Author: Corenthin Chassouant
Corenthin, an Agronomist (MSc, agr.) and Sales Manager, specializes in greenhouse and horticulture projects across North America. With a background in agricultural engineering and expertise in agronomy, horticulture, biomass valorization, and agro-ecology, Corenthin advises growers globally. Previous experience in Southeast Asia with a European company led to expertise in tropical greenhouse solutions and turnkey project management. Currently, Corenthin manages a team of sales representatives and distributors in Canada and the U.S., while actively handling key account customers. With international experience and technical knowledge, Corenthin supports growers in optimizing their operations and implementing sustainable horticultural solutions.
Maximizing Greenhouse Efficiency Strategies to Reduce Heat Loss
Heating costs can represent over 30% of a greenhouse's total operating expenses, particularly in colder climates. Minimizing heat loss is essential for maintaining profitability and optimizing energy use. This article explores key mechanisms of heat loss and effective strategies to enhance greenhouse insulation and efficiency.
Understanding Heat Loss Mechanisms
Greenhouses lose heat through four primary mechanisms:
- Conduction: Occurs when heat is transferred from the warm interior air to the cooler exterior through the greenhouse cover. The rate of loss depends on the temperature differential and the insulating properties of the covering material.
- Convection: Happens when warm air escapes through ventilation or unintentional leaks. Proper sealing and maintenance can significantly reduce these losses.
- Leakage: Infiltration losses account for up to 20% of total heat loss as cold air enters through cracks and gaps, displacing warm air.
- Radiation: During nighttime, heat stored in plants and the greenhouse structure is emitted as infrared radiation, which can escape if not properly blocked.
Choosing the Right Roofing Materials
Selecting appropriate greenhouse coverings is crucial in reducing heat loss. Below is a ranking of common materials from least to most insulating:
- Single-glazed glass
- Single-wall polyethylene
- Double-walled polycarbonate (8 mm thick)
- Double-glazed glass
- Double-wall inflated polyethylene
- Double-wall inflated polyethylene with a thermal inside layer
- Insulated sandwich panels (e.g., Kingspan-type, 3.5 inches thick)
The heat transfer coefficient (U-value) determines a material’s insulation capacity—lower values indicate better thermal efficiency. For example:
- Single glass: U ≈ 6.2 W/(m²-°C)
- Double-layer inflated thermal polyethylene: U ≈ 2.8 W/(m²-°C)
This represents an improvement of nearly 55% in insulation when using double-layer inflated polyethylene instead of single-glass panels.
Insights from Greenhouse Polyethylene Experts
According to Thomas Thizy, an expert in greenhouse polyethylene, double-inflated polyethylene film improves insulation through two main mechanisms:
- The dual poly layers act as a thermal barrier.
- The air trapped between the layers creates an insulating pad, preventing rapid heat loss.
Thermal-treated polyethylene films, enhanced with ethylene vinyl acetate (EVA) and mineral additives, further improve insulation by blocking long infrared radiation at night.
For optimal performance, Thizy recommends a 7.2-mil thermal film with thermal treatment on both layers and an 8 cm air gap between them. This combination significantly enhances greenhouse insulation beyond just increasing film thickness.
Strategies to Reduce Heat Loss
1. Installation of Thermal Screens
Deploying thermal screens at night adds an additional barrier against heat loss. Screen quality varies, so selecting the right material is key.
2. Insulating Foundations and Under-Crop Areas
Installing insulation around the greenhouse foundation and under the growing beds reduces ground-level heat loss without compromising light levels.
3. Use of Windbreaks
Planting or installing windbreaks around the greenhouse minimizes convection losses by reducing wind speeds at the structure’s surface.
4. Dehumidification
Using dehumidifiers helps control humidity without excessive ventilation, thereby preventing unnecessary heat loss. This is particularly effective in semi-closed greenhouse systems.
5. Smart Ventilation Management
Optimizing vent openings based on climate conditions ensures efficient humidity control while preserving heat.
Maximizing Energy Savings with Thermal Screens
According to Rob Hanifin, a greenhouse climate expert at RIDDER, thermal screens are one of the most effective tools for reducing energy consumption in greenhouses. These screens trap warm air and reduce heating requirements by up to 40%, depending on the material and installation quality.
Winter Night Strategy
To maximize efficiency, Hanifin emphasizes:
- Ensuring thermal screens are completely closed at night to prevent heat leakage.
- Using knitted climate screens allows moisture to escape and help regulate humidity levels.
Key Considerations When Choosing Thermal Screens
Greenhouse managers should evaluate:
- Energy-saving potential
- Light transmission properties
- Humidity control features
- Compatibility with crop requirements
Emerging Trends in Thermal Screens
Modern thermal screens offer:
- Higher energy savings
- Improved light diffusion
- Enhanced flame-retardant properties
- Advanced climate control capabilities
The Importance of a Holistic Approach
Reducing heat loss requires a comprehensive strategy combining proper material selection, advanced climate management, and efficient energy use. Although initial investments in insulation and climate-control technologies may seem high, they provide long-term cost savings and environmental benefits.
By implementing these expert-backed solutions, greenhouse operators can enhance productivity, reduce heating costs, and promote sustainable agricultural practices.
This article has been created based on the Hortigen Insights by Sepehr Achard of iGrow News.
Further reading
Controlled Environment Agriculture - Greenhouses
The Future of Controlled Environment Agriculture: AI, Data Integration & Key Trends for 2025
The Global Future of Vertical Farming (2025–2035): A Scenario Analysis Across Continents
Controlled Environment Agriculture in the Mediterranean: A Sustainable Future
The Problem of Humidity in Greenhouses: Causes, Effects, and Solutions
10 Proven Ways to Make Greenhouse Crop Production More Sustainable and Efficient
Integrated Pest & Disease Management in Greenhouses: A Comprehensive Guide