Hi all,
I am working on a project to see whether we can improve energy consumption in a large building by switching off the HVAC overnight when attendance is low (its an airport terminal, 24/7 operation).

Clearly I can turn things off easily but I don't know how "hard" the system will have to run to "catch up" in the morning.

I have lots of data from the Building Management System logs so I can estimate electricity consumption via the plant room equipment that is running (I dpon't have enough meters to do it that way). If we make a change to the HVAC operation schedule we can log the same data points and collect plenty of measurements.

However, the ambient weather conditions are obviously a factor. If its "abnormally" hot or cold, I may not determine any difference in energy consumption if I just look at the "headline" figures.

So I think my problem statement is something like: "Energy Consumption after the HVAC schedule changes is lower PROVIDING there is no significant change to the ambient temperature profile".

If I have a distribution of energy figures before and after the HVAC schedule changes, I can test for differences in the means (for example Ho: Mean Energy After = Mean Energy Before). But how do I account for the ambient temperature?

Any ideas would be appreciated.