Dear Forums,

I am busy preparing a short talk for the Fall ASHRAE Energy Modeling
Conference. The topic is "An Approach for Calibrating Existing Building
Energy Models to their Utility Consumption".

As part of the preparation, I will address the issue of how much difference
might result in energy conservation measure savings predictions if you use
actual weather data for the billing period versus TMY data.

To get a rough idea how much variation there might be, I looked at Degree
Days for a span of years. What a variation! (for the city I'm studying at
least)

I am not yet sure how that affects total energy consumption - you'll have to
attend my presentation in Atlanta to find out J.

In the meantime, I am starting to think that existing building energy models
should use actual weather, not TMY data. Have any of you run similar
comparisons for existing building models?