Polycarbonate has become one of the most popular materials for greenhouse glazing due to its strength, thermal insulation, and light diffusion. But a common question from greenhouse builders and growers is:
“What is the best thickness of polycarbonate for my greenhouse?”
The answer isn’t one-size-fits-all. It depends on your climate, crop type, budget, and expected lifespan of the structure. In this guide, we’ll break down the performance of polycarbonate sheets by thickness—typically 4mm, 6mm, 8mm, and 10mm—so you can make an informed decision.
Polycarbonate panel thickness directly affects:
✅ Thermal insulation (R-value)
✅ Light transmission
✅ Durability against wind, hail, and snow
✅ Overall cost and weight
✅ Ease of installation and structural load
Understanding these factors will help you balance your needs for plant health, energy efficiency, and return on investment.
| Thickness | Light Transmission | R-Value (Insulation) | Durability | Best Use Case |
|---|---|---|---|---|
| 4mm | ~85% | 0.8 – 1.0 | Low | Warm climates, hobby |
| 6mm | ~80% | 1.3 – 1.6 | Moderate | Moderate climates |
| 8mm | ~75% | 1.6 – 2.0 | High | Commercial crops |
| 10mm | ~70% | 2.1 – 2.5 | Very High | Cold climates, snow load |
For light-loving crops (like tomatoes, cucumbers, orchids), you may prefer thinner sheets (4–6mm) that offer high light transmission.
For winter production or areas with cold nights, thicker panels (8–10mm) help retain warmth, reducing heating costs.
Consider using double-wall or twin-wall polycarbonate for both strength and insulation.
Best for:
Mild climates with little temperature variation
Seasonal greenhouses or low-cost hobby setups
Pros:
High light transmission (~85%)
Easy to cut and install
Affordable
Cons:
Low insulation—poor for cold seasons
Vulnerable to hail or heavy snow
Recommended for: Backyard growers in warm regions or spring/summer production.
Best for:
Growers who need moderate insulation without compromising light
Regions with mild winters
Pros:
Balanced light and thermal performance
Can be used year-round in temperate zones
More durable than 4mm
Cons:
Not ideal for harsh winters or heavy snow zones
Recommended for: Vegetable or flower growers in coastal or Mediterranean-like climates.
Best for:
Year-round growers in colder climates
Greenhouses requiring better heat retention
Pros:
Strong insulation (up to R-2.0)
Good structural strength
Reasonable light diffusion
Cons:
Slightly more expensive
Heavier and may need stronger framing
Recommended for: Commercial production of leafy greens, herbs, and flowers in northern zones.
Best for:
Harsh climates with snow, hail, and strong wind
Greenhouses requiring maximum energy efficiency
Pros:
Excellent insulation
High impact resistance
Long lifespan
Cons:
Heaviest and most expensive option
Lower light transmission (~70%)
Recommended for: Commercial greenhouses in alpine, continental, or snowy regions.
Twin-wall polycarbonate is standard for most greenhouses, offering insulation and light diffusion.
Multiwall polycarbonate (triple- or five-wall) offers better insulation but reduces light—great for nurseries or propagation zones.
Thicker sheets add more weight; ensure your frame (aluminum or galvanized steel) can support it.
Check for local snow load and wind speed ratings before installation.
Use proper profiles and sealing accessories to prevent water leakage or condensation.
| Region | Suggested Thickness |
|---|---|
| Southeast Asia | 4mm – 6mm |
| Southern Europe | 6mm – 8mm |
| Northern U.S./Canada | 8mm – 10mm |
| Middle East | 6mm – 8mm (UV grade) |
| Russia/Nordics | 10mm |
Ask yourself:
Do I need high light transmission or better insulation?
What is the coldest temperature in my area?
Is my greenhouse temporary or permanent?
Do I want lower upfront cost or long-term savings?
Most commercial growers choose 6mm or 8mm polycarbonate for the ideal trade-off between performance and cost.
As a professional greenhouse manufacturer, we supply customized polycarbonate greenhouses with panels ranging from 4mm to 10mm, tailored to your climate and crops.
Contact us today to get a quote or free consultation.
+86 189 2488 9901 +86 189 2455 5194
+86 189 2488 9901 +86 189 2455 5194
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