Wood Boiler
In today’s fuel market, buying propane can get expensive. While this home is heated principally with a propane boiler that heats a fully zoned radiant floor system and domestic hot water, there is an outside wood fired boiler that adds economy to the equation. The wood stove - located midway between the wood shop and the main house - heats water that is circulated through a heat exchanger in the boiler room. This exchanger, located “upstream” from the main boiler, preheats the water returning from the floor or hot water exchanger. The maximum temperature of the boiler is set to 170 degrees F. When the wood stove is active and water is being circulated through the floor or domestic water exchanger, it maintains a temperature above the startup temperature of the inside boiler, and no propane is used. If the outdoor stove drops below a certain point (about 120 degrees F), the indoor propane boiler takes over and heats the home normally.
Last winter was a particularly cold year. It was the first year of operation for this wood stove system, so exact wood requirements are not known. We estimate that we used around 12 cords of wood. This property will sustain that level of consumption for many years, which would provide economical heating for anyone willing to get a little exercise in the forests in summer. Wood preparation is easy too. The logs are best cut about 2 ½ feet in length. Splitting is not necessary unless the logs are over about 1 foot in diameter. Handling of wood in this size is easy, and the repetitive steps of moving, stacking, and loading wood when these larger sizes are use are reduced. For the money saved, the work involved in using this stove was not an issue.
Remember that this boiler system is not the primary heating system. If wood is not added to the boiler and the fire goes out, the propane system in the boiler room will take over. This is especially useful if you're going to be away for a period of time and won't be able to load the wood stove.