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Home appliances
In Delhi-NCR winters an under-sized purifier is a placebo. The one number that decides effectiveness is against your room's area — everything else is packaging.
Quick answer
at least 2x your room area (m²) in m³/hr.
True H13 filter.
Activated carbon in grams for odour/VOCs.
Check replacement filter cost.
In the shop
Read these off your phone at the counter. The answer tells you more than the price tag.
1.“What is the CADR, and what room size is that rated for?”
A good answer: A CADR number matched to your room's square feet, with air changes per hour.
2.“What does a full filter set cost per year?”
A good answer: A rupee figure. Filters often cost more than the purifier over three years.
A few questions about your situation, not about the product.
Add one short need not covered above.
Answer all 3 questions to see the spec sheet to shop with.
The sticker price is one part of owning an air purifier. Adjust the numbers to your own usage and tariff to see the electricity cost a star rating actually translates to.
Units per year
81 kWh
Cost per year
₹648 (≈$7.78)
Cost over 5 years
₹3,240 (≈$39)
Often more than the price difference between two models.
Running cost is low; filter replacements are the real recurring expense. Estimates only — actual consumption varies with ambient temperature, settings and unit condition. USD values are approximate.
An air purifier with a clogged filter is just a noisy fan. Budget for these from day one.
True HEPA filters trap particles; they must be replaced, not washed.
Removes odours and VOCs that HEPA alone cannot handle.
These are common add-ons for this category, not recommendations. Prices and availability vary; confirm fit and compatibility on the product page before buying.
Every new appliance already carries a brand warranty. An extended plan or AMC only adds value where it covers the parts that actually fail, with on-site service in your city — so read the cover, not the discount.
Ask these five questions
Usually not covered
Rule of thumb: a plan is rarely worth it if it costs more than ~15% of the product price, if the item is cheap to repair locally, or if the brand's own service network in your city is already strong.
These are comparison links, not recommendations — we don't sell plans and we don't rank providers. Some outbound links on KnowBeforeBuy are affiliate links. Cover, exclusions and pricing change; read the plan document before you pay.
Buy it locally
Sometimes the local dealer beats online on price, installation or the exchange offer. Tell us where you are and we'll list nearby stores. We don't rank or take money from any shop; results come from Google Maps.
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Clean Air Delivery Rate — volume of filtered air produced per hour.
Why it matters
Room area (sq ft) x 1.6 ≈ needed for ~5 air changes per hour.
What to check
Some brands quote 'coverage area' at only 2 air changes — too slow for polluted cities.
Captures 99.95% of 0.3 micron particles.
Why it matters
This is what removes PM2.5. '-type' or 'HEPA-like' does not qualify.
What to check
Look for the H13 or H14 grade printed on the filter itself.
Carbon that adsorbs smoke, VOCs and odours.
Why it matters
A thin carbon mesh does almost nothing; usable units carry several hundred grams of granular carbon.
What to check
Ask for carbon weight in grams, not 'carbon layer'.
Replacement price and months of use.
Why it matters
In high-pollution cities filters last 6–8 months, not the claimed 12. This is the real running cost.
What to check
Get the replacement filter price before buying the machine.
level at the fan speed you'd run overnight.
Why it matters
Quoted noise is on sleep mode, which often delivers a fraction of the .
What to check
Ask for and at the same speed setting.
Extra charged-particle features.
Why it matters
Some ionisers produce ozone, which irritates lungs.
What to check
Prefer purifiers where the ioniser can be switched off.
Bedroom units around 200 to living-room units of 400+ CADR.