Last updated October 8, 2026
Seasonal tune-up and full diagnostic on your Carrier, Trane, or Goodman system - readings shown to you before any repair is proposed
Diagnosis first, numbers second - you approve the repair price before a single part goes in.
Before
After
Before
After
Before
AfterHow Long Does AC Installation Take? Timelines and What to Expect
Most homeowners in Los Angeles assume the clock starts when the crew arrives and ends when the truck pulls away. In our experience, that’s rarely where delays actually happen. The installation itself is rarely the bottleneck - it’s the electrical panel, the ductwork condition, and the permit inspection schedule that determine whether your new system is running in one day or one week. This guide breaks down honest timelines for the four most common AC Installation services scenarios we see across Los Angeles, explains the hidden variables that extend schedules, and shows you exactly what questions to ask before you sign so you’re never surprised.
Quick Answer
A straightforward AC installation in Los Angeles takes four to eight hours in a single day. Most replacement jobs - where we’re swapping an old unit for a new one using existing ducts and electrical - are finished before dinner. Projects stretch to two days or longer when they require electrical panel upgrades, new ductwork runs, or scheduled LADBS inspections that can’t be completed same-day - read our guide on How Long Does AC Repair Take? Timelines and What to Expect for related timing insights.
Table of Contents
- AC Installation Timelines by Scenario
- LADBS Permits and Inspections: The Real Schedule Driver
- Electrical Panel Upgrades in Older Los Angeles Homes
- What Happens on Installation Day: Hour by Hour
- Questions to Ask Before You Sign
- Common Mistakes to Avoid
- When to Call a Professional
- Frequently Asked Questions
AC Installation Timelines by Scenario
Not every “AC installation” is the same job. We’ve replaced systems in Mid-Century bungalows in the Valley and installed ductless mini-splits in hillside additions in Silver Lake, and the work looks completely different. Here are the four scenarios we quote most often in Los Angeles, with realistic timeframes.
Scenario 1: Replace-in-Kind Swap (4-6 Hours)
This is the simplest job. We’re removing an existing split system and installing a new condenser (the outdoor unit) and evaporator coil (the indoor piece that sits above your furnace or air handler), using the same refrigerant lines, electrical disconnect, and duct connections. In Los Angeles, these jobs are common in homes built from the 1970s through the 1990s where the original system has simply reached end of life.
What makes it fast: no new electrical circuits, no duct modifications, no line-set rerouting. We disconnect, remove, set the new equipment, pressure-test the lines, pull a vacuum, charge with refrigerant, and start it up. Most crews finish by mid-afternoon.
What slows it down: seized disconnect boxes, rotted pad supports, or asbestos-wrapped lines that need remediation. In older Los Angeles neighborhoods like Highland Park or Eagle Rock, we sometimes find original aluminum wiring that requires pigtailing or replacement before we can safely energize the new unit.
Scenario 2: New Split System with Existing Ductwork (6-10 Hours, Sometimes 2 Days)
You’re adding central AC to a home that has forced-air heating ducts but never had cooling - common in postwar Los Angeles tract homes that originally had wall furnaces or floor heaters. We install a new evaporator coil above the existing furnace, run a refrigerant line set to a new outdoor condenser, and tie into your current duct system.
The variable here is ductwork condition. Los Angeles ducts from the 1950s-1970s are often undersized for cooling, poorly sealed, or routed through inaccessible crawl spaces. We test static pressure and airflow before we commit to using existing ducts. If they can’t handle the additional load, we may need to add a return air pathway or seal significant leaks, which adds hours.
We also see this scenario in homes where the original furnace is being replaced simultaneously. That’s a full system changeout, and while the timeline is similar, coordinating two large pieces of equipment in a tight attic or closet takes more time. For furnace-specific timelines, see How Long Does Furnace Repair Take? Timelines and What to Expect.
Scenario 3: Ductless Mini-Split Installation (1-2 Days)
Ductless systems - one outdoor compressor feeding one or more wall-mounted indoor heads - are increasingly popular in Los Angeles for garage conversions, ADUs, and homes without existing ductwork. A single-zone system with the outdoor unit mounted on a ground pad or wall bracket typically takes four to six hours. Multi-zone systems with three or four indoor heads run a full day or longer.
The time is in the details: drilling through stucco or CMU walls cleanly, running refrigerant lines and condensate drains through finished spaces, and commissioning each zone individually. In hillside homes with limited exterior access, we may need scaffolding or specialized mounting, which adds setup time.
We install Daikin and Rheem ductless systems regularly, and both require precise refrigerant charging based on line-set length. There’s no shortcutting that step.
Scenario 4: Full System with New Ductwork (2-5 Days)
This is the most variable timeline. We’re designing, fabricating, and installing an entirely new duct system while also setting new heating and cooling equipment. In Los Angeles, this scenario comes up in major renovations, additions, or homes where original ducts have been destroyed by rodents, collapsed from age, or simply never existed.
New ductwork requires layout design, material delivery, and often coordination with other trades. A single-story home with accessible attic and crawl space might take two days. A two-story home with finished basement, limited access, or custom architectural features can stretch to a week. We always build in a buffer for inspection scheduling, which we’ll cover next.
| Scenario | Typical Duration | What Extends It |
|---|---|---|
| Replace-in-kind swap | 4-6 hours | Electrical issues, asbestos, pad replacement |
| New split system, existing ducts | 6-10 hours / 1-2 days | Duct repairs, static pressure problems |
| Ductless mini-split | 4 hours - 2 days | Multi-zone, difficult access, wall construction |
| Full system with new ductwork | 2-5 days | Design changes, inspection delays, access issues |
LADBS Permits and Inspections: The Real Schedule Driver
Here’s what most contractors won’t tell you upfront: the Los Angeles Department of Building and Safety (LADBS) inspection schedule often controls your finish date more than the installation crew does.
Permits are required for any new AC installation in Los Angeles, and for most replacements where the electrical load changes or refrigerant type converts. We pull permits on every job that requires them - it’s non-negotiable for us, and it protects your resale value and insurance coverage.
The inspection sequence works like this:
- Rough inspection: After electrical and refrigerant lines are run but before walls are closed or units are fully commissioned. The inspector verifies wire sizing, disconnect placement, and line-set protection.
- Final inspection: After the system is operational, the inspector confirms proper installation, tests safety controls, and signs off on permit completion.
Same-day inspections are sometimes available if we finish early enough to request one before the LADBS cutoff, typically around 2:00 PM for next-day scheduling. In practice, we tell Los Angeles homeowners to expect at least one business day between rough completion and rough inspection, and another day between final completion and final inspection. That means a two-day installation often becomes three or four calendar days.
During peak summer months - June through September in Los Angeles - inspector availability stretches. We’ve seen final inspections pushed to 48 or 72 hours out. We coordinate scheduling proactively, but we don’t control the city’s calendar. Any contractor who promises same-day sign-off in July is either cutting corners or hasn’t done enough jobs to know better.
Some jurisdictions within Los Angeles County use different authorities - Burbank, Long Beach, and Santa Monica have their own building departments with their own schedules. We know the specific requirements for each and build them into our timeline estimates.
Electrical Panel Upgrades in Older Los Angeles Homes
This is the hidden timeline killer we warn homeowners about at the estimate stage. A new AC system in Los Angeles typically requires a dedicated 240-volt circuit with 30-50 amp capacity, depending on the unit size. Homes built before 1970 often have 100-amp service panels that are already at capacity, or fuse boxes that don’t meet current code for HVAC equipment.
When we find an undersized panel during our pre-installation assessment, we flag it immediately. This isn’t a surprise we spring on installation day - it’s a condition we identify and explain before you sign. But it does add a separate trade to your project.
Electrical panel upgrades require a licensed electrician, a separate permit from LADBS, and typically a scheduled disconnect from LADWP (Los Angeles Department of Water and Power). The electrician’s portion takes a full day. The LADWP disconnect and reconnect adds another day, sometimes two if their schedule is tight. Only then can our crew complete the AC installation.
We’ve walked through this process with homeowners in neighborhoods from Venice to Mount Washington. The key is knowing before you commit. Ask your contractor directly: “Will my current electrical panel handle this unit, and if not, what’s the additional timeline and cost?” A firm answer means they’ve checked. A hedge means they haven’t looked, or they plan to figure it out after they’ve started.
What Happens on Installation Day: Hour by Hour
Homeowners often ask whether they need to take the day off work. Here’s what actually happens, so you can plan.
7:30-8:00 AM - Arrival and walkthrough
Our crew arrives in the window we gave you - not “sometime Tuesday,” but “between 7:30 and 8:00 AM.” We walk the job with you, confirm equipment placement, and protect floors and furnishings with drop cloths. This is when we verify the electrical panel assessment one more time and confirm duct access.
8:00-10:00 AM - Removal and prep
We recover any remaining refrigerant from the old system (required by EPA regulations), disconnect electrical and refrigerant lines, and remove the old condenser and coil. We inspect the pad, the disconnect box, and the plenum for damage. If we’re replacing the furnace or air handler, that comes out now too.
10:00 AM-12:00 PM - New equipment set and connection
The new condenser goes on a level pad or vibration isolation mounts. The evaporator coil installs in the plenum. We braze refrigerant connections, run a nitrogen pressure test to check for leaks, and pull a deep vacuum on the lines to remove moisture and non-condensables. This step can’t be rushed - moisture in the system destroys compressors.
12:00-1:00 PM - Electrical and controls
We wire the disconnect, the contactor, the low-voltage control circuit, and the thermostat. In Los Angeles, we see a lot of smart thermostat retrofits at this stage - homeowners upgrading from basic programmable units to WiFi-connected models. We configure and test those too.
1:00-2:30 PM - Startup and commissioning
We energize the system, check refrigerant charge using subcooling and superheat measurements, verify airflow across the coil, and record operating pressures and temperatures. We walk you through the thermostat operation and filter maintenance schedule. We also leave you with the written price you already approved and the written 365-Day Done Right Promise for any repair work.
2:30-3:00 PM - Cleanup and final walkthrough
We remove all debris, old equipment, and protective materials. We do a final walkthrough with you, answer questions, and schedule any needed inspections. You sign the completion paperwork, and we’re gone.
On a two-day job, day one typically ends after the pressure test and vacuum, with the system still uncharged. We return the following morning to complete electrical, startup, and commissioning.
Questions to Ask Before You Sign
The difference between a one-day installation and a week-long ordeal is usually knowable in advance. Here’s what separates a contractor who’s done the homework from one who’s guessing.
- “Have you verified that my electrical panel can handle this unit’s load?” The answer should be specific: “Your 200-amp panel has capacity on slots 14 and 16,” or “You’ll need an upgrade - here’s the electrician we work with and their timeline.” Vague reassurance means they haven’t checked.
- “Will my existing ductwork support the airflow this system needs?” A real answer includes a static pressure target or a plan to test it during the first hour of installation. “Should be fine” is not an answer.
- “Do you pull permits, and what’s the inspection schedule?” Any Los Angeles contractor who says permits “aren’t needed for a swap” is wrong for most jobs, and risky to hire. The follow-up should include realistic inspection timing, not “we’ll get it signed off same day.”
- “What conditions would extend this to a second day?” An experienced crew knows their triggers: electrical complications, duct repairs, line-set replacements, asbestos discovery. They should list them before you ask.
- “Is the price fixed, and what’s included?” At Coldharbour, we put the written price in your hand before any work begins. It includes the equipment, labor, permits, basic electrical, and disposal. Change orders only happen for conditions we couldn’t reasonably foresee - and we explain those clearly if they arise.
The Kingswell Way says we give the price before the work starts, show up in the window given, leave the place cleaner than we found it, put the guarantee in writing, and come back if it fails. That first value - say the price before the work - is how you avoid timeline surprises. A contractor who can’t commit to a number before tools come out probably hasn’t scoped the job thoroughly enough to commit to a schedule either.
Common Mistakes to Avoid
- Assuming all “replacements” are equal. Swapping a 20-year-old R-22 system for a modern R-410A or R-32 unit often requires new refrigerant lines, a new disconnect, and sometimes a new breaker. Ask specifically what’s included in “replacement.”
- Ignoring the permit timeline. In Los Angeles, unpermitted work can derail a home sale and void insurance claims. Factor inspection scheduling into your planning, especially if you’re installing before a closing or rental turnover.
- Choosing equipment size without a load calculation. We perform Manual J load calculations to size equipment correctly. Oversized systems short-cycle, dehumidify poorly, and fail prematurely. This step takes time upfront but prevents callbacks.
- Not asking about the electrical panel until installation day. We’ve seen jobs halt at 10:00 AM because the panel couldn’t accommodate the new circuit. That’s a day lost, and it’s entirely preventable with a pre-installation assessment.
- Expecting same-day completion for multi-zone ductless systems. Each indoor head requires individual commissioning, and multi-zone systems need time for proper refrigerant balancing. A contractor who promises to knock out four zones in four hours is skipping steps you’ll pay for later.
- Neglecting to confirm disposal of old equipment. EPA regulations require proper refrigerant recovery, and California has additional requirements for appliance recycling. Confirm who’s handling this and that it’s included in your price.
- Failing to get the guarantee in writing. Verbal promises don’t help when the compressor fails in month eight. Our 365-Day Done Right Promise is written on every repair, with no ambiguity about what “done right” means.
When to Call a Professional
Call for a professional assessment when your current system is more than 12 years old, requires refrigerant more than once per season, or struggles to maintain set temperature on normal Los Angeles summer days. Call immediately if you hear grinding from the outdoor unit, smell burning from the indoor section, or see ice formation on refrigerant lines - these indicate compressor or airflow problems that worsen quickly.
If you’re planning a renovation, addition, or ADU conversion, involve an HVAC contractor early. Duct routing, equipment location, and electrical planning are far easier to coordinate during design than after drywall is up. We’ve rescued too many projects in Los Angeles where the architect left a 24-inch closet for a 30-inch air handler.
AC Installation in Los Angeles starts with a free, no-obligation estimate from Coldharbour Heating & Air. We’ll assess your home’s specific conditions, explain which scenario applies, and give you a written price and realistic timeline before you commit. Call (817) 402-2972 to schedule.
Frequently Asked Questions
Most AC installations in Los Angeles take four to eight hours and finish in a single day. For more guides & resources on HVAC planning, explore our blog. Replace-in-kind swaps with existing ductwork and adequate electrical service are typically done by mid-afternoon. Jobs extend to two or more days when they require electrical panel upgrades, new ductwork, or scheduled LADBS inspections that can’t be completed same-day. Call (817) 402-2972 for a free estimate with a timeline specific to your home.
Yes, if it’s a straightforward replacement with no electrical or duct complications. We complete roughly 70% of our Los Angeles installations in one day. The remaining 30% involve conditions we identify at the estimate stage - panel upgrades, duct repairs, or multi-zone ductless systems - and we build that into our schedule from the start so you’re never surprised.
Yes, LADBS requires permits for new installations and most replacements. The permit process includes rough and final inspections, which typically add at least one business day each to the overall timeline. We pull permits on every qualifying job and coordinate inspection scheduling as part of our standard process. Unpermitted work can create problems during home sales and insurance claims.
Homes with 200-amp service and available breaker space usually don’t need upgrades. Pre-1970s Los Angeles homes with 100-amp panels or fuse boxes often do, especially if you’re installing a larger unit or adding central AC for the first time. We verify panel capacity during our pre-installation assessment and give you a straight answer before you sign. If an upgrade is needed, we coordinate with licensed electricians we trust and build their timeline into your project schedule.
Replace if your system is over 12 years old, uses discontinued R-22 refrigerant, or has needed major repairs in two of the last three years. Repair makes sense for newer systems with isolated failures covered under warranty or our 365-Day Done Right Promise. We don’t sell equipment you don’t need - our technicians aren’t paid on what they sell, so our recommendation is based on your system’s actual condition and your long-term costs.
Clear a path to the indoor unit and outdoor pad, secure pets in a separate area, and plan to be available for the initial walkthrough and final sign-off. You don’t need to be present for the entire installation if you trust the crew, but someone should be reachable by phone. We protect floors and furnishings with drop cloths, and we leave the job site clean - that’s part of The Kingswell Way. If you work from home, the installation generates normal construction noise for 4-6 hours; plan accordingly for calls or meetings.
The Bottom Line
AC installation in Los Angeles is usually a one-day job, but the conditions that stretch it to two days or longer are almost always identifiable beforehand. The electrical panel, ductwork condition, and permit inspection schedule matter more than the speed of the installation crew. Ask direct questions about these variables before you sign, get your price and timeline in writing, and choose a contractor who identifies complications early rather than discovering them at 9:00 AM on installation day. At Coldharbour Heating & Air, we build our reputation on showing up when we say we will, saying the price before the work starts, and standing behind every job with a written guarantee. That’s been The Kingswell Way since 2003.
Written by Victor Mancini, Owner at Coldharbour Heating & Air, serving Los Angeles since 2003.