This is a not an easy question to answer because there is no exact science to the life expectancy of a heating system, rather a suggestive time frame of 18 to 20 years. The reason I say this is because a heating system that has not been serviced or repaired for a long period of time, will have undue wear and tear which will shorten its life expectancy.
I have seen instances where a furnace had to be replaced after 8 or 9 years because the burner section of the heating unit was misfiring and the controls were burned. The cost to replace the controls and restore the proper operation of the heating system was about the same cost as replacing the furnace in its entirety.
Like a car, heating systems need routine maintenance. Whether they are oil or gas fired, it is important that the burners ignite and burn properly, and that the flue gases are effectively discharged to the outside of your home. During a professional preventive maintenance call, a technician will check and clean the burner jets to ensure all debris and spider webs have been removed and that the flame is burning clean. The flue piping will be inspected to ensure there is no seepage of gases into your home and that the flue is properly vented to the outside of your home.
There are a few signs that your heating system is in need of attention. Is the gas usage on your bill increasing? That can be a sign that your heating system is inefficient. If you have a natural gas heating system, a yellow or flickering flame may be a sign that your burner is not firing properly and poisonous carbon monoxide can be drawn into your home.
Other possible signs of carbon monoxide are streaks of soot around your furnace or supply registers, or you may notice excessive rusting on the flue piping coming from the heating system, or even water leaking from the base of the chimney, vent, or flue pipe.
Always be mindful and monitor your furnace for any of the signs noted above and always make sure you have working carbon monoxide detectors on every floor of your home, particularly close to your furnace room.
As furnaces age, they run the risk of developing cracks in the heat exchanger, causing carbon monoxide to leak into your home undetected. Signs of this may be frequent headaches, a burning feeling in nose or eyes, nausea, disorientation, flu-like symptoms. If you or your family are experiencing symptoms like this, you should immediately open your windows and place an emergency service call to your heating professional.
Old furnaces will sometimes make strange noises as they get toward the end of their life. Have you heard any banging, popping, rattling, or squealing noises coming from your furnace? Is your furnace blower running excessively? Does your blower turn on and off frequently or does it blow cold air sometimes? If so, these are all signs that your furnace may need to be replaced.
If your heating system is about 18 to 20 years old, I would suggest you call your heating professional to have them fully inspect your heating system to ensure it's safe operation. Compare your energy bills over the last 3 years and see if there has been an increase of usage over time. If your heating system is running inefficiently, you are spending more money than you should on energy costs and can use those dollars on purchasing a new, more efficient system.
A good rule of thumb is, if the cost of the repair is 50% of the cost of a new heating system, you should replace it. An exception to that rule would be if your heating system is older than 20 years, the cost of the repair should be less than 15% of the replacement cost, to warrant the repair. Chances are a heating system more than 20 years old will continuously need repairs as the years go by. As each repair is made, the cost of maintaining your older, less efficient heating system becomes less warranted.
If you think you need a new heating system, consult a professional. Newer systems can provide you with a substantial energy savings and provide you with more comfort in your home. The newer technology of the heating systems on the market today are designed to provide more even heating, at a lower cost of operation, and with more versatility in operation. Couple that with a thermostat which uses the latest technology, the savings can be even greater.
Jim Hall, President – Jim Hall Heating & Air Conditioning 718-948-2456www.jimhallhvac.com