The job of working with furnaces and air conditioning units should usually be left to a professional.  However, there are several minor repairs that you can make which will save the cost of a service call. 

     Servicing a furnace or an air conditioner calls for a few basic tools:  a screwdriver, a wrench, a hammer, and pliers.  A malfunctioning furnace can be a great fuel waste.  It should be cleaned annually by you or by a professional.  For example, as carbon deposits accumulate on an oil furnace’s heating tubes, they act as a covering insulation.  This causes the heat to go up the chimney.  The serviceman should also analyze the carbon dioxide content of the gas in the flue (enclosed passageway).  If carbon dioxide is high, the combustion is satisfactory.  If you hear rattles in the furnace, the fan, pump, or boiler may be defective and need servicing.  And, if the chimney is smoking, the burner elements on the furnace may need to be adjusted.   

     Also duct work from the furnace should usually be insulated to provide heat more efficiently.  Air conditioners need filters to work properly.  If you have a central air conditioning system, it should be mounted level and the connections should be tight. 

     Keep thermostats constant.  The best daytime setting is 68 degrees in winter, 78 degrees in summer.   Do not set the thermostat at extreme high or low levels; moving the setting up and down actually costs money.    If you are going on vacation or leave the house for a few days, set the thermostat at 55 degrees.  Every degree over 70 adds 3% to your heating charges.  If you need heat in a hurry, move the thermostat to 72 degrees; you will gain heat as quickly as you would by setting the thermostat at 80 degrees.  The higher setting will only overheat the house.  However, if you have a 2-sage warm air system, you can heat a specific area faster with a high setting.

     A dirty thermostat may malfunction and thus make the rooms in your home too hot or too cold.  Inspect the working parts of the thermostat at least once a year.  If the parts are dirty, clean them with a soft brush; do not oil the thermostat.  Room thermostats should be located where the air circulates freely and away from fireplaces or room air conditioners, so that your original settings will remain constant.  If the thermostat in your home is located next to hot water pipes, in direct sunlight, near exterior doors, or next to heating products, you should move it.