Keep the heat high and energy bills low with an outdoor wood furnace

As homeowners increasingly seek energy-efficient, costeffective heating alternatives, outdoor wood furnaces have emerged as a top choice in North America, where renewable lumber resources are abundant. Central Boiler, based in Minnesota, is North America's largest manufacturer of outdoor wood furnaces. The company offers UL- and CSAcertified models and heating solutions tested to European EN 303-5 standards, renowned for their efficiency and cuttingedge technology.

Central Boiler’s commitment to innovation and sustainability has played an essential role in the company’s success. These values aligned with Grundfos’s, making the relationship synergetic from the start. A collaborative partnership with Grundfos has produced solutions that address reliability issues with circulation pumps, as previous failure rates on system circulators were higher than Central Boiler would have liked. A pump is a crucial component of their outdoor wood furnace systems, and the goal was to find a pump with zero failure rates.

Over a 9-month period, Central Boiler conducted extensive research for a higher-quality, energy-efficient, more reliable circulator. When they narrowed the decision to Grundfos, they were invited to Denmark to see the production facility in person. Central Boiler found they could replace the troublesome circulators with the Grundfos UPMS 20-58 and 20-78 ECM pumps without altering their installation practices. The result? A non-existent failure rate to date. The adoption of ECM pump technology was a testament to Central Boiler’s commitment to being an industry leader, as the US Department of Energy mandates that all pumps must be ECM by May 2028.

"The Grundfos UPMS 20-58 and UPMS 20-78 ECM pumps work tremendously well. We have had no failures in the 1,800 pumps we’ve installed so far, and growing steadily. They offer exceptional performance, efficiency, and reliability," said Rodney Tollefson, Vice President, Central Boiler.

Traditional home heating systems in North America often use forced air, which can be costly, dirty, and reliant on fossil fuels like natural gas. Fueled by wood—a renewable resource—outdoor wood furnaces provide a sustainable alternative. They are EPA-certified, and residents who install one can receive a tax credit. Wood furnaces offer increased comfort through hydraulic heating, allowing for zone heating or simultaneous heating of multiple homes and small buildings. Hydraulic heating is cleaner and improves air quality by reducing airborne particles.

"These systems rely on pumps to operate on a constantuse basis, 24/7, which is why the pump is such a critical component," explained Tollefson. “The pump, mounted onto the furnace, prevents water stratification and moves heated water from the furnace to the residence. Without a functioning pump, water cannot be moved.”

Grundfos ECM pumps consume up to 85% less energy than traditional pumps, saving homeowners money on electric bills—a key factor as energy rates continue to climb. The ECM motor allows for speed regulation, unlocking additional energy savings.

"Grundfos’s quality control, the performance of the pumps, and their ability to meet timelines and answer all our questions have been most impressive," Tollefson noted.

A reliable circulator pump is essential for efficient and consistent operations of an outdoor wood furnace. Central Boiler’s experience demonstrates that choosing Grundfos circulators significantly enhances the performance and reliability of their outdoor wood furnace systems, ensuring consistent warmth and lower energy bills for their customers.