How Many Air Purifiers Do You Need In A Home? A Practical Guide For Delhi-NCR Residents

Air pollution in Delhi-NCR has reached alarming levels once again, with the Air Quality Index (AQI) consistently breaching the “severe” and “hazardous” categories. Today, on November 3, 2025, areas like Wazirpur, Rohini, and Dwarka recorded AQI levels above 400, placing them in the “hazardous” zone. Despite government interventions under the Graded Response Action Plan (GRAP), including construction bans and traffic curbs, indoor air remains dangerously polluted. For residents, especially those with respiratory conditions, children, and the elderly, air purifiers have become a necessity rather than a luxury. But one question persists: Is one air purifier enough for an entire home?

Delhi's AQI demands 24/7 air purification indoors.
Photo Credit: Unsplash

The short answer is no. In Delhi's current pollution scenario, a single air purifier cannot effectively clean the air across multiple rooms. This guide breaks down how many purifiers you actually need, why, and how to place them for maximum impact.

Also Read: Delhi AQI: How To Clean Your Air Purifier Filter To Avoid Seasonal Allergies

Why One Air Purifier Isn't Enough

Most air purifiers are designed to clean the air in a single enclosed space. Their effectiveness depends on several factors:

• Room size and layout
• Clean Air Delivery Rate (CADR)
• Air circulation and obstructions
• Pollution hotspots (e.g., kitchens, pet areas)

According to media reports, even high-end purifiers struggle to clean air beyond their rated coverage area. For example, a purifier with a CADR of 250 m³/h is suitable for rooms up to 300 sq ft. In a typical 3BHK apartment of 1500 sq ft, this means you'll need at least three to four purifiers to ensure comprehensive coverage.

Delhi's Air Quality: A Snapshot

As of early November 2025, Delhi's AQI has hovered between 350 and 421, with PM2.5 concentrations reaching 488 µg/m³ post-Diwali, the highest in five years. These levels are more than eight times the safe limit prescribed by the World Health Organization. Prolonged exposure to such air may reportedly cause:

• Respiratory illnesses
• Eye irritation
• Sleep disturbances
• Increased risk of heart disease and stroke

Indoor air is not immune. Pollutants seep in through windows, doors, and ventilation systems, making indoor purification essential.

Clean air starts with smart purifier placement.
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How Many Air Purifiers Do You Need? Room-by-Room Breakdown

Let's break it down based on a standard 3BHK layout:

1. Master Bedroom

• Recommended CADR: 350–450 m³/h
• Why: You spend 6–8 hours here daily. Clean air during sleep is crucial for respiratory health.
• Placement Tip: Keep it 3–6 feet from the bed, ideally at breathing height.

2. Secondary Bedroom / Study

• Recommended CADR: 300–400 m³/h
• Why: Often used for work or children's activities. Sensitive groups need cleaner air.
• Placement Tip: Avoid corners and walls; allow 1–2 feet clearance around the unit.

3. Living Room / Dining Area

• Recommended CADR: 600 m³/h or two units of 300 m³/h
• Why: Largest space, often open-plan. High foot traffic and pollutant exposure.
• Placement Tip: Central location, away from electronics and curtains.

4. Kitchen (Optional but useful)

• Recommended CADR: 250–300 m³/h with activated carbon filter
• Why: Cooking fumes and VOCs are common indoor pollutants.
• Placement Tip: Near the stove but away from direct heat sources.

Expert Advice On Placement And Efficiency

Proper placement is as important as quantity. It is recommend:

• Avoid corners and walls: These obstruct airflow.
• Central positioning: Allows better circulation.
• Near pollution sources: Like windows, doors, or cooking areas.
• Height matters: Ideally at breathing level, not on high shelves.

Also, consider running purifiers 24/7 during peak pollution days and changing filters regularly to maintain efficiency.

Invest in multiple purifiers for healthier living.
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Cost vs Coverage: Is It Worth It?

While buying multiple purifiers may seem expensive, the health benefits far outweigh the costs. A single hospital visit due to pollution-triggered asthma or bronchitis can cost more than a mid-range purifier. Moreover, using multiple smaller units is often more energy-efficient and quieter than one large unit.

Tailor Your Air Purifier Strategy

There's no one-size-fits-all answer. Your purifier needs depend on:

• Home size and layout
• Health conditions
• Pollution levels
• Budget

But as a rule of thumb for Delhi-NCR homes during peak pollution:

One air purifier per enclosed room is essential. For open spaces, consider two units or a high-CADR model. Investing in clean air is investing in your health. With Delhi's AQI regularly breaching safe limits, multiple air purifiers are not a luxury, they're a necessity.

Frequently Asked Questions (FAQs)

1. Can one air purifier clean the air in my entire home?

No, most air purifiers are designed for single-room use. For effective purification, you need one unit per enclosed space or a high-CADR model for larger areas.

2. How do I calculate how many air purifiers I need?

Use the room size and match it with the purifier's CADR rating. For example, a 300 sq ft room needs a purifier with at least 250–300 m³/h CADR.

3. Should I keep air purifiers on all day?

Yes, especially during high pollution days in Delhi-NCR. Continuous operation ensures consistent air quality and reduces pollutant buildup indoors.

4. Where should I place my air purifier for best results?

Place it centrally in the room, away from walls and corners, and ideally at breathing height. Avoid placing it near curtains or electronic devices.

5. Do I need an air purifier in the kitchen or bathroom?

While not essential, placing a purifier with a carbon filter in the kitchen can help reduce cooking fumes and VOCs. Bathrooms may need one if mould or humidity is a concern.