olsen furnace model numbers
vanced features or higher efficiency. Efficiency Rating (AFUE) Usually embedded within the model code, such as 80, 90, or 96, indicating 80%, 90%, or 96% AFUE efficiency. Heating Capacity Expressed in BTU/h, such as 24, 36, 48, etc. Alternatively, in tons (1 ton = 12,000 BTU), such