How long does an HVAC system last?

Most heating and cooling equipment lasts somewhere between 10 and 20 years, with gas furnaces usually outlasting air conditioners and heat pumps. There is no single number, and the manufacturers themselves do not agree on one. What they do agree on is that how the system was installed, how it is maintained and how hard it works each year decide whether yours reaches the short or the long end of the range.

What the manufacturers say

Estimates from three major brands:

• Trane says an air conditioner or heat pump has a service life expectancy of 10 to 12 years and a furnace 15 to 20 years.^[1]
• Lennox puts air-source heat pumps at 10 to 15 years, central air conditioners at 12 to 15 and standard furnaces at 15 to 20.^[2] Lennox puts electric furnaces at 20 to 30 years and boilers at 15 to 30.^[3]
• Carrier's current residential guidance gives furnaces and air conditioners 15 to 20 years and heat pumps 10 to 15.^[4]

Lennox adds that ground-source heat pumps can sometimes last 20 to 25 years, because they work with steadier underground temperatures.^[2]

Heat pumps tend to sit at the shorter end for a simple reason. In Carrier's words, heat pumps run year-round to provide both heating and cooling, resulting in more operational wear than a furnace that only runs during colder months.^[4] If a heat pump both heats and cools your house, plan for the shorter end of the range.

When age starts to matter

Age alone is not a reason to replace a working system, but it is a reason to start planning. ENERGY STAR suggests considering replacement when a heat pump or air conditioner is more than 10 years old or a furnace or boiler is more than 15.^[5] Its other signs are equipment that needs frequent repairs while energy bills climb, and rooms that are too hot or too cold.^[5] Replacing on your own schedule leaves time to compare quotes, instead of taking whatever is in stock during a breakdown.

What shortens a system's life

Installation and sizing. The clock starts on installation day. ENERGY STAR puts it directly: "Oversized equipment may cycle too frequently, resulting in less comfort and a shortened lifespan."^[6] It adds that poor airflow can also shorten equipment life.^[6] Lennox makes the same point about furnaces from the other side: a larger-than-needed one runs short cycles, while a smaller-than-necessary furnace runs long cycles as it struggles to reach the setting, and both add wear.^[3] This is why a load calculation matters when you buy, as covered in what installing a new HVAC system involves.

Skipped maintenance. ENERGY STAR's checklist explains what a yearly visit protects. Dirty coils make the system run longer, raising energy costs and reducing the life of the equipment,^[7] and too much or too little refrigerant has the same effect.^[7] Faulty electrical connections can cause unsafe operation and reduce the life of major components.^[7]

Neglected filters. ENERGY STAR recommends inspecting, cleaning or changing the filter once a month, since a dirty filter can damage the equipment and lead to early failure.^[7] See how often to change a furnace filter.

The outdoor unit's surroundings. Virginia Cooperative Extension adds a detail many people miss: do not vent a clothes dryer within 10 feet of the outdoor unit, because lint clings to the coil and lowers both its efficiency and service life.^[8] Keeping leaves, grass clippings and shrubs clear of the coil helps for the same reason.

Keeping a system going longer

The habits that help most are simple and cheap:

• A licensed contractor's check-up every year. ENERGY STAR recommends a contractor check-up every year before each season: the cooling system in spring and the heating system in fall.^[7] For what to expect, see how often an air conditioner should be serviced and what an HVAC tune-up costs in Virginia.
• A clean filter, inspected, cleaned or changed once a month as ENERGY STAR recommends.^[7]
• A clear outdoor unit, with plants trimmed back and nothing stored against it.
• Fixing small problems early, such as a refrigerant leak, rather than living with them.

Older refrigerant and the repair-or-replace decision

Some air conditioners still in use run on HCFC-22, often called R-22, a refrigerant the United States is phasing out, and a new central AC unit that uses it can no longer be bought.^[9] EPA does not require homeowners to replace existing R-22 equipment,^[9] but no new R-22 has been made or imported into the United States since January 1, 2020,^[9] though EPA says used R-22 that is cleaned up to the same specifications as new refrigerant will continue to be available.^[9] If it leaks, EPA's advice is to ask the technician to find and repair leaks rather than "topping off" the system.^[9]

For the repair-or-replace call, two rules of thumb are common. Carrier suggests weighing replacement when a repair approaches 50% of the value of a new system.^[4] Trane describes a "$5,000 rule"^[1]: multiply the equipment's age by the repair estimate, and if the result is over $5,000 a new system probably makes more financial sense. Its example is a 10-year-old system needing a $600 repair, which comes to $6,000.^[1] Check your warranty first: Trane notes that warranties from most manufacturers run from five to 10 or 20 years depending on the unit, whether it was registered and whether you are the original owner or it transferred with the sale of the home.^[1] When replacement does make sense, how much a new HVAC system costs in Virginia explains the price.

When to call a licensed pro

For the yearly check-up and anything beyond the filter. Under Virginia law, an individual who does heating, ventilation and air conditioning work for the general public for compensation is a tradesman,^[10] and must be licensed, or work under the supervision of a tradesman licensed in that specialty.^[11] Call sooner when the system needs repairs more than once a season, bills rise without explanation, rooms stop heating or cooling evenly, or you notice what Carrier calls grinding sounds or persistent odors.^[4]

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