeling proportionally weaker. In a space with windows open and a through-draught it will clear far quicker. I cannot give you a number for your house; I can tell you that the timer is a much better tool than most owners realise, and that this is the mechanism behind it.
Part two — five versions of the question, with the honest answer to each
Set out plainly, because the confusion in Part one is worth resolving in a table you can keep. Note the confidence column: only two of these five have a manufacturer's specification behind them, and I would rather flag that than let the layout imply otherwise.
Five kinds of "how long"
What you are really asking, and what can honestly be said
| The question you are really asking | What it measures | The honest answer | Confidence | How to settle it |
|---|---|---|---|---|
| How long does a full tank last? ★ | 400ml at the specified mid intensity | 90+ days · about 4.4 ml a day | Manufacturer specification | Mark the level, wait a fortnight, divide |
| How long does my whole fragrance supply last? | Everything you own, since no refill is sold | The same 90+ days — the box is exactly one tank | Follows from the supply position | Ask SOSA about refill availability before buying |
| How long does one 100ml bottle last? | A quarter of the box in the tank | About 22 days at mid intensity — call it three weeks | Arithmetic on the specification | Sequence the four bottles deliberately |
| How long does the room stay scented after it stops? | Persistence, not consumption | Hours rather than minutes in a closed AC home; far less with a draught | No specification exists — it is your room | Run a 4h timer and see when it fades |
| How long does a sealed bottle keep? | Storage life of the unopened oil | Not stated by SOSA. Keep capped, upright, cool and out of sunlight | Unverified — do not trust a number for this | Ask SOSA; store it like any fine fragrance |
| The honest caveat: only the first row has a published figure, and even that is quoted at a mid intensity setting whose daily run hours are not stated. Everything derived from it here — 4.4 ml a day, 22 days per 100ml bottle, a third of the tank a month — is plain arithmetic on the specification and not a measurement taken in any home. Real duration varies with intensity, run hours, connected volume, ceiling height, ventilation and season. And the frame around all five rows: SOSA does not currently sell a separate Vaayu refill oil, the 400ml in the box is the cold-air fragrance available at the time of writing, and the water-based Hotel Collection for ultrasonic machines is not a substitute. | ||||
Shop this guide
Three formats, three published durations
Vaayu · 90+ days a fill₹11,999Shop → Sukoon · 16–18 hrs a fill₹1,899Shop → Morning Freshness · 14–18 weeks at 130mlfrom ₹749Shop →
The SOSA principle
A specification is a reference point taken at one setting. A range is what you actually live with.
Ninety days is true at the mid step. Below it you will beat that figure; above it you will not. Publishing the range rather than the headline is the only way the number is useful to anybody.
Part three — when a fill will not reach ninety days, and what to do about it
Three situations produce a tank that empties early, and none of them is a fault. The first is a volume near the top of the rating. A machine specified for up to 1000m³ can indeed fill 1000m³, but doing so requires a higher intensity setting than a 250m³ living-dining does, and intensity is what spends oil. If your connected volume is 800 to 1000 cubic metres, plan on meaningfully less than ninety days and set your expectations accordingly at the point of purchase rather than at the point of disappointment. The second is continuous running. The 24h timer exists and some commercial installations want it, but running round the clock in a home is almost always more scenting than anyone needs; most people are asleep or out for two-thirds of it. The third is a hand on the dial. In a let property or a busy household, someone raises the intensity because a room smelt faint to them on a particular evening, and nobody ever puts it back. The key-lock exists precisely for this and costs nothing to use.
The supply position makes each of those three worth taking seriously rather than shrugging at. To repeat it once more, because it is the most important sentence in this cluster: SOSA does not currently sell a separate refill oil for the Vaayu. The 400ml supplied in the box is the cold-air fragrance available at the time of writing. There is no refill price for me to quote and I will not estimate one, nor will I direct you to the water-based Hotel Collection as a stand-in, because it is a genuinely different product built for ultrasonic machines and putting it in a nebuliser is not a saving. What I would like you to do instead is ask SOSA, before you order, whether a cold-air refill is available on the day you are buying and what the guidance is if not. If the answer does not fit your horizon, buy a Sukoon at ₹1,899 or a pair of reed diffusers from ₹1,498 with a clear conscience — both have fragrance you can buy again at a published price.
A word on the oil itself, since duration has a second meaning that nobody covers. The bottles you are not currently using are fine fragrance concentrate, and they should be kept the way you would keep any good perfume: capped tightly, standing upright, somewhere cool and dark, away from a sunny windowsill or the top of an appliance that gets warm. Heat and light are what age a composition — it is the same reason we tell reed diffuser owners to keep the bottle out of direct sun. SOSA does not publish a shelf life for the cold-air oils and I am not going to invent one, so if you are planning to hold three sealed bottles for a year, that is a question worth putting to SOSA along with the refill one. And the boundary that belongs on every page in this cluster: a scent machine adds fragrance and does nothing else. It does not purify air, remove odours, or affect anyone's health, sleep or mood.
Ninety days is what the machine does at the middle of its dial. Where you set the dial is the actual answer.
— Sonal Sahani, SOSA
Part four — what lengthens a fill and what shortens it
Seven changes, with what each does to the tank and what it does to the room. The point of the middle two columns is that almost nothing here is free — you are trading duration against presence, and the trade is worth making consciously.
The duration edit
Each lever, with what it costs you in the room
| Change | Effect on the tank | Effect on the room | My verdict |
|---|---|---|---|
| Drop the intensity one step ★ | The single biggest gain in duration | Often imperceptible after a few days | Do this first, and wait a week before judging |
| Run an 8h timer instead of 24h | Roughly a third of the oil for two-thirds of the benefit | Scent persists for hours after the machine stops | The correct default for almost every home |
| Improve the mounting position | Indirect — better placement lets you set lower | More even field, less waste into one corner | Free, and worth twenty minutes of trial |
| Close doors to zones you are not scenting | Smaller effective volume, so a lower setting works | Those rooms get nothing — give them their own source | Sensible; a shut door is a wall in both directions |
| Use the key-lock | Stops the slow creep of somebody else's adjustments | Nothing — the room is unchanged | Essential in a let property or a busy house |
| Run high in a volume near 1000m³ | Well short of ninety days. Budget for it | The reason you bought the machine, if that is your space | Legitimate — just do not expect the headline figure too |
| Give closed rooms a reed diffuser instead | Takes load off the machine entirely | Each room gets its own character | From ₹749 · 6–8 weeks, or 130ml at 14–18 weeks |
Honest notes for buyers: the 400ml tank and the 90+ days per fill are manufacturer specifications quoted at a mid intensity setting; the specification does not state the daily run hours it assumes, which is why no single millilitres-per-hour figure appears on this page. Every derived number here — 4.4 ml a day, about 22 days per 100ml bottle, a third of a tank a month — is arithmetic on the specification, not a measurement, and real duration varies with intensity, run hours, connected volume, ceiling height, ventilation and season. SOSA does not currently sell a separate Vaayu refill oil; the 400ml supplied in the box is the cold-air fragrance available at the time of writing, and buyers who need long-term supply should confirm current availability with SOSA before purchasing. The water-based Hotel Collection at ₹299 / ₹999 / ₹1,799 is a different product for ultrasonic machines and must not be used in a Vaayu; reed oil goes in neither. Shelf life of the sealed cold-air bottles, warranty length, AMC terms, spare parts and app platform details are unverified — ask SOSA. No health, mood, air-purification or odour-removal claim is made or implied. Free shipping above ₹499, and a portion of every order supports girl-child education through Nanhi Kali.
A duration you can buy again, at a published price
SOSA Morning Freshness · reed diffuser ₹749 / 50ml
If what you actually want is a fragrance with a long, knowable, repeatable life, this is the honest recommendation for a closed room. Malabar lemon over peppermint and Nilgiri eucalyptus, on an alcohol-free, phthalate-free, heat-stable CCT base with six fibre reeds; 50ml runs six to eight weeks and 130ml at ₹1,249 runs 14–18 weeks. When it ends you buy another, or a 300ml oil-only refill at ₹2,399 that keeps a vessel going eight to eleven months. Flip the reeds weekly, keep it out of direct sun and stand it on a tray. Reed oil goes in reed bottles only — never in a machine.
SS
ISIPCA
Versailles
Versailles
A note from Sonal
I have a rule about specifications that I have never regretted: publish the range, not the headline. We do it with the reed diffusers, where a 50ml is six to eight weeks rather than "up to eight", and we should do it here too. Ninety days on a 400ml tank is honest, and it is honest at one setting. A reader who takes it as a floor will be disappointed if they run a big villa at full intensity, and a reader who takes it as a ceiling will be pleasantly surprised when a modest evening schedule runs four and a half months. Both of those readers deserved the range.
The thing I want to be most careful about is the second duration, the one that is currently the same as the first. We do not sell a separate cold-air refill for this machine today. I would rather say that on every page than let it be discovered by someone in month four who has committed a signature scent to a property and now has nowhere to go. Ask us on the day you buy. If the answer suits you, buy it and enjoy it — it is a genuinely good machine and there is nothing else in our range that does what it does. If it does not suit you, do not buy it, and I will think none the worse of the decision.
Everything we make is composed and handmade in small batches in Pune, and a part of every order funds a girl's classroom through Nanhi Kali.
Frequently asked questions
How long does 400ml of oil last in a cold-air diffuser?
The SOSA Vaayu specification is 90+ days per fill at a mid intensity setting, which is about 4.4 ml a day. Set below the mid step, or run on a four- or eight-hour timer rather than continuously, and a fill will comfortably exceed that. Set high in a volume near the machine's 1000m³ rating and it will fall short. Treat ninety days as a reference point at one setting rather than a guarantee.
Why does the specification not give millilitres per hour?
Because it does not state how many hours a day the 90-day figure assumes, and without that you cannot convert cleanly. If the assumption is continuous running, 4.4 ml a day is about 0.19 ml an hour; if it is an eight-hour day, the same figure is about 0.56 ml an hour. Rather than pick one and present it as fact, I would rather you knew the ambiguity existed and asked SOSA if it matters to your planning.
What is the best way to make a fill last longer?
Drop the intensity one step and leave it alone for a week before judging — fragrance takes days to establish properly in a large volume, and impatience is the commonest cause of over-setting. After that, move from continuous running to an eight-hour timer covering the hours you are actually in the space. Between them those two changes can transform a tank's life without much changing how the room reads.
Do the unopened bottles go off?
SOSA does not publish a shelf life for the cold-air oils, so I am not going to state one. Treat them as you would any fine fragrance concentrate: capped tightly, standing upright, cool, dark, away from direct sunlight and away from anything that gets warm. If you plan to hold sealed bottles for a long period, ask SOSA for guidance at the same time as you ask about refill availability.
What happens when the 400ml is finished?
SOSA does not currently sell a separate cold-air refill oil for the Vaayu, so at the time of writing the 400ml in the box is the supply available. That makes this the question to settle before you buy rather than after. The water-based Hotel Collection for ultrasonic machines is not a substitute and must not go in a Vaayu. Ask SOSA where refills stand on the day you order.
Large-space scenting · oil duration
90+ days is the middle of the dial — plan on the range around it
The SOSA Vaayu at ₹11,999 runs a 400ml tank rated at 90+ days per fill at mid intensity, nebulising undiluted oil into a dry cold-air mist across up to 1000m³, with adjustable intensity, 1h / 4h / 8h / 24h timers, auto-stop and key-lock, under 38 dB on 5W. Four Hotel Collection cold-air fragrances at 100ml each are supplied in the box. No separate Vaayu refill oil is sold at the time of writing — confirm current availability with SOSA before you commit. Free shipping above ₹499, and a portion of every order supports girl-child education through Nanhi Kali.
See the Vaayu → Reed diffusers from ₹749
Continue the read
More on duration and running cost
- How much fragrance oil does a cold-air diffuser use? — consumption as a setting rather than a spec.
- How long can 400ml last in a scent machine? — the in-box supply at different daily run hours.
- How long does 400ml last at eight hours a day? — the one scenario, worked all the way through.
- The complete running-cost and consumption guide — this page and the eight around it, in one place.
- Brand: the SOSA founder story.
Editorial standards & sources
About this guide: Written by Sonal Sahani, ISIPCA Versailles-trained founder and perfumer at SOSA Home & Body, on how long a tank of fragrance oil lasts in a cold-air nebulising diffuser and what moves that figure in either direction. The 400ml tank and the 90+ days per fill are manufacturer specifications quoted at a mid intensity setting; the specification does not state the daily run hours it assumes, and every derived figure on this page is arithmetic on it rather than a measurement. Real duration varies with intensity, run hours, connected volume, ceiling height, ventilation and season. Shelf life of the sealed cold-air fragrance bottles is not published by SOSA and is not estimated here. No health, mood, air-purification or odour-removal claim is made or implied.SOSA Vaayu specifications (verified from the live product page, August 2026): ₹11,999 (the product page displays a rounded ₹12,000). Waterless cold-air nebulisation — pressurised air atomises undiluted fragrance oil into a dry nano-mist; no water, no heat, residue-free. Coverage up to 1000m³, about 2,000–3,000 sq ft. 400ml refillable tank, 90+ days per fill at a mid intensity setting. Bluetooth app plus onboard buttons, 1h / 4h / 8h / 24h timers, adjustable mist intensity, auto-stop and key-lock. Under 38 dB. DC 12V / 1A, 5W. 165 × 80.5 × 215 mm, 0.9 kg, black or white. Freestanding or wall / HVAC mount. CE, RoHS and SGS certified. Ships with four SOSA Hotel Collection fragrances at 100ml each (400ml in total) in one of three combos chosen at checkout. SOSA does not currently sell a separate Vaayu refill oil; the 400ml supplied in the box is the fragrance available at the time of writing, and buyers who need long-term supply should confirm current refill availability with SOSA before purchasing. The cold-air oil supplied with the Vaayu is a different product from the water-based Hotel Collection sold for ultrasonic machines (15ml ₹299 · 100ml ₹999 · 300ml ₹1,799), which must not be used in a Vaayu despite sharing scent names. Other SOSA machines: Boond 300ml ₹899 (~150 sq ft) · Sukoon 500ml ₹1,899 (270–320 sq ft) · Megh 6L ₹3,499 (~215 sq ft — a runtime and humidity machine, not a coverage upgrade) · Aangan ₹25,999 (~8,000–10,000 sq ft) · Meenar ₹38,500 (12,000–18,000 sq ft) · Safar car diffuser ₹3,999. Reed diffusers 50ml ₹749–₹849 (6–8 weeks) · 130ml ₹1,249–₹1,349 (14–18 weeks) · duo sets ₹1,498–₹1,598 · oil-only refills 300ml ₹2,399 / 500ml ₹3,499. Runtime, consumption and coverage figures are manufacturer specifications and vary with intensity setting, run hours, ceiling height, ventilation and season; any per-month or per-day figure in this guide is arithmetic on those specifications, not a measurement. Electricity costs vary by state tariff. No claim is made that scenting affects ratings, reviews, bookings, occupancy, revenue, health, mood or air quality. Free shipping above ₹499. A portion of every order supports girl-child education through Nanhi Kali. Prices subject to change — see the live product pages.