Under Heating / Cooling — Is the efficiency an AFUE value or the Steady State Efficiency?
The efficiency one should enter in TREAT is the AFUE (a number which can only be guessed at for large steam boilers). Generally, the primary goal of your modeling is to calculate annual energy usage in the building. You verify it against billing, calibrate the model and predict annual savings from recommended improvement packages. For this purpose AFUE makes more sense then steady state efficiency, which may be significantly higher than AFUE, especially for older systems. If you use steady state efficiency you may underestimate annual energy usage and annual savings from improvements.
