How much does it cost to install central air with ductwork?

The cost to install central air with new or upgraded ductwork is confirmed after an in‑home evaluation because equipment size, duct design, and home layout drive the price. Most budgets are set by the home’s square footage and how much ductwork must be added, resized, or sealed. If existing ducts are in good shape, reusing them can lower costs; if they’re leaky or undersized, replacement raises labor and materials. We install complete systems across the Peninsula and plan for attic access and older framing common in local homes. A straight, well‑sealed trunk line often saves more noise and energy than upsizing the outdoor unit. A current site offer provides $100 off AC system installation.

Expect estimates to call out:

• Electrical circuit/panel needs and safe condensate drainage
• Access factors that change labor hours (attic height, crawlspace)
• Return air sizing and number of supply registers for room balance
• Thermostat options and filtration/IAQ upgrades

Schedule a load calculation and duct inspection to get a firm, written quote. <br/> Updated: 2026-04-13 <br/> Need help in Atherton, CA? Call (628) 222-4283 or book online. “Great experience with Magic Plumbing to install AC… efficient… workers were professional and friendly.” — Lauren D.