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Air Purifier CADR Explained - Room Sizing, Filter Costs & Real-World Math
Understand CADR ratings for air purifiers, how to size them for your room, calculate filter replacement costs, and avoid underpowered models that do not clean effectively.
WWCD Tech Review Specialist
Senior Technology Analyst
Technical Guide
Technical explanation
🌬️ Air Purifier CADR Explained - Real-World Math
What You'll Learn
Master CADR ratings to choose the right air purifier size for your room, calculate hidden filter costs, and avoid underpowered models that waste money without cleaning effectively.
💡 Quick Summary
📏 CADR Rating
Higher CADR = more air cleaned per minute. Match CADR to your room volume for effective cleaning.
💰 Filter Costs
HEPA filters cost ₹2,000-6,000/year. Always check filter availability before buying.
⚡ Energy Use
30-70W consumption. Running 12 hours daily adds ₹200-400/month to electricity bills.
📊 1. CADR (Clean Air Delivery Rate) Explained
The Most Important Specification
CADR measures how much clean air an air purifier delivers per minute - it's the key metric for sizing your purchase
🔬 Understanding CADR Numbers
What CADR Measures
Real-World Translation
⚠️ Important: For Indian pollution levels, choose CADR 2-3x your room volume for effective cleaning. Lab conditions don't match real-world dust and pollutants.
📏 2. Room Sizing Calculator
Match CADR to Your Space
Proper sizing ensures effective air cleaning without overspending on unnecessarily powerful models
🏠 Room Size to CADR Chart
| Room Size | Minimum CADR | Recommended CADR | For Heavy Pollution |
|---|---|---|---|
| Up to 200 sq ft | 150 m³/h | 200 m³/h | 250 m³/h |
| 200-400 sq ft | 250 m³/h | 350 m³/h | 450 m³/h |
| 400+ sq ft | 400 m³/h | 500+ m³/h | 600+ m³/h |
✅ Right-Sized Benefits
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•
Effective Cleaning: Proper air circulation
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Energy Efficiency: Not overworking the motor
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•
Noise Control: Runs at optimal speed
❌ Undersized Problems
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Poor Performance: Can't keep up with pollution
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•
Constant Running: Higher electricity bills
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Filter Overload: Shorter filter life
💰 3. Filter Replacement Costs
The Hidden Ongoing Expense
Filter costs can exceed the air purifier price over 3-4 years - factor this into your budget
🔄 Filter Types & Replacement Schedule
Pre-Filter
HEPA Filter
Carbon Filter
📊 Annual Filter Cost Examples
Budget Air Purifier (₹15,000)
Premium Air Purifier (₹40,000)
⚠️ Critical: Always check filter availability and pricing before buying. Some brands discontinue models, leaving you with expensive paperweights.
⚡ 4. Energy Consumption & Running Costs
Electricity Usage Breakdown
Air purifiers consume 30-70W, similar to a ceiling fan - understand the monthly electricity impact
💡 Power Consumption Analysis
💡 5. Practical Buying Tips
Smart Shopping Strategy
Key considerations to avoid expensive mistakes and choose the right air purifier for your needs
✅ Before You Buy
- • Check CADR rating for your room size
- • Calculate filter costs for 3 years
- • Verify filter availability in India
- • Read warranty terms for motors and electronics
- • Check noise levels for bedroom use
❌ Avoid These Mistakes
- • Ozone-generating ionizer purifiers
- • Underpowered models for your room size
- • Unknown brands with no filter support
- • Washable HEPA claims (not genuine HEPA)
- • UV-only purifiers without proper filtration
❓ 6. Frequently Asked Questions
Common Doubts Clarified
Essential answers about CADR, filters, and air purifier effectiveness
Q: Is higher CADR always better?
A:
Yes for effectiveness, but too high wastes energy if your room is small. Match CADR to room size for optimal efficiency and noise levels.
Q: Can I wash HEPA filters?
A:
No, genuine HEPA filters are not washable. Only pre-filters can be washed. "Washable HEPA" claims are usually referring to basic foam filters.
Q: Do all purifiers remove gases and odors?
A:
No, only models with activated carbon filters remove gases and odors. HEPA-only purifiers don't eliminate cooking smells or chemical vapors.
Q: How often should I replace filters?
A:
HEPA filters: 6-12 months depending on pollution levels. Carbon filters: 3-6 months. Check your purifier's filter indicator or follow manufacturer guidelines.
Q: What's the total cost of ownership?
A:
For a ₹25,000 purifier: Device cost + ₹4,000-6,000 annual filters + ₹2,400-4,800 annual electricity = ₹45,000-60,000 over 3 years.
🎯 Key Takeaway
Choose CADR 2-3x your room volume for Indian pollution. Budget for ₹4,000-8,000 annual filter costs. Always verify filter availability before purchase.
🎯 Key Takeaways
This article explains the key concepts behind air purifier in simple terms for air purifier buyers.