Should I Count Rooms or Square Feet When Working Out How Many I Need?

Should I Count Rooms or Square Feet When Working Out How Many I Need?

★ ★ Honest sizing · three units, three different questions50ml ₹749 · 130ml ₹1,249 · Duo ₹1,498 · Sukoon ₹1,899A portion funds girl-child education
★ Sizing and quantity · the counting method
Rooms for how many. Square feet for which size. Hours for what to skip.
Rooms and square feet answer two different questions. Rooms tell you how many bottles; square feet tell you which size each one should be.
The two units
Not one or the other
The third unit is the one nobody uses: hours of occupancy. It decides which spaces you buy for first and which you skip entirely.
The missing unit
Hours, not size
A 200 sq ft formal drawing room used an hour a week deserves less than a 40 sq ft bathroom entered a dozen times a day.
Why size fails
Small beats unused
A 750 sq ft 2BHK has about six enclosures. Three are worth buying for: ₹1,349 + ₹1,299 + ₹749 = ₹3,397.
The worked example
Six spaces, three bottles
A 1,200 sq ft 3BHK has about eight. Four are worth buying for, at ₹4,146 — barely more than a flat two-thirds its size.
Why area barely matters
Eight spaces, four bottles
Adding reeds to a bottle you already own is free. Adding a bottle is not. Try the free dial before the paid one.
Before any of this
Reeds before bottles
Rooms and square feet answer two different questions. Rooms tell you how many bottles; square feet tell you which size each one should be.
The two units
Not one or the other
The third unit is the one nobody uses: hours of occupancy. It decides which spaces you buy for first and which you skip entirely.
The missing unit
Hours, not size
A 200 sq ft formal drawing room used an hour a week deserves less than a 40 sq ft bathroom entered a dozen times a day.
Why size fails
Small beats unused
A 750 sq ft 2BHK has about six enclosures. Three are worth buying for: ₹1,349 + ₹1,299 + ₹749 = ₹3,397.
The worked example
Six spaces, three bottles
A 1,200 sq ft 3BHK has about eight. Four are worth buying for, at ₹4,146 — barely more than a flat two-thirds its size.
Why area barely matters
Eight spaces, four bottles
Adding reeds to a bottle you already own is free. Adding a bottle is not. Try the free dial before the paid one.
Before any of this
Reeds before bottles
SOSA reed diffusersReeds from ₹749 SOSA Day and Night reed diffuser duoDuo ₹1,498 SOSA Sukoon 500ml ultrasonic diffuserSukoon ₹1,899 SOSA reed diffuser refillsRefill ₹2,399 SOSA Hotel Collection fragrancesScents ₹299
★ See the reed diffusers from ₹749 Two rooms — the duo ₹1,498
✓ Honest coverage figures — six reeds, up to about 150 sq ft, not "a whole home" ✓ 50ml ₹749 for 6–8 weeks · 130ml ₹1,249 for 14–18 · every total on this page adds up ✓ Most homes need fewer units than they expect — we will say so
Founder Diaries · Sizing and quantity

Should I Count Rooms or Square Feet When Working Out How Many I Need?

By Sonal Sahani · ISIPCA Versailles 10 min read Updated August 2026
Both, and neither on its own. Room count answers "how many bottles"; floor area answers "which size each bottle should be". They are not competing methods, they are two different questions, and the reason people end up over-buying is that they use one number to answer both. There is also a third unit, which almost nobody applies and which decides more of your bill than either: the hours somebody actually spends in each space.
Quick answers — read this first
Step one — count enclosures: how many separate air spaces the home has. That sets the maximum number of bottles.

Step two — measure each one: under about 150 sq ft, one bottle; a 50ml for small or short-stay spaces, a 130ml where people sit for hours.

Step three — rank by hours of occupancy: buy from the top down and stop when the list runs out of rooms anyone stands still in. A 750 sq ft 2BHK: six enclosures, three bottles, ₹3,397.
The short answer
Short answer: Count rooms to get how many and use square feet to get which size. A reed diffuser on six reeds holds one closed, still room of up to about 150 sq ft, so each enclosure under that figure needs at most one bottle, and the floor area only tells you whether that bottle should be a 50ml or a 130ml.
The unit that matters more than either: Hours of occupancy. Rank your enclosures by how long somebody is genuinely in them each day, then buy down the list and stop. A master bedroom gets eight or nine hours, a living-dining three or four, a bathroom minutes but with a fresh nose each time, a formal drawing room perhaps an hour a week. Size does not appear in that ranking at all.
The two worked counts: A 750 sq ft 2BHK has about six enclosures and needs three bottles: ₹1,349 + ₹1,299 + ₹749 = ₹3,397. A 1,200 sq ft 3BHK has about eight and needs four: ₹1,249 + ₹1,299 + ₹849 + ₹749 = ₹4,146. Sixty per cent more floor area, one more bottle.
In this guide
The unit
One reed diffuser · from ₹749
Two rooms
Day & Night duo · ₹1,498
Large rooms
Sukoon 500ml · ₹1,899
Straight answer
Should I count rooms or square feet?
1. Rooms for how many, square feet for which size. These answer different questions and neither substitutes for the other. The number of separate enclosures sets the ceiling on how many bottles could possibly be doing anything, because a bottle only ever serves the air space it is standing in. The floor area of each of those enclosures then tells you whether it takes a 50ml or a 130ml, and whether it takes one source or two. Using area alone gives you a total for the whole flat, which is a number that corresponds to nothing.

2. Then rank by hours, and cut the list there. Write your enclosures down and put a number of hours beside each: how long is anybody genuinely in there on an ordinary day? Master bedroom, eight or nine. Living-dining, three or four. Kitchen, two, but with cooking dominating. Second bedroom used as a study, one. Guest room, zero. Buy from the top of that list downward and stop when you reach the spaces with nothing in the column. Prioritise by hours of occupancy, not by room size — it is the single most reliable way to spend less and notice more.

3. Short-stay spaces are the exception that proves it. A bathroom might be occupied for a total of thirty minutes a day, and it still earns a bottle, because each of those visits begins with a nose that has not adapted to the space. What you are buying there is a series of arrivals rather than a stretch of dwelling. So the ranking is really by hours plus arrivals with a fresh nose — which is why a 40 sq ft bathroom beats a 200 sq ft drawing room used once a week, and why floor area gets the answer exactly backwards.

4. A worked count: a 750 sq ft 2BHK. Six enclosures — living-dining 220 sq ft, kitchen, master bedroom 130 sq ft, second bedroom 100 sq ft, bathroom, utility. Ranked by hours: master bedroom first, living-dining second, bathroom third on arrivals, second bedroom fourth at about an hour, kitchen and utility nowhere. Buy three: a 130ml for the living-dining at ₹1,349, a 130ml for the master bedroom at ₹1,299, a 50ml for the bathroom at ₹749. ₹3,397 for a flat the area sum said needed five bottles.

5. And a 1,200 sq ft 3BHK, to show how little area matters. Eight enclosures, four bottles: living-dining ₹1,249, master bedroom ₹1,299, the children's bedroom ₹849, the main bathroom ₹749 — ₹4,146. That is sixty per cent more floor area than the 750 sq ft flat and exactly one more bottle, because what grew was the size of the rooms and not the number of places anybody sits. If area were the right unit the second home would cost sixty per cent more. It costs twenty-two per cent more.

Made in India, composed by an ISIPCA Versailles-trained perfumer — and a portion of every order supports girl-child education through Nanhi Kali.
TL;DR: use both, for different questions. Room count sets how many bottles, because each bottle serves only the air space it stands in; floor area sets which size that bottle should be. Then rank the spaces by hours of occupancy and buy from the top down. A 750 sq ft 2BHK: six enclosures, three bottles, ₹3,397. A 1,200 sq ft 3BHK: eight enclosures, four bottles, ₹4,146.
SOSA reed diffusers, five scents
The unit you are counting
One SOSA reed diffuser From ₹749
The unit you are counting is one SOSA reed diffuser per occupied air space — 50ml from ₹749 for the small and short-stay ones, 130ml from ₹1,249 where people sit for hours. Six fibre reeds included; reed count is the volume dial and it is free to change. Composed and made in India, in Pune.
See the reed range →

What each unit is actually measuring

Floor area is the number people reach for because it is the number they know about their home, and it is genuinely useful — for one thing. The 150 sq ft coverage figure describes the size of one pocket of still air a single bottle can hold at equilibrium, in a closed room with a standard ceiling. That makes floor area the correct unit for a single question: is this particular enclosure inside or outside what one bottle handles? A 130 sq ft bedroom is inside it. A 220 sq ft living-dining is outside it and needs either two sources or a machine. What floor area cannot do is aggregate. Adding your rooms together and dividing by 150 treats the flat as one connected pocket, and a flat is a set of separate pockets with walls between them.

Room count fixes that but overshoots in the other direction, because it counts spaces regardless of whether anybody is in them. This is why "one per room" produces the eight-bottle 3BHK order that ends with four bottles quietly evaporating behind closed doors. The correction is the third unit. Occupancy hours are what you are really buying — a diffuser produces a slow, steady concentration in a space, and that concentration is only worth money if somebody is in the space to receive it. There is one adjustment: rooms entered briefly but repeatedly, like bathrooms, punch far above their hours, because your nose adapts to a constant smell within about twenty minutes and then stops reporting it. Time in a room is subject to that adaptation; arrivals into a room are not. So the working rule is hours of occupancy, with short repeat visits counted generously, and floor area used only to size the bottle you have already decided to buy.

The three steps, in order

1
STEP ONE · COUNT THE ENCLOSURES
This sets the maximum, not the answer
SOSA reed diffusersOne per spaceFrom ₹749Walk the flat and write down every space that can be shut off from the others. A 750 sq ft 2BHK typically gives six; a 1,200 sq ft 3BHK gives about eight. This is the ceiling on how many bottles could possibly be doing anything, because a passive source serves the air space it stands in and no other. It is not your shopping list — treating it as one is how people arrive at an eight-bottle order for a home where four rooms are empty all day.
Do not include: anything nobody occupies — a utility balcony, a storeroom, a passage.
2
STEP TWO · MEASURE EACH ONE
Area picks the size, not the number
Now put a floor area against each enclosure on your list. Under about 150 sq ft, one bottle covers it in closed, still conditions — and within that, use a 50ml at ₹749 for anything small or briefly used and a 130ml at ₹1,249 where people sit for hours, since the larger bottle works out at roughly ₹78 a week of use against ₹105 and halves how often you reorder. Over about 150 sq ft, or over about twenty-two feet end to end, one passive source will not reach the far side and you need two sources or a Sukoon at ₹1,899, which covers about 270–320 sq ft. This is the only step where square feet does any work at all.
Ceilings count too: 150 sq ft at nine feet is 1,350 cubic feet; at twelve it is 1,800. Coverage is a cubic quantity quoted in square feet.
3
STEP THREE · RANK BY HOURS
And stop when the hours run out
Put a number of daily hours beside each space and sort. Master bedroom eight or nine, living-dining three or four, kitchen two but dominated by cooking, second bedroom one, guest room zero, utility zero. Give bathrooms a promotion for arrivals — each visit begins with an unadapted nose, which is worth more than an hour of sitting in a room you have stopped smelling. Then buy from the top and stop wherever your budget or your patience does. The bottom of the list is not a gap in your home, it is money you kept.

Sizing by space — the same method across four home sizes

The method applied to real flats. Notice how little the totals move as the floor area grows, and that two of these rows come to ₹0 despite being perfectly good rooms.

The counting table
Enclosures, bottles and totals
Space What it needs How many Cost
750 sq ft 2BHK — six enclosures ★ Living-dining 130ml, master bedroom 130ml, bathroom 50ml. Second bedroom, kitchen and utility: nothing Three ₹3,397
600 sq ft 1BHK — four enclosures One 130ml for the living area, one 50ml for the bedroom. The bathroom is the third purchase, not the first Two ₹2,048
900 sq ft 2BHK with a second bathroom — seven enclosures Still three bottles. The guest bathroom is used a handful of times a month and does not earn one Three ₹3,397
1,200 sq ft 3BHK — eight enclosures Living-dining 130ml, master bedroom 130ml, children's bedroom 50ml, main bathroom 50ml Four ₹4,146
A 200 sq ft formal drawing room used about an hour a week Nothing. The largest room on this table and the one with the fewest hours in it None ₹0
A 40 sq ft bathroom entered a dozen times a day One 50ml on two or three reeds — small, enclosed, and met with a fresh nose every single time One from ₹749
A note on all of the above: the 750 sq ft total is ₹1,349 + ₹1,299 + ₹749 = ₹3,397 and the 1,200 sq ft total is ₹1,249 + ₹1,299 + ₹849 + ₹749 = ₹4,146. Sixty per cent more floor area, twenty-two per cent more money, one more bottle. All coverage figures assume closed rooms with still air and standard ceilings.
Shop this guide
Three units, and the one that decides your bill
SOSA reed diffusersOne room · the unitFrom ₹749Shop → SOSA reed diffuser duoTwo rooms · better value₹1,498Shop → SOSA Sukoon ultrasonic diffuserLarge room · a switch₹1,899Shop →
The SOSA principle
Square feet tells you which bottle. Rooms tell you how many. Hours tells you which ones to skip — and that is where the money is.
A 200 sq ft drawing room used an hour a week loses to a 40 sq ft bathroom entered twelve times a day. No area-based method can produce that answer.

Applying it to your own flat

Do it on paper, in ten minutes, before you open a shopping page. Three columns: the space, its rough floor area, and the hours anybody is genuinely in it on a weekday. Be honest in the third column — this is the one place where wishful thinking costs real money, and "we sit there sometimes" usually means twice a month. Sort by the third column, and draw a line under the last space with meaningful hours. Everything above the line is your shopping list; everything below it is money you have just saved. In most Indian flats the line falls after three or four rooms regardless of whether the home is 750 sq ft or 1,200.

Then set the reeds per space, because that is the free half of the decision. Reed count is the only volume control a reed diffuser has, and it works both ways at once: more reeds means more presence and a shorter bottle. Six reeds suits a living-dining or an entrance, where people arrive with fresh noses. Four suits a bedroom occupied for eight hours. Two or three suits a small bathroom, where six would be overwhelming. Setting each bottle to its space also staggers your reorders, since the four-reed bedroom bottle will outlast the six-reed living room one by several weeks. And if a space reads quiet, add a reed before you consider adding a bottle — the free dial first, every time.

Then buy in the order of your list, not all at once. The top two spaces on almost every list are the master bedroom and the living-dining, and two 130ml bottles there — ₹1,299 + ₹1,249 = ₹2,548 — is a complete, coherent home fragrance setup for a flat of any size up to about 1,200 sq ft. Live with it for a month before adding the bathroom bottle and, if you want it, the second bedroom. When the 130ml runs out, a 300ml refill at ₹2,399 fills it roughly twice, and refilling is the moment to fit fresh reeds, since clogged fibre is the commonest reason throw drops off after a few months. For scent, Evening Calm in bedrooms and Morning Freshness in the public rooms is the arrangement that survives most floor plans.

Floor area measures the flat. What you are buying is the number of hours somebody is actually standing in it.
— Sonal Sahani, SOSA

What to buy

Once you have your ranked list, this is what each line on it costs and what each format is genuinely for.

The counting edit
What to buy, in list order
Buy What it covers Lasts Price
One 50ml A single reed diffuser — the small and short-stay spaces at the bottom of your list — a bathroom, a study used an hour a day 6–8 weeks from ₹749
One 130ml ★ The value size — the top two lines of almost every list — the master bedroom and the living-dining 14–18 weeks from ₹1,249
The duo Day & Night duo — the top two lines solved in one purchase, with two blends composed to sit beside each other 6–8 weeks each ₹1,498
Sukoon 500ml ultrasonic — any single enclosure over about 150 sq ft, where one passive source cannot reach the far side Runs when you switch it on ₹1,899
300ml refill The running cost — the point where a three or four bottle home stops being a purchase and becomes a running cost Roughly 2 × 130ml fills ₹2,399
Honest notes before you buy: every figure on this page is the real one and every total adds up — check them. Two things are worth saying plainly before you buy anything. First, coverage claims are steady-state figures: a reed diffuser on six reeds holds a room of up to about 150 sq ft when that room is closed and still. Open a balcony door, run a fan, or raise the ceiling to twelve feet and the same bottle covers noticeably less — not because it is weak, but because coverage is measured in a condition your home may not be in. Second, most homes need fewer units than they buy. A room nobody sits in does not need fragrance; a corridor is a transit space, not a room; and adding reeds to an existing bottle is free, while adding a bottle is not. Reed count is the volume dial — six for full strength, four for a bedroom, two or three for a small bathroom — and it is the first thing to try. SOSA reed diffusers are oil-based and composed and made in India, in Pune; the Sukoon (₹1,899) runs the water-based Hotel Collection (from ₹299) and the two liquids are not interchangeable. Both are phthalate-free and composed to IFRA standards for home diffusion, not for skin or ingestion. A portion of every order supports girl-child education through Nanhi Kali.
SOSA Day and Night reed diffuser duo
Two rooms, one purchase
Day & Night Duo ₹1,498
Two 50ml bottles — Morning Freshness and Evening Calm — at ₹1,498 against ₹1,548 bought separately. The saving is small; the real reason to buy it is that it solves two rooms at once with scents chosen to sit beside each other rather than argue.
See the duo →
SS
ISIPCA
Versailles
A note from Sonal

People send me their floor plan and their square footage, and I always ask for something they have not measured: how many hours a day is anyone in each of these rooms? That column is the shopping list. The square footage only ever told us which bottle to put where.

The room that exposes this best is the formal drawing room. It is often the biggest space in the flat, it is the one people are proudest of, and it is used for an hour a week. By area it deserves two bottles. By hours it deserves nothing, and the honest advice is to scent it the day before people come and leave it alone the rest of the time. Meanwhile the bathroom that is forty square feet is entered twelve times a day by somebody whose nose has just walked in from somewhere else.

So: count the enclosures, measure them, then rank them by hours and draw a line. Most homes stop at three or four. If you buy the top two lines — ₹2,548 — and never buy anything else, you will have a home that reads as scented, and about ₹4,000 you did not spend. A portion of every order funds a girl's classroom through Nanhi Kali.

Frequently asked questions

Should I count rooms or square feet to work out how many diffusers I need?
Both, for different questions. Room count sets how many bottles, because each one serves only the air space it stands in. Floor area sets which size — under about 150 sq ft one bottle covers a closed, still room, and the area tells you whether a 50ml or a 130ml suits it. Dividing your total flat area by 150 gives a number that corresponds to nothing, because a flat is not one connected pocket of air.
What is the fastest way to work out how many I need?
List every space that can be closed off, put the daily hours anybody spends in each beside it, sort by hours and draw a line under the last one with real hours in it. Promote bathrooms slightly, because each visit starts with a nose that has not adapted. In most Indian flats the line falls after three or four spaces, whatever the floor area.
Does a bigger flat always need more diffusers?
Not proportionally, and often not at all. A 750 sq ft 2BHK needs three bottles at ₹3,397 and a 1,200 sq ft 3BHK needs four at ₹4,146 — sixty per cent more area for twenty-two per cent more money. What grows with area is the size of individual rooms, which changes which bottle goes where, not how many places anyone sits.
Should I buy a diffuser for the largest room first?
Only if it is also one of the most used. Size decides the format, not the priority. A 220 sq ft living-dining that the family sits in every evening deserves the first or second bottle; a 200 sq ft formal drawing room used for an hour a week deserves none. If the large room is over about 150 sq ft, remember it needs two sources or a machine rather than one bigger bottle.
How many separate spaces does a typical Indian flat actually have?
A 600 sq ft 1BHK has about four, a 750 sq ft 2BHK about six, a 900 sq ft 2BHK with two bathrooms about seven, and a 1,200 sq ft 3BHK about eight. Those are enclosure counts, not shopping lists — after ranking by hours the purchases come out at two, three, three and four respectively.
The method, in one line
Rooms for how many, square feet for which size, hours for what to skip
SOSA reed diffusers are 50ml from ₹749 for 6–8 weeks and 130ml from ₹1,249 for 14–18, composed and made in Pune, phthalate-free, six fibre reeds included, refillable at ₹2,399 for 300ml. The top two lines of most lists come to ₹2,548 and that is a complete setup. A portion of every order supports girl-child education through Nanhi Kali.
Shop SOSA reed diffusers → See the Sukoon ₹1,899
Continue the read
More on counting a whole home
Editorial standards & sources
About this guide: Written by Sonal Sahani, ISIPCA Versailles-trained founder and perfumer at SOSA Home & Body, on sizing home fragrance to a home. Coverage and longevity figures are SOSA's own for the stated products, measured on six reeds in a closed room of standard ceiling height; real rooms with draughts, heat or high ceilings will differ. Prices are current at the time of writing.

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.
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