4 Signs It’s Time to Replace and Aging HVAC Unit

Nobody likes to think about having their air conditioner or furnace break down, but it is something that will almost certainly happen eventually. Some aging HVAC units can be repaired, but at some point it will just make more sense to buy a replacement. Fortunately, it isn’t all that difficult to know when an HVAC unit needs to be replaced. All it takes is to pay attention to certain telltale signs.

The Age of the Unit

According to this infographic from Washington Energy Services, an HVAC unit will last between 12 and 20 years, with air conditioners lasting longer since they don’t get as much use. As a rule, any unit that is at least 10 years old can probably stand to be replaced, but units that have been receiving the proper maintenance can still run efficiently with some minor repairs.

For those who don’t know whether to have an HVAC unit repaired or replaced, according to Brad Wentz of Buckeye Heating & Cooling, a good measure is to take the age of the equipment and multiply that by the repair cost. Wentz also explains that if the number is more than $5,000, then it’s time to consider a replacement. For example, a 10-year-old unit with a $350 repair equals $3,500. It’s OK to repair. Wentz calls this the $5,000 rule, and it works well for any HVAC unit.

Higher Heating Bills

According to the Energy Star website, a higher heating bill is a good indicator of an aging HVAC unit that needs to be replaced. Furnaces and air conditioners become less efficient as they get older. That causes them to work harder to maintain a consistent temperature, which leads to higher energy bills.

Higher energy bills may only mean that a unit’s air filter needs to be replaced or that a home’s duct work needs to be cleaned. When they are combined with a unit that is over a decade old, a replacement may be in order.

A Noisy Unit

When an HVAC system is fairly new and running smoothly, it is almost silent. Homeowners may hear a faint hum or rush of air when it is turned on, but that is easily ignored. On the other hand, a unit that is on its last legs will make rattling or knocking sounds when it used and especially when it is first turned on. This is sometimes an indicator that repairs need to be made, but homeowners should consider a replacement when these sounds are heard in an older unit.

Strange Smells

A poorly-functioning furnace that is on its last legs may send strange smells throughout a home. This will smell like something is burning or like exhaust fumes. Not only is this inconvenient, but it can also be dangerous. A malfunctioning furnace can increase the levels of carbon monoxide in the home, sometimes to deadly levels. A burning smell coming from a furnace that is turned on needs immediate attention. As always, a newer furnace may be repaired, but an older unit may need to be replaced instead.


No Programmable Thermostat

A programmable thermostat won’t automatically translate into lower heating bills, but it does make managing a home’s temperature much easier. Most modern HVAC units come with programmable thermostats, so the distinct lack of one is an indicator that a home needs a new furnace or air conditioner, one that is much more energy-efficient.