You may wish to check your HVAC that typically use 30% to 45% of your incoming KW and are unbalanced most of the time. A dirty and or corroded unit can drop efficiency as much as 40%.  When it does this you use more KW and the unit cannot dehumidify.  There are several things you can do cheaply on existing units to rectify the problem.  One is to install a misting system that applies mist on the condenser fins while it is running.  This cools the fins.  Cool N Save and Evaporcool  are examples of manufacturers of this equipment.  You also may coat the same fins with a inorganic coating that prevents corrosion and by the nature of its surface tension keeps the unit cleaner without reducing heat transfer. MicroGuard is an example of such a product.

The building envelope plays a major role in the performance of the HVAC system because of air leakage and the performance of the thermal barrier (insulation).  The building should be under positive pressure and conditioned air is lost due to air leakage, but if it is under negative pressure, exterior air and moisture in the forms of both liquid water and water vapor will be drawn into the building.  This will add load to the HVAC system, as well as effect indoor air quality.  The glazing of the exterior wall will effect natural lighting of the interior, impacting the electrical load for lighting.  

Assessment of the air barrier can be done with air pressurization tests (both positive and negative) complemented with smoke testers and thermographic cameras.  The thermographic camera assessment will also identify voids in the thermal barrier, as well as trapped moisture in the enclosure assemblies indicating a problem with the water barriers.  

A retro-commissioning assessment should be done for the HVAC, controls, lighting, and building envelope to determine what improvements to each will have the greatest impact on reducing the energy use of the building.  Retrofitting the building envelope can be expensive and the ROI can only be determined on a case by case basis.