Cost analysis
The true cost of purification
The price on the box is roughly half of what a purifier costs you. Here is the five-year figure for real models in our catalogue — filters, membrane, electricity and, for RO, the water you pay for and never drink — with every assumption on the page.
Note
Purifiers are compared at the point of sale on one number, and it is the wrong one. Two units at ₹12,999 and ₹15,999 look like a ₹3,000 decision. If the cheaper one takes a ₹4,800-a-year cartridge and the dearer one takes a ₹2,900-a-year set, the cheaper unit costs ₹6,500 more by year five.
That is not an edge case. It is the ordinary structure of the category, and it is why consumable pricing is so consistently absent from the material shown to buyers. The margin on a purifier is thin and the margin on the consumables that only fit it is not.
The tables below apply the same five-year model to real models in our catalogue. Nothing here is a projection about a specific household — your tariff, your usage and your water are all different — but the shape holds regardless of the inputs, and the shape is the point.
Five-year cost, at a glance
| Model | Type | Purchase | Consumables/yr | 5-year total | Running share |
|---|---|---|---|---|---|
| AO Smith Z9 Green RO | Water | ₹33,990 | ₹4,500 | ₹59,280 | 43% |
| KENT Grand Plus | Water | ₹16,499 | ₹3,500 | ₹36,789 | 55% |
| LG PuriCare WW182EP | Water | ₹31,990 | ₹4,400 | ₹56,780 | 44% |
| Aquaguard Delight NXT | Water | ₹17,990 | ₹4,200 | ₹41,780 | 57% |
| AO Smith X7 | Water | ₹23,490 | ₹4,000 | ₹46,280 | 49% |
| Aquaguard Aura | Water | ₹25,490 | ₹5,200 | ₹54,280 | 53% |
| Philips 2000i Series AC2939 | Air | ₹24,990 | ₹3,500 | ₹48,620 | 49% |
| Coway Sleek Pro AP-1019C | Air | ₹26,990 | ₹4,000 | ₹53,120 | 49% |
| Dyson Purifier Cool Formaldehyde TP09 | Air | ₹54,900 | ₹6,500 | ₹93,530 | 41% |
| Xiaomi Smart Air Purifier 4 | Air | ₹12,999 | ₹2,200 | ₹30,129 | 57% |
| LG PuriCare 360° AS60GDWV0 | Air | ₹42,990 | ₹4,800 | ₹73,120 | 41% |
| Levoit Core 300S | Air | ₹9,999 | ₹2,400 | ₹28,129 | 64% |
Sorted by editorial score within each category. “Running share” is the proportion of the five-year total that is not the purchase price — the part of the decision that is invisible at the shop.
Water purifiers, line by line
| Cost line | 5-year total | Basis |
|---|---|---|
| Purchase price | ₹33,990 | Indicative street price, checked 2026-08-01 |
| Filters & service × 5 years | ₹22,500 | ₹4,500/year |
| Electricity × 5 years | ₹875 | 40 W × 1.5 h/day at ₹8/kWh |
| Water (including reject) × 5 years | ₹1,915 | 12 L/day product at 2.5:1 reject, ₹25/kL |
43% of the five-year cost is running cost, not the machine. The purchase price you compared at the shop was 57% of the decision.
| Cost line | 5-year total | Basis |
|---|---|---|
| Purchase price | ₹16,499 | Indicative street price, checked 2026-08-01 |
| Filters & service × 5 years | ₹17,500 | ₹3,500/year |
| Electricity × 5 years | ₹875 | 40 W × 1.5 h/day at ₹8/kWh |
| Water (including reject) × 5 years | ₹1,915 | 12 L/day product at 2.5:1 reject, ₹25/kL |
55% of the five-year cost is running cost, not the machine. The purchase price you compared at the shop was 45% of the decision.
| Cost line | 5-year total | Basis |
|---|---|---|
| Purchase price | ₹31,990 | Indicative street price, checked 2026-08-01 |
| Filters & service × 5 years | ₹22,000 | ₹4,400/year |
| Electricity × 5 years | ₹875 | 40 W × 1.5 h/day at ₹8/kWh |
| Water (including reject) × 5 years | ₹1,915 | 12 L/day product at 2.5:1 reject, ₹25/kL |
44% of the five-year cost is running cost, not the machine. The purchase price you compared at the shop was 56% of the decision.
| Cost line | 5-year total | Basis |
|---|---|---|
| Purchase price | ₹17,990 | Indicative street price, checked 2026-08-01 |
| Filters & service × 5 years | ₹21,000 | ₹4,200/year |
| Electricity × 5 years | ₹875 | 40 W × 1.5 h/day at ₹8/kWh |
| Water (including reject) × 5 years | ₹1,915 | 12 L/day product at 2.5:1 reject, ₹25/kL |
57% of the five-year cost is running cost, not the machine. The purchase price you compared at the shop was 43% of the decision.
| Cost line | 5-year total | Basis |
|---|---|---|
| Purchase price | ₹23,490 | Indicative street price, checked 2026-08-01 |
| Filters & service × 5 years | ₹20,000 | ₹4,000/year |
| Electricity × 5 years | ₹875 | 40 W × 1.5 h/day at ₹8/kWh |
| Water (including reject) × 5 years | ₹1,915 | 12 L/day product at 2.5:1 reject, ₹25/kL |
49% of the five-year cost is running cost, not the machine. The purchase price you compared at the shop was 51% of the decision.
| Cost line | 5-year total | Basis |
|---|---|---|
| Purchase price | ₹25,490 | Indicative street price, checked 2026-08-01 |
| Filters & service × 5 years | ₹26,000 | ₹5,200/year |
| Electricity × 5 years | ₹875 | 40 W × 1.5 h/day at ₹8/kWh |
| Water (including reject) × 5 years | ₹1,915 | 12 L/day product at 2.5:1 reject, ₹25/kL |
53% of the five-year cost is running cost, not the machine. The purchase price you compared at the shop was 47% of the decision.
Air purifiers, line by line
| Cost line | 5-year total | Basis |
|---|---|---|
| Purchase price | ₹24,990 | Indicative street price, checked 2026-08-01 |
| Filters & service × 5 years | ₹17,500 | ₹3,500/year |
| Electricity × 5 years | ₹6,130 | 35 W × 12 h/day at ₹8/kWh |
49% of the five-year cost is running cost, not the machine. The purchase price you compared at the shop was 51% of the decision.
| Cost line | 5-year total | Basis |
|---|---|---|
| Purchase price | ₹26,990 | Indicative street price, checked 2026-08-01 |
| Filters & service × 5 years | ₹20,000 | ₹4,000/year |
| Electricity × 5 years | ₹6,130 | 35 W × 12 h/day at ₹8/kWh |
49% of the five-year cost is running cost, not the machine. The purchase price you compared at the shop was 51% of the decision.
| Cost line | 5-year total | Basis |
|---|---|---|
| Purchase price | ₹54,900 | Indicative street price, checked 2026-08-01 |
| Filters & service × 5 years | ₹32,500 | ₹6,500/year |
| Electricity × 5 years | ₹6,130 | 35 W × 12 h/day at ₹8/kWh |
41% of the five-year cost is running cost, not the machine. The purchase price you compared at the shop was 59% of the decision.
| Cost line | 5-year total | Basis |
|---|---|---|
| Purchase price | ₹12,999 | Indicative street price, checked 2026-08-01 |
| Filters & service × 5 years | ₹11,000 | ₹2,200/year |
| Electricity × 5 years | ₹6,130 | 35 W × 12 h/day at ₹8/kWh |
57% of the five-year cost is running cost, not the machine. The purchase price you compared at the shop was 43% of the decision.
| Cost line | 5-year total | Basis |
|---|---|---|
| Purchase price | ₹42,990 | Indicative street price, checked 2026-08-01 |
| Filters & service × 5 years | ₹24,000 | ₹4,800/year |
| Electricity × 5 years | ₹6,130 | 35 W × 12 h/day at ₹8/kWh |
41% of the five-year cost is running cost, not the machine. The purchase price you compared at the shop was 59% of the decision.
| Cost line | 5-year total | Basis |
|---|---|---|
| Purchase price | ₹9,999 | Indicative street price, checked 2026-08-01 |
| Filters & service × 5 years | ₹12,000 | ₹2,400/year |
| Electricity × 5 years | ₹6,130 | 35 W × 12 h/day at ₹8/kWh |
64% of the five-year cost is running cost, not the machine. The purchase price you compared at the shop was 36% of the decision.
The water nobody counts
Reverse osmosis discards water by design. A domestic unit typically produces one litre of drinking water for every two to four litres sent to the drain, and the ratio worsens as feed TDS rises — so a household on a saline borewell wastes considerably more than one on clean municipal supply.
On metered municipal supply at ₹25 per kilolitre, that is a modest annual figure. On tanker-fed supply, where households routinely pay several hundred rupees per kilolitre, it stops being modest. And in a city with genuine water scarcity it is a cost that does not appear on any bill at all.
Two practical responses. First, do not fit RO where the feed water does not require it — below about 200 ppm you are discarding water to remove minerals that were not a problem. Second, if you do fit it, plumb the reject line to a storage tank for washing and flushing rather than to the drain. That is what “zero wastage” systems actually do, and you can do it to almost any unit for the cost of a length of pipe.
Methodology
- Purchase price is the indicative street price held for each product, with the date it was last checked shown alongside.
- Consumables use each product's own maintained annual running cost figure. Where the catalogue does not hold one, the segment band from our filter price index is used and the row is labelled as an estimate.
- Electricity for RO assumes 40 W for 1.5 hours a day; for air purifiers 35 W average for 12 hours a day. Both at ₹8 per kWh.
- Water cost for RO assumes 12 litres a day of product at a 2.5:1 reject ratio, charged at ₹25 per kilolitre. Households on unmetered supply pay this in tanker cost or not at all.
- Nothing is discounted for inflation or the time value of money. Both would raise the five-year figure rather than lower it, so the totals here are conservative.
- Breakdown repairs outside normal servicing are not modelled, because there is no honest basis for an average. A single membrane failure outside warranty adds ₹1,500 to ₹3,500.
Calculated from stated inputs. The formula is shown alongside the figure. Where a per-model consumables figure was not available, the segment band from our filter price index was used — currently ₹2,607–₹14,883 a year for water and ₹2,000–₹37,400 for air — and the affected row is labelled. Last reviewed 2026-08-08.