What does a new furnace cost here?
Most St. Louis furnace replacements land in the mid-four-figure to low-five-figure range installed. A standard ~80% AFUE furnace sits at the lower end; a 90%+ high-efficiency condensing furnace (which may qualify for a Spire rebate) costs more upfront but burns less gas all winter.
For a firm number on your home, the most reliable step is a free, no-obligation written estimate — the efficiency tier (AFUE) you choose, the furnace size your home needs (set by a load calculation), and any venting, gas, or electrical work are what set the final price.
What drives the price?
The main cost drivers:
- Efficiency (AFUE) — 80% vs. 90%+ condensing changes both price and venting
- Size (BTU output) — matched to the home by load calculation
- Venting & gas — condensing furnaces need new PVC venting; gas-line or electrical work adds cost
- Rebates — Spire offers up to $300 on a qualifying 96%+ AFUE furnace
- Whether a heat pump is a better fit (it also cools, and Ameren rebates apply)
How to avoid overpaying
Insist on an itemized quote with the model, AFUE, venting scope, and warranty, and ask whether a heat pump or high-efficiency furnace pays back better for your home. We'll run that comparison honestly.
How Degenhardt prices it
Union-trained, NATE-certified installs, sized correctly, with a combustion safety check and the rebate paperwork handled. Free estimates and transparent pricing since 1984.
Frequently asked questions
A 90%+ condensing furnace burns less gas through our cold season and may earn a Spire rebate, but costs more upfront and needs PVC venting. An 80% furnace is cheaper to install. We model the payback for your home and usage.
Often worth comparing — a heat pump heats efficiently most of our season and also cools, frequently with Ameren rebates. It depends on your ducts, gas availability, and budget; a free estimate sorts it out.
In most St. Louis-area jurisdictions a furnace changeout requires a mechanical permit and inspection. Degenhardt handles the permit when your job needs one. See our permits guide for details.