Turn off circulation pumps during unoccupied times if no freeze conditions exist. Make sure that air handling unit filters are changed every 2-3 months, and that coils on the outdoor condensing unit and indoor heating and cooling units are kept clean. Check insulation levels on hot water piping and tanks. Heat loss from poorly insulated pipes can be a major loss of energy. Use natural gas heating if available.
Electrical heating is generally more expensive than gas heating.
Check control sequencing for multiple chillers and boilers. For light load operation, use the smallest and most efficient chiller or boiler available and avoid frequent equipment cycling. Make sure that simultaneous heating and cooling does not occur - verify proper operation of valves, dampers, and controls. Set back heating and cooling temperatures 30-60 minutes before the end of the day. Make sure ductwork is completely sealed and well insulated.