What a New Central Air Unit Actually Costs
Installed pricing depends on tonnage, efficiency rating, and whether your existing ductwork can be reused. As of 2026, most homeowners land somewhere between $4,500 and $12,500 installed, with the spread driven almost entirely by SEER2 rating and ductwork condition.
| System | Installed cost | Typical home size |
|---|---|---|
| 3-ton, standard efficiency (16-17 SEER2) | $6,500-$9,500 | ~1,800 sq ft |
| 3-ton, budget/reused ductwork | $4,500-$8,500 | ~1,800 sq ft |
| 4-5 ton, variable-speed (18+ SEER2) | $10,500-$15,000+ | 2,500+ sq ft |
| New ductwork (add-on) | +$3,000-$7,000 | — |
Source: RealCostIQ, FixUpFirst 2026 cost data.
New units as of 2026 also run on R-454B or R-32 refrigerant under updated EPA rules, which added roughly 10-15% to equipment cost compared to a few years ago. That's not a fee you can shop around — it's baked into every current model.
What SEER2 Actually Means
SEER2 measures cooling output per unit of electricity used over a season, tested under more realistic airflow conditions than the old SEER rating. Higher is more efficient, but the payback math depends on your climate.
- 14.3 SEER2: current minimum in most US regions. Fine for a mild climate with a short cooling season.
- 15-16 SEER2: the sweet spot for most homes — a modest premium over the minimum, with a real efficiency gain.
- 18+ SEER2, variable-speed: costs $2,000-$4,000 more than a standard unit. Worth it in hot climates with long cooling seasons; in a mild one, you may never earn the premium back.
Sizing It Right
A unit that's too big cools the room fast, shuts off, and leaves the house humid. Too small runs constantly and never quite catches up on the hottest days. Square footage alone isn't a reliable guide.
- Rough starting point: about 1 ton of cooling per 500-700 sq ft, adjusted for climate.
- What actually changes the number: insulation quality, window count and orientation, ceiling height, attic ventilation, and how many people typically use the home.
- The real answer: a Manual J load calculation from your installer. Any contractor who quotes a size off square footage alone without asking about your insulation or windows is skipping a step that affects both comfort and your bill for the next 15 years.
What to Ask an Installer
- "Can you show me the Manual J calculation for this size, not just a square-footage estimate?"
- "Is my existing ductwork sized correctly for this unit, or does it need modification?"
- "What's the SEER2 rating, and what's the price difference to go one tier up?"
- "What refrigerant does this unit use, and is it R-454B or R-32?"
- "What's the full installed price, including any electrical or ductwork work — not just the equipment?"
An Honest Note on Rebates
Straight air conditioner replacement — swapping an old AC for a new one, furnace untouched — doesn't typically qualify for the rebate programs listed on this site. Those programs are built around heat pumps, which do the same cooling job as an AC but also handle winter heating, replacing your furnace at the same time.
If your AC and furnace are both getting old, it's worth pricing a heat pump conversion before you commit to a straight AC swap. You lose nothing by asking for both quotes, and the rebate math can meaningfully change the total cost comparison.