The contractor has found the problem, and now there is a choice: fix it, or start again with a new system.
Online you will find rules of thumb built on the age of the unit and the price of the repair. This article uses none of them. Every system and every house is different, and the clearer answer comes from asking the right questions about yours. Take these lists with you when the contractor visits, and ask for the answers in writing.
Questions about the repair
- What exactly has failed, and why?
- What will the repair cost, in writing?
- Is this part likely to be the start of more repairs, or a one-off?
- Has anything else on the system been flagged at a check-up?
- Will the system cool the house properly once it is fixed, or was it struggling before?
A repair to a small part on a system that otherwise cools the house well is usually an easy yes. A repair to a major part on a system that has needed several fixes is where the replacement question starts.
Questions about a replacement
- What would you install instead, and how did you size it?
- Which refrigerant does it use?
- Would a heat pump make sense, if the furnace is old too?
- Do the ducts need work for the new system?
- Who pulls the permit, and who arranges the ECC testing?
- What is the price, in writing, and what is the payment schedule?
What has changed in new systems
One reason the answer can lean toward replacement is the refrigerant. Under federal rules that began in 2025, newer systems use newer refrigerants. Under the EPA’s Technology Transitions Program, beginning January 1, 2025, manufacturers and importers of certain products and equipment that use HFCs must comply with restrictions on the use of certain HFCs, and new air conditioning and heat pump products carry labeling. Ask the contractor what that means for servicing your current system in the future, and which refrigerant a new one would use.
What a replacement involves
A replacement is permitted work. The City of San Diego requires a mechanical permit for HVAC systems that are installed, altered, replaced or repaired, and CHEERS, a California Energy Code registry, says HVAC replacements must be permitted at the local building department and tested and verified by an independent ECC rater. Because the job needs a permit, anyone you hire for it needs a contractor’s license: the CSLB class is C-20, and you can look up any license on cslb.ca.gov. The AC replacement guide covers the job step by step.
Comparing the two prices
Ask for the repair price and the replacement price side by side, both in writing. For a decision this size, get more than one opinion: another contractor may see the same system differently. If you choose to replace, CSLB cautions that a down payment should not exceed 10 percent of the contract price, and later payments should not run ahead of the work done or materials delivered. Ask the contractor and SDG&E about current rebates or incentives before you decide.
Questions about the house
Sometimes the system is fine and the house has changed around it. An addition, a converted garage or a new home office can leave the old system short. Ask whether the trouble is the equipment, the ducts or the size of the space it now has to cool. If one room is the problem, a ductless head for that room may be an alternative to replacing the whole system; see mini split installation.
If you repair for now
Keep up the monthly filter check and the yearly check-up ENERGY STAR recommends, and keep a record of what has been fixed. If the same question comes back, you will have the history to hand. The AC maintenance guide covers what to do in between.
Air Conditioning Repair San Diego is an independent referral service, not an air conditioning or HVAC company. Calls and form requests are passed to an independent local AC and HVAC contractor, who can contact you about your system; that contractor gives any quote and does any work.
Want a second opinion on repair or replace? Call the number on this page or send the form, and an independent local AC contractor can contact you.
Questions people ask
How often do I need to replace my AC unit?
There is no fixed schedule. Consider replacing it when repairs keep coming, a major part fails, or the system cannot cool the house. Ask the contractor for both prices.
Is it worth repairing an old AC?
It can be, for a small part on a system that otherwise works well. Weigh it against the replacement price and the refrigerant question.
Does replacing an AC need a permit?
Yes. In the City of San Diego a mechanical permit is required, and replacements need independent ECC testing under the Energy Code.
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