HVAC
How do I know if my HVAC system needs to be replaced?
Updated October 21, 2026
Weigh its age, repair history and energy bills together, because age alone doesn't necessarily mean you need a whole new system.
Do this now
- Note the age of your AC, heat pump or furnace.
- Pull out your energy bills from the past two years.
- Change the furnace filter if it's been two months.
Common causes
| Cause | Signs | Fix |
|---|---|---|
| Aging AC or heat pump | Your air conditioner or heat pump is more than 10 years old. | Ask a pro whether it's worth repairing or replacing. Find a pro |
| Aging furnace or boiler | Your furnace or boiler is more than 15 years old. | Ask a pro how much useful life it has left. Find a pro |
| Worn, less efficient equipment | You call for repairs often, and your heating and cooling bills keep going up. | Show a pro your list of repairs and recent bills. Find a pro |
| Duct, insulation or operation problem | Some rooms in your home are too hot or too cold. | Have a pro check the ducts and insulation. Find a pro |
| Leaky ducts | Dust spreads through the house, since leaky ducts can pull it from the attic, crawl space or basement. | Ask a pro to test the ducts for leaks. Find a pro |
Check your system before you find a pro
Check the signs
- Set this year's heating and cooling bills beside last year's, month by month, and spot jumps.
- Count the repair visits you've paid for in the last few years, and note what failed.
- Walk each room while the system runs and note any that feel off from the rest.
Keep it running
- Swap the furnace filter at least every other month, since fresh filters help the system last.
- Book routine maintenance, the most effective way to stretch the life of your HVAC system.
Get ready for the pro
- Write down each unit's age, your bill changes and your problem rooms to show the pro.
Common questions
How long do furnaces and AC units last?
Furnaces may last 15 to 30 years, while AC units and heat pumps typically last 15 to 20. Over 15 years, it may be time to check a system's condition.
Will a new system lower my energy bills?
High-efficiency AC units and heat pumps, installed correctly, can save up to 20 percent on heating and cooling. An efficiency-qualified furnace is 15 percent more efficient than a conventional one.
When does repairing stop making sense?
If you're constantly paying for HVAC repairs, those costs may soon outweigh the price of a new, reliable heating or cooling unit.
Can I just replace a bad blower motor?
A furnace's age is a key factor in choosing between a new blower motor and a new furnace. Under 10 years old, the motor alone may be the best choice.
What happens to a furnace as it ages?
As furnaces get closer to 15 years old, they start to become less efficient and see more wear and tear.
Want a pro to handle it? Find background-checked HVAC pros on Traeos.