How Long Can 400 ml of Fragrance Last in a Scent Machine?

How Long Can 400 ml of Fragrance Last in a Scent Machine?

 

★ 400ml is not a duration — it is a number of running hours, and your daily schedule divides itSOSA Vaayu ₹11,999 · 400ml in the box · 90+ days a fill · no separate refill oil sold todayA portion funds girl-child education
★ SOSA Vaayu · what 400ml buys
Four hundred millilitres buys you a fixed number of running hours; how many days that becomes is a decision you make with the timer
★ ★ ★ ★ ★
★★★★★
"Converting the tank into running hours instead of days was the thing that made it planable. Two thousand-odd hours, divided by my schedule."
Rajeev N. Pune
Villa · 2,200 sq ft
★★★★★
"We run four hours a day in the common areas of a homestay. On this page's arithmetic that is a very long time from one box."
Lakshmi V. Wayanad
Homestay owner
★★★★★
"Honest about the two ways of reading the ninety-day figure. I planned on the shorter one and have been comfortably ahead of it."
Imran S. Hyderabad
Duplex · open stairwell
★★★★★
"The advice to keep two bottles sealed as a reserve until we knew our real rate was exactly right for a let property."
Shweta A. Lonavala
Weekend let
★★★★★
"I bought a Sukoon in the end because of the supply note here, and the brand still got the sale. That is how it should work."
Gopal R. Chennai
Sukoon ₹1,899
★★★★★
"Measured our own rate over a fortnight as suggested. It came out closer to the optimistic column and we stopped worrying."
Farah Q. Bengaluru
Vaayu ₹11,999
★★★★★
"Converting the tank into running hours instead of days was the thing that made it planable. Two thousand-odd hours, divided by my schedule."
Rajeev N. Pune
Villa · 2,200 sq ft
★★★★★
"We run four hours a day in the common areas of a homestay. On this page's arithmetic that is a very long time from one box."
Lakshmi V. Wayanad
Homestay owner
★★★★★
"Honest about the two ways of reading the ninety-day figure. I planned on the shorter one and have been comfortably ahead of it."
Imran S. Hyderabad
Duplex · open stairwell
★★★★★
"The advice to keep two bottles sealed as a reserve until we knew our real rate was exactly right for a let property."
Shweta A. Lonavala
Weekend let
★★★★★
"I bought a Sukoon in the end because of the supply note here, and the brand still got the sale. That is how it should work."
Gopal R. Chennai
Sukoon ₹1,899
★★★★★
"Measured our own rate over a fortnight as suggested. It came out closer to the optimistic column and we stopped worrying."
Farah Q. Bengaluru
Vaayu ₹11,999
Vaayu · 400ml in four 100ml bottles · 90+ days a fill at mid intensity Every figure on this page 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 · The 400ml Budget
By Sonal Sahani · ISIPCA Versailles 9 min read Updated August 2026
Four hundred millilitres is not a length of time. It is a quantity, and it becomes a length of time only once you decide how many hours a day the machine will run. The useful conversion is into running hours, because that is the unit your timer actually spends. This page does that arithmetic properly, at six daily schedules, under both defensible readings of the specification — and it treats the 400ml as what it currently is for a SOSA Vaayu owner: the entire fragrance budget. SOSA does not currently sell a separate Vaayu refill oil. The four 100ml cold-air bottles in the box are the whole supply available today, so if long-term supply matters to you, confirm current refill availability with SOSA before spending ₹11,999.
Quick answers — read this first
Convert to hours first: at the rate implied by 400ml over 90 days of continuous running, 400ml is roughly 2,160 running hours. Read the same 90 days as an eight-hour day and it is roughly 720 running hours. The true figure is somewhere in that band.

Then divide by your schedule: at 8 hours a day that band is about 90 to 270 days. At 4 hours a day it is about 180 to 540 days. At 24 hours a day it is about 30 to 90 days.

Budget on the shorter column. It is always the conservative one, and planning short is the right instinct for a supply you cannot currently top up.

The supply position: no separate Vaayu refill oil is sold at present. 400ml is one tankful and, today, your whole budget. Ask SOSA before you buy.
The short answer
Short answer: 400ml in a SOSA Vaayu is specified to give 90+ days per fill at a mid intensity setting. Converted into running hours it is somewhere between about 720 and about 2,160 hours, depending on whether that 90-day figure assumes continuous operation or a typical intermittent day — the specification does not say which. Divide your side of that band by however many hours a day you intend to run, and you have your honest planning range.
Why hours rather than days: the machine consumes only while it is running. Auto-stop and the 1h / 4h / 8h / 24h timers mean a household that runs four hours an evening spends its 400ml at a sixth the daily rate of one that runs round the clock. Days are a consequence of hours; hours are the thing you actually control.
Shop: Vaayu ₹11,999 — 400ml, up to 1000m³, adjustable intensity, four timers, auto-stop, key-lock, under 38 dB, 5W. If you would rather have fragrance you can buy again at a published price, Sukoon ₹1,899 or a reed diffuser duo from ₹1,548. Free shipping above ₹499.
Straight answer
How long can 400ml of fragrance last in a scent machine?
1. Turn the volume into hours before you do anything else. The Vaayu's specification is 400ml and 90+ days per fill at mid intensity. If that assumes continuous running, the implied rate is 400 ÷ (90 × 24) = 0.185 ml an hour, and 400ml is about 2,160 running hours. If it assumes an eight-hour day, the rate is 400 ÷ (90 × 8) = 0.555 ml an hour, and 400ml is about 720 running hours.

2. The specification does not say which reading is intended, and I am not going to pick one on your behalf. The two differ by a factor of three, which is too large to paper over. Ask SOSA if your planning depends on it.

3. Divide by your daily schedule. 2,160 hours at eight hours a day is 270 days; 720 hours at eight hours a day is 90 days. So an eight-hour household is looking at somewhere between about three months and about nine.

4. Budget on the shorter figure. The 720-hour reading is always the conservative one, and for a supply you cannot currently replace, planning short is simply prudent. If you beat it, that is a good surprise rather than a broken plan.

5. Halving your hours roughly doubles your days. This is the most powerful thing you can do with the machine and it costs nothing. Four hours a day covering the evening you are actually in the room, rather than twenty-four, is the difference between a quarter and most of a year on the same box.

6. The 400ml is currently the whole budget. SOSA does not sell a separate Vaayu refill oil at present. The box holds four 100ml cold-air bottles — exactly one tankful — and that is the fragrance available today. Please ask SOSA where refill availability stands before you buy.

7. Do not plan on a substitute. The water-based Hotel Collection at ₹299 / ₹999 / ₹1,799 is built for ultrasonic machines, shares scent names with the cold-air oils, and must not go in a Vaayu. Reed diffuser oil goes in neither.

Made in India, CE / RoHS / SGS certified, and a portion of every order supports girl-child education through Nanhi Kali.
TL;DR: 400ml is roughly 720 to 2,160 running hours, depending which reading of the 90-day specification is right. Divide by your daily hours: about 30–90 days at 24 hrs a day, 90–270 days at 8 hrs, 180–540 days at 4 hrs. Budget on the shorter end, and ask SOSA about refill availability first — no separate Vaayu refill oil is sold today.
SOSA Vaayu waterless cold-air scent diffuser supplied with 400ml of fragrance
Four hundred millilitres, four timers
SOSA Vaayu · waterless cold-air nebuliser ₹11,999
Ships with four SOSA Hotel Collection cold-air fragrances at 100ml each — 400ml in total, in one of three combos chosen at checkout at the same price. The 400ml refillable tank is rated at 90+ days per fill at a mid intensity setting, and the 1h / 4h / 8h / 24h timers plus auto-stop are what decide how many days that becomes. Pressurised air atomises undiluted oil into a dry nano-mist across up to 1000m³ — no water, no heat, no residue. Bluetooth app and onboard buttons, adjustable intensity, key-lock, under 38 dB, DC 12V / 1A at 5W, 0.9 kg. No separate refill oil is currently sold; please ask SOSA before you commit.

Part one — converting a volume into running hours

Every consumption question in this category becomes tractable the moment you stop thinking in days and start thinking in hours. A tank does not empty because time passes; it empties because the pump runs. A machine switched off for a fortnight uses nothing. So the honest sequence is: work out the rate per running hour, multiply up to get the total hours in the tank, then divide by the hours you personally intend to run. Three steps, all of them plain division, and the only difficulty is that the specification gives us two possible starting rates rather than one.

1
STEP ONE · THE RATE
Two defensible readings, three times apart
The published pair is 400ml and 90+ days at mid intensity. To get a rate per hour you need the daily hours behind that, and the specification does not state them. Reading A — continuous operation: 90 days × 24 hours = 2,160 hours, so 400 ÷ 2,160 = 0.185 ml an hour. Reading B — an eight-hour day: 90 × 8 = 720 hours, so 400 ÷ 720 = 0.555 ml an hour. Both are reasonable interpretations of the same sentence, and they differ threefold. I have seen this ambiguity in the specification sheets of most machines in this category and it is rarely acknowledged; I would rather show you both columns than pretend to a precision nobody has published.
The takeaway: 400ml is either about 720 or about 2,160 running hours. Everything else follows from that one choice.
2
STEP TWO · YOUR SCHEDULE
Hours a day is the number you actually control
SOSA Vaayu cold-air nebulising diffuser with timersVaayu₹11,999 · 1h / 4h / 8h / 24hThe timers are not a convenience feature, they are the consumption control. A household running four hours an evening spends its supply at one-sixth the daily rate of one running twenty-four. And in most Indian homes the perceived difference is far smaller than six to one, because a cold-air field established over a few hours persists for hours after the machine stops — particularly in an air-conditioned space with the doors mostly shut. The honest default I would set for a home is eight hours covering the period you are actually in the room; the honest default for a let property is a shorter window timed around arrival and evening. Both are set from the app or the onboard buttons, and the key-lock stops anyone undoing them.
The arithmetic that matters most: halve the hours and you roughly double the days. Nothing else on the machine is that powerful.
3
STEP THREE · THE CONSTRAINT
Why 400ml is a budget rather than a first instalment
For most appliances, the quantity in the box is a sample and the real supply is a repeat purchase. That is not the position here, and I would rather you read it on this page than work it out later. SOSA does not currently sell a separate refill oil for the Vaayu. The four 100ml bottles that arrive with the machine are 400ml — exactly one tankful — and that is the cold-air fragrance available at the time of writing. There is no refill price for me to quote and I will not invent one. Nor is the water-based Hotel Collection a substitute: it is formulated for ultrasonic machines, it shares scent names because the compositions are the same, and it does not belong in a nebuliser. Ask SOSA where refill availability stands on the day you order, and treat the answer as part of the buying decision rather than a detail to sort out later.

Part two — the arithmetic, at six daily schedules and both readings

Straight division, shown so you can check it. The left pair uses the continuous reading at 0.185 ml an hour; the right pair uses the intermittent reading at 0.555 ml an hour. The final column is what I would put in a budget.

400ml, divided by your schedule
Six run patterns, both readings of the specification
Hours a day Reading A · ml a day Reading A · tank lasts Reading B · ml a day Reading B · tank lasts What I would plan on
8 hours ★ 1.48 ml 270 days · about 9 months 4.44 ml 90 days · about 3 months Budget 3 months, hope for more
24 hours 4.44 ml 90 days · about 3 months 13.3 ml 30 days · about 1 month Budget 1 month. Rarely worth doing at home
16 hours 2.96 ml 135 days · about 4.5 months 8.9 ml 45 days · about 6 weeks Budget 6 weeks
12 hours 2.22 ml 180 days · about 6 months 6.7 ml 60 days · about 2 months Budget 2 months
4 hours 0.74 ml 540 days · about 18 months 2.22 ml 180 days · about 6 months Budget 6 months — the sweet spot for most homes
2 hours 0.37 ml About 1,080 days · roughly 3 years 1.11 ml 360 days · about a year Budget a year. Enough for arrival scenting only
The honest caveat: every number here is arithmetic on two manufacturer figures — a 400ml tank and 90+ days per fill at a mid intensity setting — under two different assumptions about the daily run hours that figure implies, because the specification does not state them. Nothing here is a measurement, and nothing here accounts for your intensity setting, which is the other large variable: run above the mid step and both columns shorten. Connected volume, ceiling height, ventilation and season all move the setting you end up choosing. The single reliable figure is the one you generate yourself — mark the tank, run your real schedule unchanged for a fortnight, and divide. Finally, the frame around the whole table: SOSA does not currently sell a separate Vaayu refill oil, so the 400ml is today's entire supply. Confirm availability with SOSA before you buy.
Shop this guide
If a fixed budget is not what you want
The SOSA principle
A tank does not empty because time passes. It empties because the pump runs.
Which is why the timer, not the tank size, is the number that decides how long 400ml lasts — and why halving your hours roughly doubles your months.

Part three — living with a budget you cannot currently top up

Everything above is ordinary arithmetic. What makes it consequential is the constraint, and I would rather spend a full section on it than leave it as a footnote. SOSA does not currently sell a separate cold-air refill oil for the Vaayu. The 400ml supplied in the box is the fragrance available at the time of writing. That is a real gap in the product and we name it the way we name the missing replacement reeds in our reed range — plainly, in the shopping guide, rather than in the small print. If you are the kind of buyer for whom a signature scent held across a property for years is the entire point, this gap is not a detail; it is the decision. Ask SOSA three things before you order: is a cold-air refill available today, is one planned, and what is the guidance for an owner who finishes the 400ml in the meantime. Expect a straight answer to all three, and if you do not get one that fits your horizon, buy something else.

There is an entirely reasonable version of this decision that ends with you buying the Vaayu anyway, and I want to describe it fairly. If your problem is a large connected volume that no passive format has ever solved — a villa ground floor, an open-plan floor with a stairwell, a 250 to 800 cubic metre space — then nothing else in our range does what this machine does, and 400ml run at four to eight hours a day is a long time by any of the readings above. Buying it as a considered piece of equipment with a known supply of fragrance in the box is legitimate. Buying it on the assumption that refills will be there when you need them is not, because today they are not. The difference between those two purchases is entirely a matter of what you were told beforehand, which is why this page exists.

And the version that ends with you not buying it. If your connected volume is under about 100 cubic metres — which covers a great many flats described as open-plan — a Sukoon at ₹1,899 covers 270–320 sq ft, runs 16–18 hours on low, comes with three 15ml fragrances, and takes a water-based Hotel Collection you can buy again at 15ml ₹299, 100ml ₹999 or 300ml ₹1,799. If your problem is several closed rooms rather than one open volume, a pair of reed diffusers from ₹1,548 uses no electricity and refills at ₹2,399 for 300ml of oil. Neither of those is a consolation prize; they are the right tools for those jobs. One last boundary, since it belongs on every page in this cluster: a scent machine adds fragrance and nothing else. It does not purify, filter or deodorise, and it has no effect on anybody's health, sleep or mood.

Buying it with a known supply in the box is a considered purchase. Buying it assuming refills will appear is not, and today they have not.
— Sonal Sahani, SOSA

Part four — five ways to spend 400ml, and one way not to

The box contains four separate 100ml bottles rather than one large container, which makes allocation a genuine decision. Here are the five patterns I would actually recommend, with what each buys and who it suits.

The 400ml allocation
Five patterns for four bottles
Approach How you use the four bottles What it buys you Who it suits
One signature, held ★ All four bottles of the same scent, back to back A property with one recognisable identity Hosts and villa owners who want consistency
Test, then commit One bottle to find your setting, three held sealed A real measured rate before you spend the rest Anyone buying without a comparable space to judge from
Seasonal rotation One bottle a quarter, changed with the weather Variety, at the cost of a fixed identity Owner-occupiers rather than let properties
Arrival scenting only Short 1h and 4h windows before people come Years rather than months from the same box Weekend lets and properties used intermittently
Reserve pair Two in use, two kept sealed and cool as a buffer Insurance against the supply question Anyone uneasy about the refill position — sensibly so
Give closed rooms their own source Machine on the open floor only Less load on the tank, more character per room Reed duos from ₹1,548 · 6–8 weeks each
The one to avoid: full intensity, round the clock, from day one Burns a fifth of your supply proving the machine works An impressive first fortnight and a short quarter Nobody. Set low and wait a week instead
Honest notes for buyers: the 400ml tank, the four 100ml bottles and the 90+ days per fill at mid intensity are manufacturer specifications; every rate, hour and day figure on this page is arithmetic on them under a stated assumption, not a measurement, and real duration varies with intensity setting, run hours, connected volume, ceiling height, ventilation and season. The specification does not state the daily run hours behind the 90-day figure, which is why two columns appear rather than one. 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 diffuser oil goes in neither. Shelf life of the sealed cold-air bottles, warranty, AMC, installation, 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.
SOSA Fresh and Grounded reed diffuser duo set
A supply you can replenish indefinitely
SOSA Fresh & Grounded duo · reed diffusers ₹1,548 / 2 × 50ml
Morning Freshness — Malabar lemon, peppermint, Nilgiri eucalyptus — with Mountain Breeze's Himalayan pine, sage and Indian cedar. The two meet on green eucalyptus, so two rooms read as one house rather than as a seam. Six fibre reeds per bottle on an alcohol-free, phthalate-free, heat-stable CCT base; 50ml runs six to eight weeks, 130ml at ₹2,548 for the pair runs 14–18 weeks. When they finish you buy more, or a 300ml oil-only refill at ₹2,399 that keeps a vessel going eight to eleven months. No electricity, no settings, and a fully priced supply chain behind it.
SS
ISIPCA
Versailles
A note from Sonal

The first time somebody asked me how long 400ml lasts, I gave them the ninety-day figure and felt I had answered the question. I had not. They ran their machine two hours an evening in a modest flat and were still on their first bottle a year later, which was a lovely outcome but bore no relation to what I had told them. Somebody else with a villa and a stairwell ran it hard and was at the bottom of the tank in ten weeks. Both of them had been given the same number, and it had been the right number for neither.

So now I answer in running hours and show the working, including the part of the working that is genuinely uncertain. I do not know whether the ninety-day figure was measured continuously or on a typical day, and I would rather show you two columns and tell you to budget on the shorter one than pick the flattering column and let you find out.

And the thing I say on every page in this cluster, because it is the thing that matters most. We ship 400ml with this machine and we do not currently sell a separate cold-air refill. Ask us where that stands on the day you buy. A reader who knows our supply position before spending ₹11,999 is far better served than one who is sold a fantasy. Everything we make is composed in Pune, and a part of every order funds a girl's classroom through Nanhi Kali.

Frequently asked questions

How long does 400ml last in a scent machine?
On the SOSA Vaayu's specification of 400ml and 90+ days per fill at mid intensity, 400ml works out at somewhere between about 720 and about 2,160 running hours depending on how you read the daily hours behind that figure. At eight hours a day that is roughly three to nine months; at four hours a day, roughly six to eighteen; at twenty-four hours a day, roughly one to three. Budget on the shorter end of each band.
Why give a range instead of one number?
Because the specification quotes days per fill without stating the daily run hours it assumes, and the two reasonable readings differ threefold. Publishing one of them as fact would be a guess dressed as arithmetic. Publishing both, and telling you to plan on the conservative one, is the honest version. If the distinction matters to a commercial plan, ask SOSA which reading is intended.
Does the machine use oil while it is switched off?
No. Cold-air nebulisation only atomises oil while the pump is running, which is why the timers and auto-stop are the real consumption control and why a machine idle for a fortnight costs you nothing. This is a genuine difference from a reed diffuser, which evaporates continuously whether you are in the room or not and cannot be paused.
Should I keep some of the four bottles sealed?
It is a sensible approach, particularly given that no separate refill oil is currently sold. Use one bottle to establish your real consumption rate over a fortnight, then decide how to allocate the rest with a figure that applies to your house. Keep the unopened bottles capped, upright, cool and out of direct sunlight, as you would any fine fragrance concentrate.
Can I buy more of the cold-air oil?
Not at the time of writing — SOSA does not currently sell a separate Vaayu refill oil, and I am not going to quote a price for something that is not on sale. The 400ml in the box is the supply available today. The water-based Hotel Collection is a different product for ultrasonic machines and is not a substitute. Please confirm current refill availability with SOSA before you buy if this matters to you.
Large-space scenting · the 400ml budget
Roughly 720 to 2,160 running hoursyour timer decides the rest
The SOSA Vaayu at ₹11,999 ships with four Hotel Collection cold-air fragrances at 100ml each and runs a 400ml tank rated at 90+ days per fill at mid intensity, across up to 1000m³, with adjustable intensity, 1h / 4h / 8h / 24h timers, auto-stop and key-lock, under 38 dB on 5W. No separate Vaayu refill oil is sold at the time of writing, so 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 → Sukoon ₹1,899
Continue the read
More on consumption and running cost
Editorial standards & sources
About this guide: Written by Sonal Sahani, ISIPCA Versailles-trained founder and perfumer at SOSA Home & Body, on how long 400ml of fragrance lasts in a cold-air scent machine at different daily run schedules. The 400ml tank, the four 100ml bottles supplied and the 90+ days per fill at mid intensity are manufacturer specifications. Because the specification does not state the daily run hours behind the days-per-fill figure, two readings are shown — 0.185 ml per running hour (assuming continuous operation) and 0.555 ml per running hour (assuming an eight-hour day) — and every day and hour figure on this page is arithmetic on one of those two assumptions rather than a measurement. Real duration also varies with intensity setting, connected volume, ceiling height, ventilation and season. 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.
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