Hello Devin, To the best of my knowledge, it's not possible to set the initial temperatures in eQUEST/DOE2.2 (unless DOE2 ever becomes open source and you want to recompile the Fortran :) ). The method used by eQUEST is to assume that at hour 1, all previous hour loads and heat gains are 0, so in essence the initial temperatures are all 70 F for all zone and wall temperatures. It then iterates through the first 3 days a few times before starting the full simulation (I can't remember the exact number of iterations or number of days) using the results at the end of the 3 days as initial conditions at day 1. So the results you see on hour 1 of the hourly eQUEST reports are a result of this. This is a way to approximate realistic smooth initial conditions. I'm curious, are you finding that your finite-difference model only follows the eQUEST results when you give then exactly the same initial temperatures? I've always found the RF/weight-factor method in eQUEST to be very stable (possibly due to the linearization of radiation?), even if you give it crazy initial conditions, the results correct themselves within a week or so. Aaron Is it possible to alter the initial temperatures before a simulation? If so, where do I do this? Thanks for any help. I'll keep looking at manuals and hope to find something. -- Devin M. Rohan