What does a new AC cost here?
For most St. Louis homes, a complete central air-conditioning replacement falls in the mid-four-figure to low-five-figure range installed — a straightforward like-for-like swap sits at the lower end, while high-efficiency systems, larger homes, or jobs that also correct ductwork land higher. The single biggest mistake is shopping on the bottom-line number alone instead of the equipment, scope, and warranty behind it.
Because every home is different, the only way to get a firm, accurate figure is a free, no-obligation written estimate — the cost factors below (system size, efficiency tier, the condition of your ductwork, and the rebates you qualify for) are what move your number up or down.
What drives the price?
Five factors move an AC quote the most:
- System size (tonnage) — set by a load calculation, not square footage
- Efficiency (SEER2) — higher-SEER2 inverter systems cost more upfront, less to run
- Refrigerant — new R-454B (A2L) equipment runs ~$400–$1,200 more than the old R-410A tier (2025 phase-out)
- Ductwork — undersized or leaky ducts may need correction for the new system to perform
- Rebates — Ameren Missouri PAYS (up to $1,000 AC / $2,000 heat pump) can offset the upgrade
How to avoid overpaying
Get an itemized quote (equipment make/model, SEER2, scope, permit, warranty), make sure it's sized from a load calculation, and confirm which rebates apply. If you already have a quote, a free second opinion is the fastest way to check it apples-to-apples.
How Degenhardt prices it
We quote the equipment you actually need, size it properly, show repair vs. replacement options with real numbers, and handle the rebate paperwork — free estimates, transparent pricing, no pressure.
Frequently asked questions
Often yes — our long, humid cooling season means a higher-SEER2 system can recover its premium through lower bills, and Ameren PAYS rebates narrow the upfront gap. We model the payback for your home before you decide.
New equipment switched from R-410A to low-GWP R-454B refrigerant under the EPA AIM Act, adding roughly $400–$1,200 to a typical system. It also makes repairing a leaking old R-410A unit costlier, which can tip the decision toward replacement.
A complete installed quote from Degenhardt covers removal/disposal of the old equipment, the new system, and the permit where required. Always confirm these are itemized on any quote you compare.