This session presents up-to-date theory and tools important in specifying low emissions high efficiency bio-thermal HVAC systems. Hydronic distribution incorporating advanced heat storage technology and digital firing control stabilizes combustion, eliminates excess cycling, and prevents low-fire air emissions without overheating occupied spaces. Principles apply to all types of solid biomass fuel. Woody biomass is an inexpensive, widely available and renewable heat source. By learning about equipment and processes already in commercial service engineers will be able to specify wood-fired HVAC systems without the risks, delays and extra cost of “re-inventing"