Insulate your ceiling for savings on both heating and cooling costs. If the attic is accessible, add enough insulation to bring its R-rating up to at least R-38.
Install weatherstripping around exterior doors and along the threshold. If the gap at the bottom of the door is quite large, install a door sweep or a door shoe gasket.
Seal the gaps around pipes that connect to the house from the outside with expanding foam, which comes in convenient aerosol cans.
Keep fireplace dampers closed when not in use. This will stop the loss of warm air up the chimney all year long. Consider installing glass doors, which prevent burning ash and embers from flying free and reduces heat loss while the fire burns itself out overnight.
If you have a window air conditioning unit, remove it before winter to prevent heat from excaping through and around the unit. If it can't be moved, put a cover over it to prevent drafts.
Clean or replace the air filter once a month to maximize the efficiency of a warm air heating system. Also clean warm-air registers, baseboard heaters, and radiators several times a year.
Call your oil heat service technician. They can help you with a tune-up, system adjustments and system upgrades to increase the efficiency of your oil-fired home heading system and save you money.
Seal and insulate ducts. Ducts running through unconditioned spaces (attics, crawl spaces, and garages) that are not properly sealed and insulated can waste 25% of the energy used to heat and cool your home. Seal the joints with non-hardening sealant and insulate the ducts to an R-value of 6 for year-round energy savings.
Install a programmable thermostat to change the set point when you are at work or asleep. You will save about 2% of your heating bill and 3-4% of your cooling bill for each degree.
Hold a wet hand in front of outlets and light switches. If you feel a draft, install foam gaskets behind the plates to stop the leak.