Premium PO films achieve ≥93% light transmittance, outperforming conventional films by 20%. Key checks:
✅ Verify third-party test reports
✅ Request transmittance decay curves (e.g., ≥85% after 3 years)
❌ Avoid films with <90% transmittance
Conduct 9-point measurements with a professional lux meter:
- Test during sunny midday
- 3m×3m spacing between points
- Acceptable variance: <15%
| Film Type |
Infrared Blocking |
Night Temp Control |
| Standard PO |
≤60% |
3-5℃ |
| Nano-Coated |
≥85% |
1-2℃ |
| Composite |
70-80% |
2-3℃ |
Ideal thickness (mm) = 0.08 + (Local Minimum Winter Temp / 10)
Example: -20℃ regions → 0.10mm thickness
- Grade A: Droplets slide off in <5 seconds
- Grade B: Droplets persist 5-15 seconds
- Grade C: High disease risk (droplets >15 seconds)
- Mist a 30cm×30cm sample
- Simulate greenhouse conditions with a heater
- <10 minutes to clear fog
- Must-have: HALS light stabilizers
- Avoid: Phthalate plasticizers (accelerate aging)
| Region |
Expected Lifespan |
| Coastal High-Salt |
1.5-2 years |
| Northern Dry |
3-4 years |
| Southern Humid |
2-3 years |
