How to Compare Hydronic Wood Fired Boilers

Hydronic wood-fired boilers provide hot water for heating systems and plumbing fixtures throughout the house. These units sit in outdoor structures which resemble little metal sheds and may burn traditional firewood or wood pellets for fuel. Just like any dwelling heating system, hydronic boilers represent a major investment. While shopping for hydronic wood boilers, consider things such as heat output, fuel requirements and how each unit will likely impact the environment to pick the ideal unit for your home.

Find the Right Size

Manufacturing companies frequently rate hydronic wood boilers based on how many square feet of living space they are designed to heat. When comparing these units, begin by estimating the total square footage of your residence. Add 25 percent for this figure when you plan to utilize your boiler to heat more than 1 building, such as the house and the garage. Add another 500 square foot if you plan on using your unit to heat water for your home. Finally, keep in mind that nearly all of these units have been sized for rooms using 8-foot ceilings. If your ceilings are 10 feet tall, then add another 25 percent for your square footage. Once you’ve calculated how many square feet you need to heat based on these recommendations, then choose a unit designed to heat a space of this size or larger.

Compare Fuel Types

Not all of wood-fired hydronic boilers are designed to burn a single type of wood. Some are constructed to handle traditional logs or firewood while others are built to burn only wood pellets. Prior to making a purchase, consider if you’ve got a ready supply of these fuels in your town. Compare prices of every fuel type, and consider that the work involved in getting each. For instance, using firewood in a boiler may require you to cut and stack the wood or to load the unit once a day or more. Using pellets may require normal deliveries, loading and storage. Weigh the costs and time involved for all these options to help narrow your selection.

Consider Smoke and Emissions

1 common complaint about hydronic wood-fired boilers relates to this thick smoke that they emit. Homeowners as well as neighbors and those residing in nearby can complain about the health consequences of this smoke. To minimize contamination, pick a boiler certified under the U.S. Environmental Protection Agency’s Burn Wise application. Units certified under this program contain a white label and will burn up to 90 percent cleaner than noncertified units. You may get a better idea of pollutant rates among both certified and noncertified units by checking the emissions rate, measured in grams per hour. Hydronic boilers certified under the Burn Wise program range from a low of 0.7 grams per hour to a high of 10.7 grams per hour as of January 2013. Refer to the specifications for each version to evaluate this info. If you decide not to spring for a clean-burning EPA-certified boiler, look for features which can help lessen the effect of smoke. The Wisconsin Department of Natural Resources recommends choosing a unit using a smokestack that’s 15 feet high or smaller so that smoke passes over the roofs of neighbors. Wisconsin DNR also suggests installing your hydronic wood boiler 300 to 500 feet away from any neighboring residences.

Assess Ease of Maintenance

The ashes created by wood-fired boilers must be removed regularly to ensure efficient operation. Maximize safety and convenience using a unit featuring a built-in ash removal door or drawer for easy access. Units without this feature can be more likely to cause burns and need more effort to maintain. You will also need to put the fire out every time you remove the ashes, then relight it once you’re done keeping the unit.

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