How Long Should A Furnace Last?
Your home furnace should last more than 20 years, but many fail to even make it to the 10 year mark before suffering serious damage. Some of the reasons for premature furnace failure are the following:
Your furnace doesn’t have an expiration date and it is quite common for us to repair furnaces that are more than 50 years old. Sure they use a lot of natural gas, those older furnaces are still functioning. They are still repairable and as long the homeowner knows all the options for repair or replacement they can make an informed intelligent decision regarding their fate of their own furnace.
You are the only one that decides whether to replace your furnace or not
If you are told that the parts for your older furnace are no longer manufactured you are probably being told the truth, but not the whole truth. The only part of your older furnace that cannot be repaired or replaced is the firebox or heat exchanger. Every other part is easily substituted for more modern reliable and safe parts. If your furnace is not cracked it can be fixed and most likely can be fixed with the common parts that we stock on each of our service trucks.
The number one reason for furnace failure is lack of furnace maintenance. Your home heating system is susceptible to dirt. It builds up on the blower wheel and the blower motor and can clog evaporator coils. This buildup of debris slows the amount of traveling over the heat exchanger and this causes the heat exchanger to run at elevated temperatures which leads to cracks forming. Clean is good, dirty is bad.
Furnace maintenance is not changing a filter or calling the local carpet cleaner to clean your ducts for $50. Every single company that advertises duct cleaning below $150 has based their business model on fraud. It cannot be done and make any money at all so they are just trying to get in the door and hit you up for extra after extra. A handyman cannot service your furnace. They are not trained and do not have the proper tools to analyze the combustion air, carbon monoxide output, air speed and air volume. Ask one of them if they have a Bolometer, a flow hood or if they can traverse a duct. A Bolometer and a flow hood are measuring devices for volumes of air. Traversing a duct involves taking air speed readings at critical points across the face of the duct and then calculating out the air flow. If you don’t know how much air is being moved you don’t how well the system is working. Without this knowledge a furnace maintenance can turn into premature furnace failure.
Nearly all furnace installations here in Southern California are too big for the homes. It is because we live in an environment more concerned with air conditioning. Real problems can occur when someone install a furnace that is too big because the heat exchanger will heat up more than its design temperature and the furnace will short cycling. Heating up the home quickly and then having the furnace turn off only to have it turn back on a few minutes later is likely driving in rush hour on the 405 freeway and at each stop turning the engine off to only restart it again. This short cycling will kill a furnace.
We all ignore it and a dirty air filter chokes off the air supply to the furnace creating a hotter than normal environment which shortens the lifespan of the heat exchanger.
You will not save any money (pennies only) closing supply registers to rooms that you don’t use. The walls between the rooms in your home are not insulated. Very little air is redirected by closing off the registers. This is because the fan blade than your furnace operates at cannot push a lot of pressure. Most home furnaces are designed to operate at 0.5 inches of water column. This means that the pressure they push is designed to b able to push water up a column of air only ½ of an inch. More pressure than that decreases the amount of air flow and can cause over heating of the furnace.
Common cleaning chemicals found in the laundry room when mixed with air, natural gas and heat can cause a caustic reaction and prematurely rust a firebox. If your furnace is located next to your washing machine you should, when the time comes, switch it out to a closed combustion chambered furnace that pulls the air it burners from outside the home.
If the cap on the roof collapses or the inner liner to the furnaces dual venting system is damaged the obstruction of flue gases can cause the furnace to overheat causing damage.
This is second most common reason for premature furnace failure. Ducts too small, too long and the return air cavity obstructed or too small can choke a furnace to death. The condensation line from the evaporator coil running uphill can cause water to dump on and into the furnace burning out electrical controls and rusting the furnace over the years.
This is so critical that the manufacturers of furnaces no longer offer any warranty or guarantee to any furnace purchased on line. It is hard enough to get contractors to do good quality work. Furnace installations are not for the untrained. Always demand a permit and city inspection. It will protect you from most poor quality craftsmanship.
The biggest furnace recall, Consolidated Industries-Premier Furnace, was caused by poor quality metal, over fired burners and a blower motor that didn’t put out as much air as the manufacturer stated. Many furnaces on the market are not designed very well and these design deficiencies make for more service work. Not all furnaces are created equal.