How long does an HVAC system last
A gas furnace lasts 15 to 25 years and an air conditioner 15 to 20. Those ranges are wide on purpose: two identical systems on the same street routinely differ by a decade, and almost none of it is brand.
National average
$11,000
per project
On this page
- What lasts how long
- What actually decides it
- The signs it is near the end
- Planning beats an emergency
- Frequently asked questions
- Does brand affect how long it lasts?
- Should I replace a system that still works?
- Does running it constantly wear it out faster?
- How much does maintenance actually extend life?
- My system is 22 years old and works fine. Am I overdue?
A gas furnace lasts fifteen to twenty-five years. An air conditioner or heat pump lasts fifteen to twenty. Ductwork lasts as long as the house if it was sealed properly and nobody stood on it.
Those are wide ranges on purpose. Two identical systems installed on the same street in the same year routinely differ by a decade, and almost none of that difference is brand.
What lasts how long
| Component | Typical life |
|---|---|
| Gas furnace | 15 to 25 years |
| Air conditioner, central | 15 to 20 years |
| Heat pump, air source | 12 to 18 years |
| Heat pump, geothermal, indoor unit | 20 to 25 years |
| Geothermal ground loop | 50 years or more |
| Mini split | 12 to 20 years |
| Boiler, cast iron | 20 to 30 years |
| Boiler, condensing | 15 to 20 years |
| Evaporator coil | 10 to 20 years |
| Compressor | 10 to 20 years |
| Blower motor | 10 to 20 years |
| Ductwork, sheet metal | 30 to 50 years |
| Flexible duct | 15 to 25 years |
| Thermostat | 10 to 15 years |
An air source heat pump sits below an air conditioner because it runs year round and accumulates roughly twice the hours.
What actually decides it
Installation quality. The single biggest factor and the one nobody can see. A system charged by weight, with a vacuum pulled, on correctly sized ductwork, with the airflow measured, will outlast an identical system installed carelessly by years. This is why the contractor matters more than the brand.
Sizing. An oversized system short cycles: it cools quickly, shuts off, and starts again. Compressor starts are what wear compressors, and a system that starts three times an hour instead of once ages three times as fast.
Maintenance. Mostly the filter and the condenser coil. Restricted airflow makes every motor run hot, and heat is what ends motors. This is also where the warranty lives: most manufacturers require documented annual service.
Climate and runtime. A system in Phoenix runs perhaps 2,000 cooling hours a year; one in Portland runs 400. Coastal salt air attacks outdoor coils and can take five years off a condenser.
Refrigerant charge. A slow leak starves the compressor of the oil that circulates with the refrigerant. Repeated top-ups without finding the leak is the most reliable way to kill a compressor early.
The signs it is near the end
None of these mean replace tomorrow. Together they mean start planning.
- Rising electricity bills with no change in weather or occupancy
- Rooms that never used to be uneven now being uneven
- Running much longer to reach the same setpoint
- A second significant repair within two seasons
- R-22 refrigerant, which puts the system at fifteen years minimum and makes any leak expensive
- Noise that is new: grinding, screeching, or a bang on start-up
- Humidity that is no longer being removed in summer, which is a system losing capacity
Planning beats an emergency
The most expensive HVAC purchase is the one made on the hottest day of August with no cooling in the house. You take what is in the warehouse, at the price offered, from whoever can come.
If your system is past twelve years and showing two or three of the signs above:
- Get a quote in the shoulder season, spring or autumn, when contractors are not busy. The same job is frequently several hundred dollars cheaper.
- Check what incentives are current. The federal credit returns up to $2,000 on a qualifying heat pump and up to $600 on a qualifying furnace or air conditioner, and utilities often add rebates.
- Decide in advance what you would buy, so the decision is not made in a crisis.
- Ask for a load calculation with the quote rather than a tonnage guess.
Frequently asked questions
Does brand affect how long it lasts?
Far less than people expect. The compressors in most residential equipment come from a small number of manufacturers, and the same brand appears at the top and bottom of reliability comparisons depending on the installer. Choose the contractor.
Should I replace a system that still works?
Only if the arithmetic works. A functioning fifteen year old system in a mild climate owes you nothing, and replacing it to save $150 a year does not pay back. In a hot climate where an old system costs $500 a year more to run, and with a $2,000 credit available, it can.
Does running it constantly wear it out faster?
Continuous running at low speed is easier on equipment than frequent starting is. That is most of the argument for variable-speed systems. What wears things is starting, and short cycling from an oversized system is the common cause.
How much does maintenance actually extend life?
Realistically a few years, and more importantly it keeps the parts warranty valid. The efficiency claims are overstated; the warranty and the caught-early capacitor are the real value.
My system is 22 years old and works fine. Am I overdue?
You are past the average and you have a well-installed, well-maintained system, which is exactly the population that lasts. Keep servicing it, plan the replacement rather than waiting for it, and check the refrigerant type so you know what a leak would mean.
Read next
Repair or replace your HVAC system$6,500 to $22,000per projectThe $5,000 rule says multiply the repair by the age of the system and replace above $5,000. It is memorable and it is wrong often enough to cost money. Here is the arithmetic that works, and the cases where it is not close.
HVAC tune-up cost$85 to $250per eachA tune-up costs $85 to $250 a visit. It is the cheapest thing you will spend on the system and the one most often sold as something it is not. A real service is an hour of measurement; a $59 special is twenty minutes and a sales conversation.
HVAC cost by house size$6,500 to $20,000per projectA full changeout runs about $9,600 in a 1,100 square foot house and about $12,400 in a 2,800 square foot one. The house more than doubles; the bill goes up by less than a third, because most of what you pay for is the crew and the day.
Ductwork replacement cost$3,500 to $12,000per projectReplacing ductwork costs $10 to $35 per linear foot, and a typical house carries 150 to 350 feet. Sealing sound ducts costs far less and often recovers most of the lost airflow.
How to pay for an HVAC system$6,500 to $22,000per projectAn $11,000 replacement usually arrives on the day the system stops, and that timing is what makes the financing expensive. Incentives first, then a home equity line, then a credit union. The spread across that list is thousands.