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Best Way to Heat a  Greenhouse for Winter in 2024

Year-Round Greenhouse Heating with Outdoor Wood Boilers 

In the ever-evolving world of agriculture and horticulture, the pursuit of innovation and sustainability is vital. As we step into 2023, the demand for eco-friendly and cost-effective heating solutions, such as outdoor wood boilers, is more pronounced than ever. This comprehensive guide will explore the complexities of greenhouse heating, delve into the historical roots of wood heating in agriculture, and uncover the modern advancements that are revolutionizing the industry. Whether you’re an acreage owner, a greenhouse enthusiast, or passionate about sustainable farming, join us as we navigate the world of greenhouse heating with insights, tips, and a real-life success story (Portage & Main Boilers – Greenhouse Heating, 2023). 

Welcome to the future of greenhouse heating, where innovation meets sustainability, and where Portage & Main Boilers stands as a beacon of quality and reliability. 

Introduction to Greenhouse Heating 

In the world of modern agriculture, maintaining consistent greenhouse temperatures is not just a matter of convenience; it’s a critical factor that directly impacts the growth, health, and yield of crops(Binversie & Nell, 2018a). Whether nurturing delicate seedlings or ensuring the year-round production of tropical plants in temperate regions, the ability to control temperature within a greenhouse is paramount. It’s a delicate balance that requires precision, reliability, and adaptability, and it’s a challenge that Portage & Main Boilers is committed to solving. 

Year-round greenhouse and home heating in general present their own unique set of challenges. From the biting cold of winter to the unpredictable fluctuations of shoulder seasons, greenhouse and farm owners must navigate a complex landscape of climatic variables. Traditional heating solutions often fall short, either in terms of efficiency, sustainability, or cost-effectiveness. The quest for a heating solution that can seamlessly adapt to these diverse challenges leads us to a timeless yet innovative option: outdoor wood boilers (eXtension Farm Energy, 2019). 

Fuel Type Comparison in Order of Cost 

  • Wood Chips: An economical and renewable option, wood chips offer a balance of cost-efficiency and sustainability. They are often locally sourced, reducing transportation costs and carbon footprints.
  • Cordwood: Another renewable option, cordwood can be an economical choice for those who have access to their own wood supply. It’s a versatile fuel that aligns with the principles of self-reliance and environmental stewardship.
  • Pellets: Manufactured from compressed sawdust, pellets offer a cleaner burn and higher energy density. While slightly more expensive than wood chips and cordwood, they provide a convenient and efficient heating solution.
  • Fossil Fuels: While fossil fuels like oil and natural gas are commonly used, they are often the most expensive and least sustainable option. The environmental impact and fluctuating prices make them a less attractive choice for forward-thinking greenhouse owners.andscape of greenhouse and home heating is a complex interplay of

The Evolution of Outdoor Wood Boilers for Greenhouses 

The history of wood heating dates back to the 16th century in Europe, where the first metal wood-burning stove was invented. However, it wasn’t until the Industrial Revolution, nearly 200 years later, that wood stoves became more common. The early settlers resisted the switch from open hearths to wood stoves, but practicality won out, and by the 20th century, 40 million American homes were heated with wood stoves (The Old Farmer’s Almanac – Wood Heating, 2023). 

Transition to Modern Advancements 

The popularity of wood stoves in homes waned but resurged in the 1970s, affirming the old country saying, “Wood warms you thrice—when you chop it, when you stack it, and when you burn it”. This resurgence laid the foundation for the modern evolution of wood heating, leading to technological advancements that provide efficient and sustainable solutions for farms and homes with greenhouses. 

Modern wood boilers are designed with efficiency, sustainability, and user-friendliness in mind. They come equipped with features like automated feed systems, advanced combustion technologies, and sophisticated controls that allow for precise temperature regulation. These innovations have made wood boilers a viable and preferred heating option for many greenhouses, farmers, and residential homes (eXtension Farm Energy, 2019).  

Portage & Main Ultimizer and Polar Furnace’s G-Class 

Portage & Main’s Ultimizer series and Polar Furnace’s G-Class are examples of state-of-the-art wood boilers that have revolutionized greenhouse heating. The Ultimizer series is known for its robust construction, high efficiency, and low emissions, making it an ideal choice for those seeking a dependable and environmentally friendly heating solution.

On the other hand, Polar Furnace’s G-Class offers a unique combination of performance, versatility, and ease of use, with models designed to suit various heating needs. Both these product lines reflect the ongoing commitment to innovation and quality that characterizes the modern wood boiler industry, providing greenhouse owners with reliable, cost-effective, and sustainable heating options (Portage & Main Boilers – Ultimizer Wood Series, 2023; Portage & Main Boilers – Polar G-Class, 2023). Also woodchip LCB 300 & 600 for automatic feeding of wood chips. 

Benefits of Using Wood Boilers for Greenhouse Heating 

Wood boilers have become an increasingly popular choice for greenhouse heating, offering a range of benefits that align with the growing emphasis on sustainability, efficiency, and cost-effectiveness. From being an eco-friendly solution to providing consistent and reliable heat, wood boilers, especially those like Portage & Main’s Ultimizer series, have proven to be an indispensable asset for modern greenhouses from smaller to larger commercial units. Let’s explore these benefits in detail: 

Eco-Friendly and Sustainable Heating Solution  

  • Renewable Fuel Source: Wood is a renewable and abundant fuel source, making wood boilers a sustainable heating option. 
  • Carbon Neutral: Burning wood releases the same amount of carbon dioxide that the tree absorbed during its growth, resulting in a net-zero carbon footprint. 
  • Reduces Dependence on Fossil Fuels: By using wood as a primary fuel, greenhouses can reduce their reliance on fossil fuels, contributing to environmental conservation. 

Cost-Effective Heating in the Long Run 

  • Lower Fuel Costs: Wood, especially if sourced locally, can be a more economical fuel option compared to traditional fossil fuels. 
  • Long-Term Savings: Though the initial investment may be higher, wood boilers offer long-term savings through reduced heating bills. 
  • Potential for Government Incentives: Some regions offer incentives for using renewable energy sources, further enhancing the cost-effectiveness of wood boilers.  

Consistent and Reliable Heat Supply 

  • Steady Heat Distribution: Wood boilers provide a consistent and even heat supply, essential for maintaining optimal greenhouse temperatures. 
  • Independence from Grid Failures: By using wood boilers, greenhouses can ensure uninterrupted heating, even during power outages or grid failures. 
  • Adaptability to Different Weather Conditions: Modern wood boilers are designed to adapt to varying weather conditions, ensuring reliable heating year-round. 

Efficiency & Performance: Features of Portage & Main Ultimizer 

  • High Efficiency: The Ultimizer series is engineered for maximum efficiency, converting more fuel into usable heat. 
  • Advanced Combustion Technology: Utilizing cutting-edge combustion technology, the Ultimizer ensures clean and complete burning of wood.
  • User-Friendly Controls: With simplistic controls, users can easily regulate temperature and other settings, optimizing performance and convenience.
  • Versatility in Fuel Options: The Ultimizer series can burn various wood types, offering flexibility and ease of use. 

These benefits collectively make wood boilers, particularly the Portage & Main Ultimizer series, a compelling choice for greenhouse heating. By embracing this technology, greenhouse owners can align their operations with modern sustainability goals while enjoying reliable and cost-effective heating solutions.  


Setting Up an Outdoor Wood Boiler for Your Greenhouse 

Setting up an outdoor wood boiler for your greenhouse is a critical process that requires careful consideration of various factors. From choosing the right size and model to integrating it with existing systems, proper planning and execution are essential for optimal performance. Portage & Main’s Ultimizer series offers user-friendly and low-maintenance features that make this process more manageable. Here’s a detailed guide to help you set up an outdoor wood boiler for your greenhouse: 


Choosing the Right Boiler Size and Model 

  • Assess Heating Needs: Determine the heating requirements of your greenhouse, considering factors like size, insulation, and climate
  • Consult Experts: Seek professional advice to select the right boiler size and model that meets your specific needs
  •  Consider Future Expansion: If you plan to expand your greenhouse in the future, choose a boiler that can accommodate the increased heating demand.  


Installation Tips and Best Practices 

  • Follow Manufacturer Guidelines: Adhere to the installation instructions provided by the manufacturer to ensure safe and efficient operation. 
  • Hire Qualified Professionals: Engage certified installers who are experienced in setting up outdoor wood boilers for greenhouses. 
  • Ensure Proper Ventilation: Ensure that the boiler is installed in a well-ventilated area to facilitate proper combustion and prevent any safety hazards. 


Integration with Existing Greenhouse Systems


  • Compatibility Check: Ensure that the wood boiler is compatible with your existing greenhouse heating systems, such as radiant floor heating or forced air systems. 
  • Seamless Integration: Work with professionals to integrate the wood boiler seamlessly with existing systems for uniform heat distribution. 
  • Monitor & Control: Implement monitoring and control systems to regulate temperature and humidity levels efficiently. 


User-Friendly & Low Maintenance: Features of Portage & Main Ultimizer

  • Easy Operation: The Ultimizer series comes with intuitive controls that make operation simple, even for those new to wood boilers. 
  • Low Maintenance Requirements: Designed for convenience, the Ultimizer requires minimal upkeep, saving time and effort. 
  • Durable Construction: Built with high-quality materials, the Ultimizer ensures long-lasting performance and reliability. 
  • Responsive Support: Portage & Main offers responsive customer support to assist with any questions or issues related to the Ultimizer series. 

By following these guidelines and leveraging the features of Portage & Main’s Ultimizer series, greenhouse owners can successfully set up an outdoor wood boiler. This investment not only enhances the efficiency and sustainability of greenhouse heating but also contributes to a more eco-friendly and cost-effective operation. 

Maintenance and Safety Considerations 

Proper maintenance and adherence to safety guidelines are paramount when operating an outdoor wood boiler for greenhouse heating. Regular upkeep ensures optimal efficiency, while following safety precautions minimizes risks and enhances the boiler’s longevity. Seasonal adjustments are also vital to adapt to changing weather conditions and heating demands. Here’s a comprehensive guide to maintenance and safety considerations: 


Routine Maintenance for Optimal Efficiency

  • Regular Cleaning: Periodically clean the boiler’s interior and exterior to prevent buildup of ash and debris, which can hinder performance. 
  • Inspect Components: Regularly inspect essential components such as the firebox, water jacket, and seals for wear and tear, and replace them as needed. 
  • Monitor Water Levels: Keep an eye on water levels and refill as necessary to maintain proper functioning. 
  • Professional Servicing: Schedule annual servicing to ensure that the boiler is operating at peak efficiency. 


Safety Precautions and Guidelines 

  • Follow Manufacturer’s Instructions: Always adhere to the manufacturer’s safety guidelines and instructions for operation and maintenance. 
  • Use Proper Fuel: Utilize the recommended fuel type and avoid using treated or painted wood, which can release harmful chemicals. 
  • Install Safety Features: Equip the boiler with safety features such as pressure relief valves and temperature gauges to prevent potential hazards. 
  • Maintain Safe Distance: Ensure that the boiler is installed at a safe distance from buildings and flammable materials to minimize fire risks.

Seasonal Considerations and Adjustments 


  • Winter Preparations: Insulate pipes and make necessary adjustments to prevent freezing during winter months. 
  • Summer Maintenance: During the summer, when the boiler may not be in use, drain and clean it to prevent corrosion and buildup. 
  • Adjust Settings: Modify temperature settings and other controls to adapt to seasonal changes in heating demand. 
  • Inspect Insulation: Check the insulation of the greenhouse and make necessary repairs to ensure efficient heating during different seasons.  

By implementing these maintenance and safety practices, greenhouse owners can ensure that their outdoor wood boiler operates efficiently and safely throughout the year. These considerations not only contribute to a more sustainable heating solution but also protect the investment in the boiler, ensuring that it continues to serve the greenhouse’s heating needs for years to come. 

Case Study: Tropic of Canada  

Keith, the visionary behind Tropic of Canada, had always been passionate about gardening. With a rich history as a production manager and grower for renowned nurseries across England, California, and Canada, he was no stranger to the challenges of cultivating a diverse range of plants.  



Greenhouse Tropic of Canada

When his property, spanning a third of an acre, began to house over 240 varieties of fruits, the need for an efficient and sustainable heating solution became paramount. The temperate fruit varieties, especially those in containers, required specific care during the harsh Canadian winters.   

After extensive research into various heating solutions, Keith’s quest led him to the Polarfurnace / Portage & Main Boilers. It’s unmatched efficiency, commitment to sustainability, and reliability resonated with Keith’s ethos. He was ensured that the diverse range of fruits at Tropic of Canada, from those espaliered outdoors to those sheltered in greenhouses, thrived throughout the year, reinforcing his decision as the right choice for his expansive garden. 

Link to his website : https://tropicofcanada.ca 

Old Firewood Shed

Conclusion: The Future of Greenhouse Heating

In an era where sustainability and self-reliance are paramount, the growing trend of wood boiler heating in agriculture is a beacon of hope for the future of greenhouse heating. The success stories, like Keith. Choosing a heating solution like Portage & Main’s Ultimizer is not just about investing in a quality product; it’s about joining a community that values customer support and satisfaction.

As we look towards the future, the role of wood boilers in greenhouse heating is poised to expand, driven by the dual goals of efficiency and sustainability. Explore Portage & Main’s innovative solutions today and take the next step towards a more sustainable future in agriculture.



Q. What are the main advantages of using wood boilers for greenhouse heating ?

  • Renewable and sustainable fuel source
  • Cost-effective in the long run
  • Consistent and reliable heat supply
  • Eco-friendly and carbon-neutral
  • Potential for government incentives

Q. What are the key considerations when choosing a wood boiler for a greenhouse?

  • Fuel type and availability
  • Boiler efficiency and emissions
  • Size and heating capacity
  • Initial investment and long-term savings
  • Local regulations and incentives

Q. How are outdoor wood boilers a sustainable heating option for greenhouses?

Outdoor wood boilers offer a renewable and carbon-neutral heating solution. They utilize wood, a renewable fuel source, and burn it efficiently, minimizing emissions. By reducing dependence on fossil fuels and maximizing energy derived from wood, outdoor wood boilers align with modern sustainability goals (Bailey Line Road, 2023).

Q. How do outdoor wood boilers adapt to different weather conditions, especially during winter on a farm?

Modern outdoor wood boilers are designed with advanced controls and features that allow them to adapt to varying weather conditions, including the harsh winter months on a farm.

Proper insulation, temperature settings, and seasonal adjustments ensure reliable heating year-round. Whether facing the biting cold of winter or the unpredictable fluctuations of shoulder seasons, outdoor wood boilers provide a consistent and adaptable heating solution, ensuring the well-being of plants and the efficiency of farm operations.

Q. What incentives or government support are available for farms using outdoor wood boilers for heating?

Some regions offer incentives or grants for using renewable energy sources like wood boilers on farms. These incentives may include tax credits, rebates, or grants that can offset the initial investment cost. It’s advisable to consult local authorities, energy agencies, or agricultural extension services to understand the specific incentives available in your area.

Taking advantage of these incentives can make the transition to outdoor wood boilers more affordable and aligns with broader goals of promoting renewable energy and sustainable farming practices.


Farm-Energy. (2019, April 3). Wood heat for greenhouses – farm energy. https://farm-energy.extension.org/wood-heat-for-greenhouses/

A brief history of the woodstove. (n.d.). Almanac.com. https://www.almanac.com/brief-history-woodstove

SteveM. (2021). Outdoor Wood Boilers are Part of a Sustainable Future. Baileylineroad. https://baileylineroad.com/outdoor-wood-boilers/

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About Portage & Main

Our head office is located in Prince Albert, Saskatchewan, Canada. Our dealer network spans North America and we would be glad to put you in touch with one of our knowledgeable agents. Our staff oversees the development of new products, monitors production, designs heating systems, and offers tech support for installers. All our wood furnaces are designed for installation outdoors and deliver wood heat indoors.







(306) 922-1722


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