Renewable, Large-Scale Heating

Growers Network burns some trees with Chuck Gagner, CEO of Woodmaster. Let’s find out how to support the environment and reduce our energy load.

The following is an interview with industry experts. Growers Network does not endorse nor evaluate the claims of our interviewees, nor do they influence our editorial process. We thank our interviewees for their time and effort so we can continue our exclusive Growers Spotlight service.

To skip to any section within this article, click the links below:

  • Wood-Burning Boilers
  • Burning Cannabis
  • About Woodmaster and Chuck
  • Resources
  • Comments

  • Wood-Burning Boilers

    Well, every building is unique, and greenhouses require a lot of heat per square foot, distributed relatively evenly. To that end, we typically hire an engineering firm to go into large greenhouses to determine how best to lay the pipes and distribute the heat. Pipe sizing and gallons of flow are very important to satisfy the heat requirements of a building. It’s not enough to just have a boiler that produces the “correct” BTUs.
    Our most common sales occur in the upper half of the United States, from OR to NY and into the Canadian provinces of Northwest Territories and New Brunswick. We also have boilers in the southern states of New Mexico and Nevada and anywhere that can experience temperature extremes. I would say as far north as Yellowknife and as far south as New Mexico.
    There’s actually a few reasons why you might want a wood furnace over another heating method:
    1. The price of wood as a fuel is extremely stability. Biomass fuel prices are very consistent, to the point of almost being flat. Heating oil and propane can have very volatile pricing comparatively.
    2. If you care about investing in your local economy (and you should), then biomass fuel is the way to go. Instead of paying to some oil processing plant, you’re paying your local timber industry.
    3. It’s good for the environment. As long as the timber company supplying the biomass replaces what it cuts down, there’s a net zero carbon footprint. Wood pellets and wood chips burn very clean and you can use that ash as a fertilizer.
    4. Burning biomass opens up more options to your fuel source. You can buy processed premium pellets or wood chips. It’s really your decision. Ash removal is automatic and reduces cleaning to a few hours per month.


    1. Wood chips require more attention. Unlike fossil fuels and wood pellet, there is a bigger chance of foreign matter getting into the fuel and causing a problem. Since wood pellet is just sawdust that has been compressed together, it’s unlikely to contain foreign matter.

    Burning Cannabis

    AHRI is an organization that tests many different materials as pellets for burning, including corn, straw, hay, and more. Typically those products carry a lot of ash content, whereas a premium wood pellet only carries 0.5% ash. Wheat straw, for example, might be as high as 6% ash.

    As for cannabis specifically, I don’t know what kind of ash content would be produced. High fiber content tends to burn well, so in theory cannabis should also burn relatively well. And in theory, you could use whatever ash you get for nutrients if you do some remediation on it to make sure it’s balanced.

    Editor’s Note: Update from Chuck! He found that hemp stalks contain 0.3% ash and 8500 BTU/lb, making it as good as premium wood pellet.

    Generally no. A boiler might be inappropriate for an indoor grow that is generating enough heat via its lights. Now, if lights aren’t able to satisfy the heat demand because of frequent ventilation, then a boiler might be handy. Additionally, if you want the heat to originate in the root zone, a boiler might be useful.

    About Woodmaster and Chuck

    Woodmaster manufactures commercial boilers intended for large applications, typically greenhouses. Most greenhouse growers choose to heat their growing spaces with either furnaces or boilers, so that’s what we do.

    As our name implies, our boilers burn wood instead of an oil-based product or natural gas. They’re designed to be completely automated with premium wood pellets (which are produced by compressing sawdust with a binding agent). Because the pellets use a renewable fuel, they are a cost-effective and environmentally-friendly way to heat large facilities.

    The cannabis industry came to our attention because we’re always looking for industries that require large-scale heating solutions. Every business owner wants to know how to make money and save money, and we’re here to help them save money.

    Prior to founding Woodmaster, I was a farmer. At the time, I wanted an outdoor wood furnace that would pipe hot water into my house without all the fire risk that conventional furnaces had. So I built one that was contained away from the house but piped hot water in, significantly reducing any fire risk.

    A lot of my friends and extended family saw what I had done, and they wanted one too. And that’s where Woodmaster was born. We started building heating solutions for the home market, but soon realized the commercial market had a vacancy for large-scale biomass fuel.

    I don’t think I know of any competitors in the outdoor wood-burning furnace industry that offers commercial-scale boilers. It’s what really sets us apart. Our complete WoodMaster line, which includes cordwood, wood pellet and wood chip products, are available in sizes from 100,000 BTU to 6.8 million BTU and can fit the needs of hobby farmers to commercial growers!

    And beyond that, we pride ourselves on service. We educate every dealer who sells our products on maintenance and troubleshooting, so that no matter where the customer is, they can have a local service person. The product is extremely durable and dependable, and requires minimal cleaning if you’re using premium wood pellets. You can, of course, use green wood and other less “pure” biomass fuel sources, but you will see additional fouling of the equipment.

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    Want to get in touch with WoodMaster?

    You can reach them via the following methods:

    1. Website:
    2. Phone: (800) 932-3629
    3. Email: [email protected]

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    About the Author

    Hunter Wilson is a community builder with Growers Network. He graduated from the University of Arizona in 2011 with a Masters in Teaching and in 2007 with a Bachelors in Biology.