How a modern wood heating system transformed this farm’s bottom line
Mettowee Mint garden center in Dorset is like a candy store for plant people. The symphony of colors and smells draws visitors into the greenhouses, where they can wander in a happy trance with a fresh cup of coffee from the in-house cafe.
The 4.5-acre garden center has something for everyone: Fresh bouquets, hanging baskets, even a tulip CSA. The greenhouses keep the plants cozy year-round.
Owner Sarah Linford always dreamed of becoming carbon neutral. But she wasn’t exactly sure how she’d get there. Heating greenhouses through the cold Vermont winter requires a lot of fuel. Eventually, Linford realized that the cost of heating the greenhouses was more than she was making in plant sales over the winter, threatening to shut down that part of the business. It was a financial wake-up call. If Linford wanted her business to remain viable, she had to find a more affordable heat source.
It turns out the cheaper heat source—wood—is also more climate-friendly and supports the local economy.
Mettowee Mint is in the Mettowee Valley of Vermont, a region with a lot of working forests. Working forests are a critical element of the Vermont landscape. More than generating revenue from timber sales, working forests contribute to a healthy ecosystem through forest management plans that prioritize things like species and age diversity. In turn, Vermont’s forests are more resilient to climate change.
If Linford bought wood from the nearby hills, 80 cents of every dollar would stay in Vermont, compared to 22 cents for fossil fuels. The price of wood is also generally more stable than the price of oil or propane. “We could either pay members of our community or pay fossil fuel companies,” Linford says. The choice seemed clear.
“We could either pay members of our community or pay fossil fuel companies.”
With expert guidance from partners including the Vermont Department of Forests, Parks & Recreation, Efficiency Vermont, and SunWood Biomass, Linford chose to install two high-efficiency cordwood gasification boilers.
Efficiency Vermont provided free energy modeling and economic analysis to show how much money and energy Linford would save with her new system. The results were promising: Mettowee Mint is now saving almost $9,000 a year on fuel costs, along with 57 tons of CO2.
Mettowee Mint was able to get 75% of the upfront project costs covered through a combination of grants, loans, and incentives. That financial support was instrumental to making the project a reality.
Advanced wood heat is highly efficient. There are boilers designed to burn pellets, woodchips, or cordwood. Linford chose cordwood because it was cheapest and least processed, meaning she knew exactly where it was coming from. Linford already had relationships with foresters in her community. To meet the demand for 25 cords of wood annually, she now buys from multiple sources.
Linford’s boilers use a downdraft system. The cordwood burns in an upper chamber, and then the wood gas is pulled down into a second combustion chamber where it burns again. This double-combustion process extracts as much energy as possible from the wood fuel. The heat generated by the boilers is used to warm water in two storage tanks.
Mettowee Mint has a mini district system, with boilers providing heat to multiple buildings via insulated underground piping. One of the district zones utilizes a radiant slab to efficiently heat a greenhouse. Linford loves the slab. “It works so well because it’s a heat sink,” she says. Instead of heating a high volume of air in a relatively uninsulated space, the radiant slab can keep the greenhouse warmer using the same amount of fuel.
Managing the cordwood is labor intensive, and Linford has experimented with all manner of workflows: buy the wood bucked and split; buy log lengths; store it in stacks; store it in bags. One of the primary challenges is getting the wood dry enough to burn efficiently in the boiler. Twenty-five cords is too much to have multiple years’ worth of wood drying in rotation on-site. To solve that problem, Linford is installing a kiln to season the wood.
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Pellet & Cord Wood Stoves Now in her third winter with the wood boilers, Linford is thrilled that the system can keep up on all but the most frigid days. Those days are handled with a propane backup. “We’re so proud that we haven’t used any fossil fuels,” she says.
When customers wander around Mettowee Mint, Linford says the advanced wood heat is “part of the experience.” Beyond feeling the delightfully warm slab, customers can see how local wood is a viable heating source that supports the community. After walking by the stacked cordwood outside, customers might come across a poster explaining how the boiler works. They might also see a tag on a plant showing that it was grown right here in Vermont, which is a lot less resource-intensive than an imported plant. Customers might join the tulip club, a revenue source which Linford says wouldn’t have been possible with the old propane system.
Overall, Linford is happy with her new heating system. “There has been a learning curve,” she says, but she’s getting the hang of it, and she hopes other Vermont businesses will be inspired by her example.
