Furnace problems only become more expensive over time. Staying on top of maintenance can help you find problems sooner. If you are aware of any of these signs of trouble with your furnace, promptly schedule a repair:
You should plan on replacing your furnace as it starts to get old. An outdated furnace can struggle to adequately heat your home. High energy bills and a cracked heat exchanger are signs you should replace an old furnace.
A heat exchanger is an expensive part to replace. Old furnaces naturally lose efficiency, so there is only so much an HVAC technician can do to make an old system run more efficiently. A general rule of thumb is to never repair something when the repair costs are more than one-third the cost of a replacement. If your old furnace has needed repairs more than two times in the past two years, it's time to replace it.
Dirty air filters and internal components are often the culprits. This is why it's important to keep up with maintenance. A technician will clean your furnace's internal components during a tune-up.
If your furnace isn't old, inefficient heating is a problem you can probably fix with a repair or a tune-up. Dirty air filters restrict airflow in the furnace, so they can result in inefficient heating. Thermostat problems can also cause your furnace to fail. Your furnace may heat unevenly, fail to reach the set temperature, or fail to turn on at all. Try changing the batteries. If that doesn't work, an expert HVAC technician can diagnose your system for you.
Short cycling occurs when your furnace turns on and off too frequently. An oversized furnace can cause short cycling. After giving a blast of warm air in your house, the system will shut off because its sensors detect the warm air. If you notice short cycling on a furnace that wasn’t recently installed, there’s likely a different cause. Short cycling also shortens the lifespan of your heating system, so you should have an expert technician service it.
When your furnace makes unusual noises — squealing, rattling, banging and screeching — it's in need of repair or maintenance. One of many problems may be the cause behind an unusual sound from your furnace, but only an expert repair technician can diagnose it.
Parts inside the system may have loosened or broken. Squealing sounds usually mean that moving parts in the system have lost lubrication. During a maintenance call, expert furnace technicians lubricate these moving parts to prevent this problem.
If you smell gas, turn off the furnace immediately. It’s best to leave your home until a technician has confirmed it's safe for you to return. Bring any pets with you too. Gas leaks are a safety risk.
A burning plastic odor or metallic smell can signal a wiring problem. You may have wires melting, which is a fire hazard. Turn your furnace off until it can be replaced.
Routine maintenance reduces the chance you'll have gas leaks or electrical problems with your furnace. Expert maintenance technicians thoroughly inspect your furnace to catch early signs of deterioration.
If you smell something burning when you have just turned on your furnace, it’s probably dust. Dust accumulates in your system while it’s not in use. When you turn your furnace on for the first time, that dust may burn. This isn’t usually a concern.
Musty odors are usually caused by mold. You should have an expert technician investigate the source of the musty smell since mold is harmful to your health.