Polycarbonate sheets have become a top choice for greenhouse construction worldwide due to their strength, UV protection, and thermal insulation. However, one of the most common questions we receive is: How thick should the polycarbonate sheets be for my greenhouse? The answer depends on several factors — your climate, structural requirements, crop type, and energy goals.
In this blog, we break down the most common polycarbonate thickness options and help you choose the right one for your needs.
Polycarbonate thickness affects three critical aspects of greenhouse performance:
Insulation performance (thermal efficiency and energy savings)
Structural strength (resistance to wind, snow, and impacts)
Light transmission (essential for plant photosynthesis)
Choosing the wrong thickness can lead to heat loss in winter, overheating in summer, or even structural failure in harsh weather.
Let’s explore the most popular polycarbonate sheet thicknesses used in greenhouses:
Best for: Small DIY greenhouses or areas with mild climates.
Light Transmission: ~85%
Thermal Insulation (U-value): ~3.9 W/m²K
Advantages:
Lightweight and affordable
Easy to cut and install
Limitations:
Low insulation value
Less impact resistance
Ideal if: You’re building a hobby greenhouse in a warm region.
Best for: Medium-sized greenhouses in temperate climates.
Light Transmission: ~82%
Thermal Insulation (U-value): ~3.3 W/m²K
Advantages:
Better thermal performance than 4mm
Good strength-to-weight ratio
Limitations:
Not suitable for extreme weather or heavy snow loads
Ideal if: You grow vegetables or ornamentals and want moderate energy savings.
Best for: Commercial greenhouses and high-value crops.
Light Transmission: ~80%
Thermal Insulation (U-value): ~3.0 W/m²K
Advantages:
Excellent insulation properties
Stronger structure, better impact resistance
Limitations:
Slightly higher cost
Heavier, may require stronger framing
Ideal if: You operate in colder climates or want better year-round growing performance.
Best for: Harsh climates, snow-prone areas, or energy-efficient greenhouses.
Light Transmission: ~77%
Thermal Insulation (U-value): ~2.7 W/m²K
Advantages:
Maximum insulation and durability
Excellent for energy-efficient greenhouses
Limitations:
Heaviest and most expensive
May reduce light levels for certain crops
Ideal if: You need to protect sensitive crops or lower heating costs in cold regions.
| Thickness | Light Transmission | Insulation (U-Value) | Suitable For |
|---|---|---|---|
| 4mm | ~85% | ~3.9 W/m²K | Hobby greenhouses in mild climates |
| 6mm | ~82% | ~3.3 W/m²K | Moderate climates, mid-sized greenhouses |
| 8mm | ~80% | ~3.0 W/m²K | Commercial farms, colder regions |
| 10mm | ~77% | ~2.7 W/m²K | Snowy, cold climates, energy-saving goals |
Ask yourself the following:
What’s your local climate?
Colder climates require thicker sheets (8mm or 10mm). Warmer climates can use 4mm or 6mm.
What crops are you growing?
High-value crops or heat-sensitive plants benefit from better insulation.
What’s your budget?
Thicker sheets offer better performance but cost more upfront.
What size is your greenhouse?
Larger structures benefit from thicker panels that offer more stability.
Most greenhouse-grade polycarbonate is twin-wall or multiwall, meaning it contains air pockets that enhance insulation. For example:
6mm twin-wall polycarbonate provides better performance than 6mm solid sheets.
10mm triple-wall polycarbonate is even more energy-efficient.
Multiwall sheets strike a great balance between strength, insulation, and light diffusion.
At our greenhouse factory, we typically recommend:
4mm–6mm twin-wall polycarbonate for small farms or mild climates
8mm–10mm twin or triple-wall polycarbonate for commercial growers, cold zones, or energy-conscious operations
And remember: Installation also matters. Ensure your greenhouse frame can support the weight of thicker sheets and is sealed properly to maximize insulation.
The thickness of polycarbonate sheets plays a vital role in greenhouse performance. While thinner sheets are economical, thicker options provide long-term savings through better insulation and durability.
Whether you are a backyard grower or managing a commercial greenhouse operation, selecting the right polycarbonate thickness ensures plant health, energy efficiency, and structural longevity.
As a professional agricultural greenhouse manufacturer, we offer complete greenhouse systems with high-quality polycarbonate sheet options tailored to your region and crops.
Contact us today for a free consultation and quote on your greenhouse project.
+86 189 2488 9901 +86 189 2455 5194
+86 189 2488 9901 +86 189 2455 5194
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