Gas fireplaces also reduce outdoor air pollution. Set back programmable thermostat. You want your house warmer when you are lounging in the evening or on weekends than at night when you sleep. By letting the electronics remember for you, it automatically saves energy. Furnace ductwork joints sealed with low toxic mastic.
Ducts lose air at each joint like a hole in a bucket.
Duct tape dries out in a few years and loses its sealing ability. Mastic stays flexible for much longer assuring that heat gets to where it is supposed to go. Sealed ducts are also safer keeping combustion gasses from entering the living space. Insulate hot and cold water pipes 3 feet from the hot water heater. By keeping water hot 24 hours a day, some heat is lost all the time.