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How long does AC installation take?
The work on site for a straightforward replacement on existing ducts is usually a day or two; new ducts, a panel upgrade or a multi-zone mini-split add days. Around that, quotes, the permit, equipment, the rater's visit and the final inspection set the full timeline.
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- Two clocks, not one
- Key takeaways
- What sets the time on site
- What adds time around the install
- The season matters in LA
- If your AC has already failed
- How to keep it short
- A typical project timeline
- Put the schedule in the contract
- Common causes of delay
- How the timeline differs by system
- Express permit or plan check?
- If it is 100 °F and the AC just died
- For landlords and property managers
- Condos and HOAs
Two clocks, not one
"How long does it take?" has two answers. The crew's time at your house is short. The time from your first call to a closed permit is longer, and it is the one that matters if your AC died in August.
On-site work
Usually a day or two for a like-for-like replacement on usable ducts. Longer for ducts, panels and multi-zone systems.
Whole project
Quotes, permit, equipment, install, rater visit and final inspection. Each step waits on someone's calendar.
On-site durations here are typical of the trade, not a measured LA figure. Ask each contractor for a written schedule.
Key takeaways
In short
- On-site work for a simple replacement: usually a day or two.
- Ducts, panels and multi-zone systems add days.
- Quotes, the permit, the rater and the inspection set the full timeline.
- Spring and fall move fastest in the Valley.
What sets the time on site
| Job | Relative time on site | What adds time |
|---|---|---|
| Like-for-like AC change-out, usable ducts | Shortest | Hard attic access, a stuck old line set |
| Heat pump replacing AC and furnace | Longer | Electrical work, capping the gas line |
| New or replaced ducts | Several days | Attic or crawlspace work, asbestos found |
| Single-zone mini-split | Short | Wall penetration, line-set route |
| Multi-zone mini-split | Longer per head | Each head needs a line set and drain |
| Panel upgrade | Separate appointment | Utility disconnect and reconnect |
| Rooftop unit | Separate appointment | Crane booking |
What adds time around the install
- Quotes. Two or three home visits, then written quotes. Compare them in the quote tool.
- Permit. In the City of Los Angeles the permit comes from LADBS. A same-location change-out at similar capacity and the same fuel, reusing the ducts, is sold as an online express permit with no plan check; a heat pump that adds a circuit also needs an electrical permit. Other cities have their own process; see the permit guide.
- Equipment. Stock of the specific model and refrigerant.
- Install day or days.
- Rater visit. Booked after installation.
- Final inspection. Booked with the building office.
An express permit is fast, a plan check is not
In the City of Los Angeles a like-for-like change-out is sold as an online express permit (verify with LADBS). Jobs that change fuel, add capacity or move equipment may not qualify, and those take longer. Ask the contractor which kind your job needs.
The season matters in LA
In the Valley, the first heat wave fills contractors' calendars. A replacement planned in spring or fall usually moves faster, and gives you time to compare quotes and check rebates.
If your AC has already failed
- Ask whether the contractor can install a temporary portable unit or prioritize a like-for-like swap.
- Do not skip the permit to save days: LADWP's heat pump rebate needs the final approved permit, and an unpermitted job can surface when you sell.
- Keep comparing: one quote in a heat wave is often the most expensive one.
How to keep it short
Six things that save days
- Get quotes in spring, before the Valley heat arrives.
- Have the old unit's model plate photographed.
- Have panel details and attic access ready (preparation checklist).
- Get HOA approval for any new outdoor-unit spot first.
- Agree in writing who books the rater and the inspection.
- Choose equipment the contractor has in stock.
A typical project timeline
| Stage | Waits on | What speeds it up |
|---|---|---|
| Home visits and quotes | Contractor calendars | Call several at once, in spring |
| Choosing and signing | You | Use the quote tool to compare fast |
| Permit | The building office | Express permit for a like-for-like job |
| Equipment | Distributor stock | Choose a model in stock |
| Installation | The crew | Clear access, approvals in hand |
| Rater visit | The rater's calendar | Contractor books it ahead |
| Final inspection | The building office | Be available for access |
Put the schedule in the contract
- Start date and expected days on site.
- Who books the rater and the inspection, and roughly when.
- What happens if the ducts fail the test.
- Payment schedule tied to the work: CSLB cautions that a down payment should not exceed 10 percent and later payments should not run ahead of the work.
CSLB press release #24-21.
Common causes of delay
| Delay | Why | Prevent it |
|---|---|---|
| Ducts fail the leakage test | Sealing and retest needed | Ask for a duct check at the quote |
| Panel too small | Upgrade and utility appointment | Send a photo of the panel label early |
| HOA objection | Outdoor spot not approved | Get written approval before signing |
| Asbestos found | Abatement comes first | Ask about old duct wrap at the visit |
| Wrong equipment delivered | Model mismatch | Check model numbers on the quote |
How the timeline differs by system
Heat pump
- Electrical work, sometimes a panel upgrade with a utility appointment.
- Gas line capped if the furnace goes.
- Rebate paperwork after the final permit.
Mini-split
- Short per head; longer for several heads.
- HOA approval often the longest wait in condos.
- No duct test, so no duct-fix delay.
Express permit or plan check?
| Job | Likely permit path in the City of LA | Effect on timeline |
|---|---|---|
| Same location, similar capacity, same fuel, ducts reused | Online express permit (verify with LADBS) | Short |
| Heat pump adding a circuit | Express mechanical plus an electrical permit (verify) | Short to moderate |
| Equipment moved, fuel changed or new ducts | Ask LADBS; may need more review | Longer |
| Outside the City of LA | Your own city or LA County | Varies |
LADBS, "Mechanical HVAC Permits" and Express Permits bulletin P/GI 2020-003 (LADBS refused our automated read); marked verify.
If it is 100 °F and the AC just died
A short plan
- Call two or three contractors the same morning.
- Ask each whether they have a like-for-like unit in stock.
- Ask for a written quote even if they can start tomorrow.
- Keep the permit in the job.
- Use fans and close blinds on the sunny side meanwhile.
For landlords and property managers
In occupied rentals, the schedule has to include tenant notice and access for each visit: the quote, the install, the rater and the inspector. Ask the contractor to book the rater and inspection with your access windows in mind, and keep the finalled permit with the unit's records.
Multi-unit buildings: see AC installation for multifamily buildings.
Condos and HOAs
In condos, the longest wait is often the HOA, not the contractor. Get the outdoor-unit location, any wall penetration and the work hours approved in writing before you sign. Some buildings also require the contractor's insurance certificate before work starts. See AC installation for condos.
Sources
- LADBS, "Mechanical HVAC Permits" and Express Permits bulletin P/GI 2020-003 (LADBS refused our automated read) (retrieved 2026-09-29) — verify before relying on it
- California Energy Commission, "Building Energy Efficiency Resources for Single Family Homes" (retrieved 2026-09-29)
- California Energy Commission, "Home Energy Rating System (HERS) Program" (retrieved 2026-09-29)
- NOAA NCEI, U.S. Climate Normals 1991–2020, annual/seasonal (stations USW00023174, USW00093134, USW00023152, USC00049785) (retrieved 2026-09-29)
- LADWP, "Consumer Rebate Program" (retrieved 2026-10-20)
Questions
How long does it take to replace a central AC?
On site, a like-for-like replacement on usable ducts is usually a day or two. The rater visit and final inspection come afterwards, on separate days.
How long does a mini-split installation take?
A single head is usually a short job. Each extra head adds a wall penetration, line set and drain, so multi-zone systems take longer. Ask for a written schedule.
How long does a heat pump installation take?
Longer than a straight AC swap when it replaces a furnace, because of electrical work and capping the gas line. A panel upgrade is often a separate appointment.
How long does an AC permit take in Los Angeles?
In the City of Los Angeles a like-for-like change-out is sold as an online express permit with no plan check (verify with LADBS). Other cities and bigger changes vary; ask your city's building office.
How long does new ductwork add?
Several days on site, typically, depending on attic or crawlspace access and how much duct is replaced. Asbestos found on old ducts adds more, because abatement comes first.
Can AC be installed in one day?
Often, for a like-for-like change-out on usable ducts with good access. The permit closes later, after the rater and inspector visits.
Why is the rater visit separate?
Because the Title 24 tests are done by a third-party rater, not the installer. Since 1 January 2026 they work under the CEC's ECC program.
What is the fastest way to get AC installed in a heat wave?
Choose equipment in stock, keep the job like-for-like, have access and panel details ready, and keep the permit. Skipping the permit costs more later.
Does a panel upgrade delay the install?
It can. A panel upgrade often needs a utility disconnect and reconnect appointment, so it may be scheduled separately from the AC work.
How long until I can apply for a rebate?
After the final inspection. LADWP's heat pump rebate application needs the final approved permit, so the rebate comes at the end of the timeline.
Next step
Free quote request
Get a quote to check against these numbers
- Tell us about the job. Service, ZIP, property and timing. The form says right away if your ZIP is outside the area.
- We check the license first. Requests go only to contractors whose CSLB C-20 license we have matched on the state register. If none covers your ZIP yet, we email you and say so.
- Compare what comes back. Line the written quote up against the published ranges and the quote checklist.
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