Nic,

In addition to what others did mention, do not be surprised if (and this
is due to the increase of insulation) for internal load type of the
building actually you get higher energy use and, not the savings, relate
this explanation to the thermos: , higher R (resistance) value, less
heat transfer, smaller time lag differential through envelope, more
cooling internaly needed due to thermostat set points.
Note that your building location, climate data is very important as always.

Kind Regards,
Fisnik

Fisnik Rushiti, Dipl.Eng.Arch.