How Long Does It Take to Replace an AC Unit?
- Jayant Upadhyay
- Jul 16
- 5 min read
Air conditioning isn’t just a luxury in today’s world—it’s a necessity, especially during the sweltering summer months. When your AC unit breaks down beyond repair, replacing it becomes urgent. But one of the most common questions homeowners ask is: How long does it take to replace an AC unit?
The short answer: It typically takes 4 to 8 hours to replace a standard central air conditioning system. However, the time frame can vary depending on several factors, including the type of AC unit, complexity of installation, ductwork condition, and the experience of your HVAC technician.
In this comprehensive guide, we’ll break down everything that goes into AC replacement time, including timelines, influencing factors, what to expect on installation day, and tips to speed up the process without compromising quality.
Table of Contents
What Does AC Replacement Involve?
Replacing an air conditioning unit involves more than just swapping out the old system for a new one. A professional HVAC team must:
Disconnect and safely remove the old unit
Inspect and possibly upgrade electrical connections
Evaluate ductwork and refrigerant lines
Properly size and install the new unit
Test for efficiency, leaks, and airflow
Program the thermostat and ensure system calibration
Each step takes time, especially if your HVAC system is outdated or the new unit uses different technology.
Average Time to Replace Different Types of AC Units
AC Unit Type | Replacement Time Estimate |
Central Air Conditioner | 4–8 hours |
Ductless Mini-Split System | 6–10 hours (1 indoor unit) |
Multiple-Zone Mini-Splits | 1–2 days (2–4 indoor units) |
Window Units | 30–60 minutes (DIY) |
Packaged Units (Rooftop) | 6–12 hours (crane may be needed) |
Pro Tip: If your new system includes additional zoning, smart thermostats, or ductwork changes, the job may extend to 1–2 days.
Factors That Affect AC Replacement Time
Unit Type and SizeLarger or more advanced units take longer to install.
Ductwork ConditionCracked or poorly sealed ducts must be repaired or replaced, adding 4–8 hours or more.
Electrical System CompatibilityOutdated wiring or circuit upgrades may delay the process.
Refrigerant Line ReplacementSwitching refrigerants (e.g., from R-22 to R-410A) requires new copper lines.
Permits and InspectionsLocal codes may require a city permit and inspection before activation.
AccessibilityUnits located in attics, crawl spaces, or rooftops require more setup time.
Step-by-Step Breakdown of the AC Replacement Process
1. Pre-Installation Site Inspection (1–2 hours)
Evaluate existing system
Determine AC size and placement
Discuss duct, insulation, and thermostat conditions
Estimate timeline and cost
2. Old Unit Removal (1–2 hours)
Recover refrigerant safely (EPA requirement)
Disconnect electrical and line connections
Remove outdoor and indoor components
Prepare site for new unit
3. Duct and Electrical Work (Optional – 2–6 hours)
Seal or replace ductwork
Update electrical panel or wiring
Modify refrigerant lines as needed
4. New AC Installation (3–5 hours)
Place outdoor condenser and indoor air handler
Connect electrical and line sets
Secure unit on concrete pad or wall bracket
Charge refrigerant
5. Testing and System Calibration (1 hour)
Check airflow, cooling levels, and thermostat sync
Inspect for leaks and safety issues
Confirm system performance
Timeline for Ductwork Inspection and Repair
Poor ductwork = poor performance. If your HVAC contractor identifies issues, expect:
Minor sealing or cleaning: 2–3 additional hours
Moderate repairs: 1 full day
Full duct replacement: 1–2 extra days
Upgraded ducts improve efficiency and system longevity, so this step is worth the time.
Old Unit Removal: What to Expect
Your HVAC team will:
Disconnect power and thermostat connections
Drain and recover refrigerant (legally required)
Remove indoor coils and outdoor condensers
Haul away the old unit (ask if disposal fees apply)
Removing the old unit is usually quick, but complications (e.g., tight attic access) can add time.
New AC Unit Installation Time
Installation time depends on:
Unit type: A central system is faster than a multi-zone mini-split.
Experience: Skilled technicians work more efficiently.
Pre-site prep: Concrete pads, wall mounts, or drainage systems add time.
For most central AC systems:🕒 3–5 hours of focused work
Post-Installation Testing and Setup
This step ensures everything runs as expected. Technicians will:
Test air pressure and refrigerant levels
Calibrate the thermostat
Inspect noise levels
Walk you through operation and maintenance
Never skip this—proper setup prevents issues and ensures energy efficiency.
Same-Day vs. Multi-Day AC Installations
✅ Same-Day Installations (Most Common)
If you're replacing a similar unit without ductwork updates or rewiring, you’ll likely enjoy same-day comfort.
⚠️ Multi-Day Projects
Required when:
Ductwork needs repairs
Unit location changes (e.g., from ground to attic)
Electrical panel must be upgraded
Weather causes outdoor delays
Plan for 2–3 days if complications arise.
Common Delays and How to Avoid Them
Permit delays – Confirm permits early
Equipment shipping – Choose in-stock models
Unexpected duct damage – Get a duct camera inspection beforehand
Weather conditions – Avoid scheduling during extreme storms
Unlicensed installers – Always hire certified HVAC technicians
Tips to Speed Up Your AC Replacement
✅ Choose a reputable, local HVAC contractor
✅ Select a system that matches your existing layout
✅ Get pre-installation inspection and approval
✅ Clear work areas inside and outside your home
✅ Schedule in off-peak seasons (spring/fall)
Proactive planning means faster, smoother replacement—and fewer surprises.
Frequently Asked Questions (FAQs)
Can I stay home during installation?
Yes, and it's often encouraged. Installers may have questions about access, power, or thermostat settings.
Will I be without AC all day?
Yes, you’ll have no cooling during installation. If it’s hot, plan to spend time in a cooler part of the house or step out temporarily.
How much does AC replacement cost?
Average cost in 2025: $5,000–$9,000, depending on unit size, SEER rating, and complexity.
Should I replace my furnace at the same time?
Often yes—doing both at once may save labor costs and ensure system compatibility.
Final Thoughts
Replacing your AC unit is a major investment, but it doesn’t have to be a major disruption. With the right contractor and preparation, most homeowners can expect a full replacement in 4–8 hours, with a few rare exceptions extending into multiple days.
The key is understanding the scope of your project. Factors like ductwork, unit type, and site access can add or subtract hours from the timeline.
Looking for fast, reliable AC replacement? Choose a licensed, experienced HVAC professional who can evaluate your system and deliver a seamless installation with minimal downtime.
Need help finding the right AC unit or technician?Stay cool—let us guide you to trusted pros in your area.
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