In today’s farming practices, using plastic covers for greenhouses is important for creating the best environment for plants to grow. When choosing a cover for a greenhouse, two popular types are double-layer polyethylene film and extruded polyethylene film. Knowing how these two types differ can help farmers and greenhouse managers pick the right one depending on the weather, the kind of crops they’re growing, and how much they’re willing to invest.
What is Double-Layer Polyethylene Film?
Greenhouse Double-layer plastic refers to a system where two layers of plastic cover are installed over the greenhouse structure, creating an air gap between them. This air space, usually maintained by a blower (fan) system, acts as an effective thermal insulator.
Advantages of Double-Layer Film:
High thermal insulation: up to 50% reduction in heat loss compared to single-layer film
Energy savings: significantly lower heating costs in cold seasons
Cost-effective: lower price compared to advanced materials
Easy to install on existing greenhouse structures
Disadvantages of Double-Layer Film:
Requires regular maintenance to prevent damage or punctures
Shorter lifespan (typically 3–5 years)
Not highly resistant to heavy snow loads or strong winds without a reinforced frame
What is Extruded Polyethylene Film?
Extruded polyethylene film is produced through special extrusion and molding processes, resulting in uniform thickness, density, and strength. These films are often used together with extruded aluminum frames. For more information, you can refer to the article: “How to Build a Greenhouse Resistant to Snow and Wind?”
Advantages of Extruded Film:
Very high strength against pressure, snow, hail, and strong winds
Longer lifespan: 10 years or more
High safety: ideal for commercial greenhouses and high-rainfall areas
Resistant to UV rays, decay, and chemicals
Disadvantages of Extruded Film:
Higher price compared to regular films
Requires a stronger structure for proper installation
Comparison: Extruded Polyethylene Film vs. Double-Layer Film
| Feature | Double-Layer Film | Extruded Film |
|---|---|---|
| Structure | Two layers with an air gap between them | Thicker single layer produced through extrusion |
| Thermal Insulation | Very high due to air gap between layers | Medium, relies on greater thickness |
| Resistance to Cold & Snow | Good, but durability of joints must be checked in heavy snow | Very high, suitable for snowy and windy regions |
| Lifespan | 3–5 years depending on quality and conditions | 5–8 years or more |
| Price | Lower cost | Higher cost due to production technology and materials |
| Installation | Relatively simple but requires proper anchoring | Requires higher precision, sometimes more specialized installation |
| Best For | Small, seasonal greenhouses or mild climates | Permanent greenhouses, cold or snowy regions |
Which Film is Right for You?
Choosing between double-layer and extruded polyethylene film depends on several factors:
If you are in a region with mild winters and low wind, and want an affordable solution for a home or small greenhouse, double-layer film is a suitable choice.
If you are in a cold, snowy, or windy area and want a permanent, safe, and durable greenhouse, extruded film is the superior option.
Applications of Double-Layer and Extruded Films in Iran
Considering Iran’s diverse climate:
Double-layer film is more commonly used in provinces with mild winters such as Fars, Isfahan, or Khuzestan.
Extruded film is popular in regions with heavy snowfall or strong winds such as Azerbaijan, Kurdistan, Ardabil, and Mazandaran.
Final Conclusion
By knowing the differences in how double-layer and extruded polyethylene films are made, how they work, and how much they cost, farmers can choose the best option for their area and their greenhouse plans. If the goal is to have a strong, safe, and long-lasting greenhouse, extruded films are a better choice, even though they might cost more at first. To buy different types of greenhouse plastic and films, check out the product page for more information.