JB AIR 400 Review: Owner's Verdict After Diwali Smog

Is the JB AIR 400 worth buying?

The JB AIR 400 is a sensibly priced HEPA 13 purifier for a bedroom or small room, but its 200 m³/h rating does not suit the 400 sq ft room printed on the box during heavy smog. I bought one with my own money, set it up at home, and kept it running through Diwali night, when the outdoor reading near my home peaked at 1,704.

Disclosure: The Tech Basket is not affiliated with JB Air in any way. We bought this purifier with our own money, and JB did not see or review this article. If a brand ever sends us a product or sample, we will say so clearly on that review, and the verdict stays our own. The share code further down can earn us a free filter if you use it. Read our review policy.

How well the JB AIR 400 cleans air

The AIR 400 pulls air through a pre-filter, an activated carbon layer and a HEPA 13 layer, then blows it out through the top vent. A laser particle sensor reads the room and drives Auto mode.

JB's headline claim is AQI 250+ down to 15 in 20 minutes. Going from 250 to 15 takes about 2.8 complete air changes, even in a perfectly sealed and mixed room. Doing that in 20 minutes needs 8.4 air changes an hour. At the AIR 400's rated 200 m³/h, that only works in a space of about 105 sq ft with an 8 ft ceiling.

That does not make the purifier weak. It means the claim fits a small room, and a real home leaks air through doors and windows, so expect slower results than the maths.

What Diwali night looked like outdoors

Diwali was far worse than any normal week. These readings come from a public outdoor monitor near my home.

At noon the next day the same monitor still showed PM2.5 at 157 µg/m³ and PM10 at 203 µg/m³. On a night like this, a purifier has to keep up with polluted air leaking in, so the room size you ask it to handle matters more than any brochure figure.

Smell and gases

The activated carbon layer is meant for odour. It is a thin layer inside a compact filter, so treat it as help with cooking smells and not as a cure for heavy smoke. JB's manual is clear about the limits: the purifier does not detect carbon monoxide or gas leaks, does not make oxygen and does not replace fresh-air ventilation.

What room size the AIR 400 really suits

The box says up to 400 sq ft. At an 8 ft ceiling that is about 90.6 m³, so 200 m³/h gives only 2.2 air changes an hour. A common sizing rule from the US appliance industry asks for a clean-air rate equal to two-thirds of the floor area, which is about 4.8 air changes an hour and points to roughly 175 sq ft for this model.

Air purifier room size calculator

Put in your own room below. The minutes assume a sealed, well-mixed room, so real rooms take longer.

I have three AIR 800 units on order and will cover them in a separate review once they arrive. If you are shopping for someone else, my Diwali gift gadgets guide covers cheaper options.

Living with it every day

The AIR 400 is a small, plain white column that fits on a desk or a floor corner. The display is the part I use most. It shows the current air reading and short messages such as "Breathe Easy" or "Feels like Oslo" when the air is clean. JB's manual says the sensor estimates indoor air quality and that its readings are not laboratory measurements, so treat the number as a guide.

Three touch controls sit on the unit. Power cycles through three fan speeds, Mode switches between Auto and Sleep, and Light switches between AQI Light, Night Light and Light Off. You can run it completely without the phone app, which matters given the app section below. On the back, two USB-C ports can charge a phone or power a small device.

My unit did have one build fault. The LED strip at the bottom of the front came loose and dropped, so I opened the purifier and taped it back in place. It looks like an early-batch build quality issue that JB should fix in later batches. If yours comes loose, ask JB support before you open it, because the unit is under warranty.

JB's published figures do not all agree. The box lists 42 W while the rating label lists 45 W. The box gives 20 to 48 dB, while another JB listing gives a 52 dB peak. The app's help section says the HEPA 13 layer captures 99.97% of particles as small as 0.1 microns, and JB has not published a test behind that figure.

The JB Air app is still in development

Setup takes four steps in the app, and the Wi-Fi step only accepts a 2.4 GHz network.

When it works, the app gives you fan speed with Auto and Sleep modes, light settings, a timer and daily routines. JB's founders have said sensor calibration is still being tuned, and owners on X have asked for Matter and Home Assistant support. If you want voice or automation control, read my piece on Google Home and AI agents for where smart homes are heading, and do not buy this purifier for that feature yet.

Is it the best air purifier under Rs 10,000?

The AIR 800 is the strongest value on paper, and the AIR 400 is a middle-of-the-table buy that wins on filter cost. This table ranks both JB units against the ten models on Amazon.in's HEPA air purifier Best Sellers list by price per unit of rated clean air.

Source: Amazon.in listings and its HEPA Best Sellers list, checked November 9, 2026, and JB's site for its own models. Amazon prices change often. Amazon does not list CADR for the Coway or the Levoit, so the Coway figure comes from Indian retailer listings and the Levoit figure from overseas listings, where it ranges from 58 to 78 by region.

• Price per clean air. The AIR 800 leads the list at Rs 25 per m³/h. The AIR 400 is at Rs 40, so the Xiaomi, Cuckoo, Qubo Q600 and Honeywell V1 and V2 all give more rated clean air for each rupee.
• Filters. JB wins this clearly. Rs 495 is about a quarter of the cheapest rival filter here.
• Three-year cost. At 12 hours a day, Rs 8 a unit and one filter a year, the AIR 400 costs about Rs 13,395 and the AIR 800 about Rs 18,413. The Xiaomi comes to about Rs 18,457, the Philips AC0950 about Rs 19,847 and the Cuckoo about Rs 24,225.
• Buying risk. JB's CADR figures are its own. The older brands sell through Amazon with its return handling, while JB is a very young company that sells only on its own site.

What it costs to own

The purchase price is only part of the cost. Filter swaps and electricity add up, especially if it runs all day through winter. JB says a filter lasts 12 to 24 months, and heavy smog will push it toward the short end.

Filter swaps, care and warranty

The swap needs no tools. Switch off and unplug the purifier, slide the old filter out through the top, wipe visible dust from the compartment with a dry cloth, slide the new filter in and switch on.

You then reset the filter counter with a 10-second hold, and JB's own instructions disagree on how. The manual's controls page says the Mode button, its filter steps show the Light button, and the app's help section names a Filter Reset button that my unit does not have. I have not swapped a filter yet, so ask JB support before you try it.

• Do not wash the main filters. JB says water damages the HEPA 13 and carbon layers. Only the pre-filter gets cleaned, with a dry cloth, a dry brush or a vacuum on low suction.
• Take the packing off a new filter. The warranty excludes damage from running the purifier with filter packing on.
• Do not ignore the alert for long. JB says to replace the filter within 15 to 30 days of the alert.
• Placement. Keep the inlet and outlet clear of curtains, furniture and bedding, and close doors and windows on bad-air days. JB also suggests running a ceiling fan to move air around. Its manual rules out bathrooms and kitchens with heavy oil fumes.

JB gives a 3-year limited warranty from the purchase or delivery date. It covers parts and labour for an eligible repair, and JB chooses whether to repair the purifier, replace a part or replace the unit. Keep your invoice and the serial number.

Filters are excluded unless they have a confirmed defect on arrival. The exclusions also cover falls, water entry, blocked vents, kitchen steam and oil, and unstable power or surges, which matters if your home has voltage swings.

Before you order

• Delivery. JB first promised shipping by July 31. A July 25 email blamed typhoons at the factory, moved the date to August 14 and offered refunds. Mine arrived on September 24. Other buyers on X reported delays too.
• Where to buy. It is sold on JB's own site, so you do not get the return handling that buyers expect from an Amazon or Flipkart sale.
• Returns. The policy covers faulty, damaged, incorrect or missing items, and it asks for an unboxing video. Record yours.
• Origin. JB says the product is designed and assembled in India, with Made in India starting in 2027. The label on my box lists China as the country of origin.
• Proof. JB promised lab results on June 12, and I could not find any published. Look for an independent CADR test or an AHAM Verifide seal before trusting any brand's figure.
• Early reviews. JB's memo says some influencers receive equity, and its 4.97 out of 5 survey included friends and investors.

JB Air share code and free filter offer

My own order also included an extra free filter from the launch offer, and JB's shipping emails listed it next to the purifier. Only the purifier reached me on September 24. JB's September 21 WhatsApp message had warned that the filter would ship separately by the end of October, and that shipping labels may show the whole order. The filter had not arrived as of November 9, 2026, past that date, and I will update this page when it does. If you order during an offer, check your box against the shipping email.

Final verdict

Buy the AIR 400 if you need clean air in a bedroom or home office and accept that a young brand is still finishing its app and its paperwork. Choose the AIR 800 for a bigger room. If you do order, copy the share code first so you get the free filter. More reviews are on the reviews page.

FAQs