Energy model result compared with measured data

Hi all,

I meet an interesting question by a comparison of elec energy consumption between simulation result and real data.

It seems that during the non-cooling season the real elec energy consumption(blue line) is constantly higher that simulation result(red line), but during summer not. However, the gas consumptions are in the same trend.
Could anyone help illustrate or give a hint of what could be the discrepancy between that gap? the hvac system is VAV w/Reheat without heatrecovery system.

Thank you very much!