Why one legendary company is right-sizing its steam after conducting a 5-year ROI analysis → Now their steam generation will align with their production needs—not the other way around.
Against the Green Mountains in Northfield, Vermont, family-owned Cabot Hosiery Mills has been knitting premium socks for more than 40 years. It’s an ardent skill passed down from father to son for three generations.
The company has built a global reputation making something surprisingly complex: socks. But not just any socks — Darn Tough Vermont® socks — the company’s ever-growing line of premium, category-specific, performance-fit, American-made socks backed by an unconditional lifetime guarantee. To say that’s unusual is an understatement.
The company has always done things differently. While competitors moved manufacturing overseas, Cabot Hosiery doubled down on American craftsmanship. The company and its employees are dedicated to being STILL Made in America, and particularly in Vermont.
Still, even the most principled operations face modern manufacturing realities, such as growing product demand, rising energy costs, and, for Darn Tough Vermont, a fragmented sock finishing process.
Knitting was done at the original Northfield Mill, while sock finishing—steaming, drying, pressing, and boarding—was conducted at one of their other facilities, located three miles away. That’s because steam is required to help set the fiber and knit structures of the socks, and two 100 BHP Johnston fire-tube boilers needed a larger space than what was available in the Original Mill.
To gain necessary efficiencies, the dual-location setup had to change.
- It made logistics more complicated
- It limited production speed, and
- It caused inefficiencies that were roadblocks to achieving the high standards and growth goals for the Darn Tough Vermont brand.
“The current equipment we had was operating okay. We weren’t looking to replace it for mechanical reasons. We were replacing a process that no longer made sense. It’s about operational efficiency and fuel consumption.” — Clayton Lamson, Cabot Hosiery Mills
One Building—One Smart Move
Darn Tough Vermont had recently made a significant advancement in the finishing process, which allowed them to bring the sock finishing process to the Original Mill.
To determine the right steam equipment for the job, Clayton Lamson, Director of Engineering, Facilities, and Safety at Cabot Hosiery, contacted Matt Pollack, Sales Engineer for Clayton Industries. The company had previously used Clayton steam generators in another facility and had good experiences with the technology and the service team.
They arrived at a plan that would replace the two Johnston 100 BHP fire-tube boilers currently in use at the finishing location with two Clayton 50 PHB Steam Generators with a Super Economizer. Their small footprint would enable the entire production, from setting up the cones of yarn to packaging the socks and palletizing the cases, to take place in the same facility.
Why Steam Matters in Making Darn Tough Vermont Socks
When it comes to the Darn Tough Vermont brand, sock finishing is more than a mechanical step—it’s a craft.
Socks are knit one sock at a time, then washed, steam dried, and “boarded,” which involves placing the socks on aluminum foot-shaped forms to give them their final shape and size. There are 24 boards per finishing machine. Steam and its high heat help set the fibers to the shape.
“Steam helps set the fiber and knit structure,” said Lamson. “Too much moisture, and the sock loses its integrity. Too little, and it won’t conform to the board. Our finishing depends on repeatable, responsive high-quality steam, and that’s what Clayton’s generators are engineered to provide.”
Why Clayton Matters in Making Darn Tough’s Steam
- Right-sized footprint: The Clayton system is compact enough to fit in the space. Two Clayton 50 BHP generators and their feedwater systems fit in the same space as one Johnston boiler.
- Steam-on-demand: Clayton generators reach full steam in just 15 minutes, compared to two hours or more for conventional boilers. This is a big deal in a stop-and-go manufacturing environment
- High-efficiency operation: Operating at 85% efficiency and 90% load, the Clayton generators outperformed the Johnston boilers, which ran at 75% efficiency and 50% load. With the added Super Economizers, heat recovery is maximized, further reducing fuel use and emissions.
- High-quality, dry steam: Clayton equipment produces high-quality steam that’s 99.6% dry heat. Conventional boilers have too much moisture, which can compromise product quality.
- Precision heating and smart modulation: “Manufacturing socks is process-driven: heat, dry, press,” said Lamson. “To lock in the Darn Tough legendary comfort and fit, we have to control the heat to the socks to 385°. We need a steam system that can provide steam when it’s needed and be idle when not in use.” Pollack confirmed that the Clayton equipment is fully modulating and automatically adjusts the heat up or down, based on steam demand. Compare that to conventional boilers, which are high-fire or low-fire, resulting in high energy costs and increased wear and tear. The boiler has to work harder, and it burns a lot more fuel. In that respect, Clayton generators have a longer expected lifespan.”
- Propane-ready: In mountainous Vermont, a rock ledge prevents pipelines from bringing natural gas to the area, so the equipment has to be propane-fired. The Clayton units are easily configured to operate efficiently on propane—a key differentiator.
- Expected reductions in emissions: Clayton generators support Cabot Hosiery’s sustainability goals, and the equipment could help maintain good air quality inside the facility.
- Built-in redundancy: By installing two Clayton units instead of one large boiler, if one unit is offline for maintenance, the other can continue production. This redundancy ensures uninterrupted finishing, which helps get the products out the door.
Data-Driven Decision Making: 5-Year ROI Analysis
To provide Cabot Hosiery ownership with the data that they needed to make a decision, Pollack and Lamson developed a 5-year ROI analysis comparing the current Johnston system to the new Clayton solution. Projections indicated that the system would pay for itself through energy savings alone. The project is currently in the installation phase, with a go-live target of January 2026.
(See the complete Step-By-Step Analysis detailing every data point. It demonstrates how Cabot Hosiery—or any company—can use a projected analysis to make a data-based decision for purchasing the right equipment.)
Operating Assumptions
- Operating schedule: 116 hours/week = 6,032 hours/year
- Fuel: Propane $1.58/gallon
- Efficiencies:
- Johnston Boiler: 75%, running at 50% load
- Clayton Generator: 85%, running at 90% load
- Fuel energy content: Propane at 91,502 BTU/gallon
Pollack noted that ultimately, the 5-year projections were the most significant factor in the decision. The upfront costs may be higher, but the energy savings and maintenance costs made it an easier decision.
The Right Fit—for Socks and Steam
This isn’t just a boiler replacement project—it’s an operational transformation. By installing two Clayton 50 BHP Steam Generators with Super Economizers, Cabot Hosiery Mills is not only saving fuel and floor space, but it’s also creating a lean, more responsive, sustainable, and reliable production line.
According to both Lamson and Pollack, the takeaway for other manufacturers is clear: don’t default to what you’ve always used. When choosing a boiler system, thoroughly understand your needs rather than defaulting to a traditional system.
Lamson advises, “Right-size the system by understanding the steam demand sequencing and how that can be influenced to even out the peaks and valleys.”
Pollack agreed. “Plant and facility engineers looking to replace or modernize steam systems shouldn’t default to fire-tube boilers because they’re familiar. In a demand-sensitive process like sock finishing, steam on demand with modulation is a far better fit.”
For manufacturers with steam-critical processes, especially in industries where precision, energy use, and environmental impact are under scrutiny, the Cabot Hosiery Mills and Darn Tough Vermont story offers a blueprint worth following.
