Introduction to Greenhouse Heaters

Having a greenhouse offers gardeners and plant enthusiasts a unique opportunity to cultivate plants year-round, regardless of the external weather conditions. However, maintaining the right temperature within a greenhouse can be a challenge, especially during colder months. This is where greenhouse heaters step in to create an ideal environment for plant growth.

Types of Greenhouse Heaters

When it comes to greenhouse heaters, there are several types to choose from, each with its own set of advantages and suitability.

Electric Greenhouse Heaters

Electric heaters are a popular choice for smaller greenhouses due to their ease of use and clean operation. They come in various sizes and wattages, making them suitable for different greenhouse dimensions. They can be radiant heaters or forced air heaters. One advantage of electric heaters is that they don’t require as careful attention to ventilation as kerosene or propane heaters. Electric heaters are generally best for smaller greenhouses, but more powerful, convection style heaters can work for larger structures.

Propane Heaters

Propane heaters are known for their high heat output, making them ideal for larger greenhouses. They are efficient and don’t rely on electricity, providing a reliable heating source. Some propane heaters don’t require as much attention to ventilation, either. Having said that, it is a good idea to get a carbon monoxide detector with any kind of fuel-based heaters. Natural gas heaters are also available, but your greenhouse must be equipped for it. 

Kerosene Heaters

Kerosene heaters are cost-effective options and can produce substantial heat. However, you have to provide proper ventilation to ensure safe operation. Generally speaking, kerosene is not as popular as electric or propane for heating a greenhouse.

Solar Greenhouse Heaters

For those looking for an eco-friendly heating solution, solar heaters harness the power of the sun to warm the greenhouse. While they may not be as powerful as other options, they contribute to sustainable gardening. One way to make a solar greenhouse heater more effective is to use thermal mass to store the heat. A simple way to make thermal mass storage is to place black containers with water inside the greenhouse. 

Factors to Consider When Choosing Greenhouse Heaters

Selecting the right greenhouse heater depends on various factors that influence its performance and efficiency.

Size of the Greenhouse and Heating Capacity Required

When we talk about size, we mean the amount of heat the heater produces, measured in Btu/h (British thermal units per hour). To figure out the size you need, you’ll want to calculate it based on a few factors. First, multiply the surface area inside your greenhouse by the heat loss value of the covering material. The surface area is not just the square footage of the floor. It is the surface area of the roof and sides. A lower heat loss value means better insulation. Next, you’ll want to multiply this by the temperature difference between the outside temperature and your desired target temperature inside the greenhouse.

To make this process easier, you can use a size calculator like the one found at ACF Greenhouses. It provides heat loss values for common covering materials and does the calculation for you. For example, 4 ml. polyethylene has a value of 1.2. It loses lots of heat. Triple wall polycarbonate, by comparison, has a heat loss value of only 0.48.

Other elements of greenhouse design can affect your greenhouse heating needs. For example, underground greenhouses will be more efficient to heat than above-ground greenhouses because the earth is a great insulator.

Energy Efficiency and Operating Costs of Greenhouse Heaters

Consider heaters with high energy efficiency ratings to minimize operating costs and reduce environmental impact. This efficiency is one of the reasons for the popularity of propane heaters.

Safety Features and Certifications

Look for heaters with safety features like overheat protection and certification from relevant authorities to ensure safe operation.

Consideration of the Local Climate and Temperature Fluctuations

Understanding the climate in your area and the temperature fluctuations will help you choose a heater that can handle the coldest days.

Top Features to Look for in Greenhouse Heaters

When shopping for greenhouse heaters, certain features enhance their functionality and user experience.

Thermostat Control

A heater with a thermostat allows precise temperature regulation, preventing overheating or underheating of the greenhouse.

Fan or Blower

Heaters equipped with fans or blowers help distribute heat evenly throughout the greenhouse, ensuring all plants receive adequate warmth. While radiant heaters are fine for smaller greenhouses, larger structures generally require a forced air heater.

Timer and Programmable Settings

Having timer and programmable settings allows you to control when the heater operates, optimizing energy consumption.

Overheat Protection and Tip-Over Safety

Safety features like overheat protection and tip-over safety automatically shut off the heater in case of overheating or accidental tipping.

Benefits of Using Greenhouse Heaters

Investing in a reliable greenhouse heater can significantly benefit both the plants and the gardener.

Promoting Optimal Plant Growth

Greenhouse heaters create an environment that fosters plant growth by providing the necessary warmth and protection from harsh weather conditions.

Protection of Delicate Plants

During colder seasons, delicate plants are susceptible to damage. Heaters safeguard them from frost and cold-related stress.

Extend Growing Seasons

With a well-functioning heater, gardeners can extend the growing seasons, allowing them to experiment with different crops and plants throughout the year.

Installation and Maintenance Tips

To ensure the efficient operation of greenhouse heaters, proper installation and maintenance are essential.

Proper Placement of Greenhouse Heaters

Place the heaters strategically to ensure even heating and prevent any cold spots within the greenhouse. After setting up your heaters, check the temperature in different locations throughout the greenhouse to ensure even heating.

Regular Cleaning and Maintenance

Keep the heaters clean and perform regular maintenance to prolong their lifespan and efficiency.

Storage and Care During Offseason

During the offseason, store the heaters properly to protect them from dust and damage.

Personal Recommendations

Based on extensive research and expert opinions, here are some personal recommendations for greenhouse heaters that cater to different greenhouse sizes and budgets:

• Small Greenhouses (Up to 100 sq. ft.): For compact greenhouses, consider an electric heater with a low wattage output. The “Dreo Space Heater” is a reliable choice that provides gentle warmth for smaller spaces.
• Medium-Sized Greenhouses (100 – 500 sq. ft.): Opt for a propane heater like the “Dura Heat LPC25“, which offers sufficient heating capacity for medium-sized greenhouses.
• Large Greenhouses (Over 500 sq. ft.): Commercial grade convection heaters are pricey, but a great choice for large greenhouses. If your greenhouse is the size of 2 garages or more, you may need multiple heaters, strategically placed for even heating.
• Eco-Friendly Option: If environmental sustainability is a priority, go for the “Nakoair Solar Air Collector“, a solar-powered heater that helps reduce your carbon footprint.

Best Practices for Efficient Heating

To maximize the efficiency of your greenhouse heating system, follow these best practices:

• Proper Insulation: Ensure your greenhouse is adequately insulated to retain heat and minimize heat loss.
• Utilize Thermal Curtains: Installing thermal curtains can create a barrier to prevent heat from escaping at night.
• Ventilation: Adequate ventilation is essential to prevent excess humidity and maintain optimal growing conditions.

Additional Accessories for Greenhouse Heaters

Consider these additional accessories to enhance the effectiveness of your greenhouse heating system:

• Reflective Panels: Reflective panels can redirect and amplify sunlight during the day, reducing the reliance on heaters.
• Automatic Vent Openers: These devices automatically open and close greenhouse vents based on temperature, helping regulate heat without manual intervention.

Conclusion

Greenhouse heaters are indispensable tools for any serious gardener or horticulturist looking to extend their growing seasons and provide an optimal environment for plants. By understanding the different types of heaters available, considering essential factors, and following best practices, you can choose the perfect greenhouse heater to suit your specific needs. Remember to prioritize safety, energy efficiency, and the well-being of your plants when making your selection. With the right greenhouse heater, you’ll be able to enjoy flourishing plants and a bountiful harvest throughout the year.

Frequently Asked Questions (FAQs)

• Can I use a regular space heater in my greenhouse?
  • While you can use a regular space heater, it’s essential to consider factors like heating capacity, energy efficiency, and safety features that suit greenhouse conditions better.
• Are propane heaters safe for greenhouses?
  • Propane heaters can be safe for greenhouses, but proper ventilation and adherence to safety guidelines are crucial to prevent potential hazards.
• Can I leave the greenhouse heater on overnight?
  • It is generally not recommended to leave the heater on overnight without proper supervision. Consider using a heater with a built-in thermostat for controlled heating.
• How do I know what size of heater my greenhouse needs?
  • Calculate the heating capacity required based on the greenhouse’s size and the minimum temperature you want to maintain. Consult the heater’s specifications for guidance.
• Do solar-powered greenhouse heaters work during cloudy days?
  • Solar heaters may provide some heat on cloudy days, but their effectiveness will be reduced compared to sunny days.