CFM to Liters per Second Calculator
Convert air flow rates between CFM and L/s for air purifiers and HVAC systems
Air Flow Converter
Common Air Purifier CADR Values:
Formula: 350 CFM × 0.4719 = 0 L/s
Room Size Recommendations for 350 CFM
Optimal Coverage
543 sq ft
at 5 ACH
Maximum Coverage
816 sq ft
at 3.3 ACH
Recommended ACH
4.8
for air purifiers
Quick Reference Table
| CFM | L/s | m³/h | Typical Use |
|---|---|---|---|
| 100 | 47.19 | 170 | Small bedroom (150 sq ft) |
| 200 | 94.39 | 340 | Medium bedroom (300 sq ft) |
| 300 | 141.58 | 510 | Living room (450 sq ft) |
| 400 | 188.78 | 680 | Large room (600 sq ft) |
| 500 | 235.97 | 850 | Open plan (750 sq ft) |
Understanding CFM and L/s in Air Purification
What is CFM?
CFM (Cubic Feet per Minute) is the imperial unit for measuring air flow rate, commonly used in the United States for HVAC systems and air purifiers. In air purification, CFM is often referred to as CADR (Clean Air Delivery Rate), which indicates how much clean air an air purifier produces per minute.
Key Point: A higher CFM/CADR rating means the air purifier can clean larger rooms more effectively. The AHAM recommends choosing an air purifier with a CADR that's at least 2/3 of your room's square footage.
What is L/s?
L/s (Liters per Second) is the metric unit for air flow rate, widely used in Europe, Asia, and other regions following the metric system. Many international air purifier specifications list their performance in L/s or the related unit m³/h (cubic meters per hour).
Conversion Tip: To convert L/s to m³/h, multiply by 3.6. This is useful when comparing European air purifier models that often list specifications in m³/h.
Why This Conversion Matters for Air Purifiers
- International Shopping: Compare air purifier specifications across different markets and brands
- HVAC Integration: Match air purifier capacity with existing ventilation systems
- Professional Standards: Many commercial and medical-grade air purifiers use L/s in specifications
- Energy Calculations: European energy efficiency ratings often require L/s measurements
Air Purifier Sizing Guidelines
Room Size Calculation Formula:
- • Minimum CFM = Room Square Feet × 0.65 (for 2/3 rule)
- • Optimal CFM = Room Square Feet ÷ 1.55 (for 5 ACH)
- • Convert to L/s: CFM × 0.4719
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Frequently Asked Questions
How do I convert CFM to L/s?
To convert CFM to L/s, multiply the CFM value by 0.4719. For example, 300 CFM × 0.4719 = 141.58 L/s. This calculator performs the conversion automatically for you.
Is CFM the same as CADR?
CFM and CADR both measure air flow in cubic feet per minute, but CADR specifically refers to the volume of filtered air delivered by an air purifier. CADR is tested for three particle sizes: smoke, dust, and pollen.
What's the difference between L/s and m³/h?
Both are metric units for air flow. L/s (liters per second) and m³/h (cubic meters per hour) are related by: 1 L/s = 3.6 m³/h. European air purifiers often list their capacity in m³/h.
What CFM do I need for my room?
As a general rule, choose an air purifier with a CFM (CADR) that's at least 2/3 of your room's square footage. For a 300 sq ft room, you'd need at least 200 CFM. For optimal performance with 5 air changes per hour, divide your room's square footage by 1.55.
Why do European air purifiers use different units?
European and most international markets use the metric system, so air flow is measured in L/s or m³/h instead of CFM. This converter helps you compare specifications across different markets and make informed purchasing decisions.