There isn’t a single average cost to fix a furnace; Air Comfort Service, Inc. confirms pricing after an on-site diagnosis. Our service call is $99, and our emergency HVAC service call is $199, plus repairs. Most repair totals depend on which component failed and whether the visit is after-hours. Expect a transparent flat-rate quote before work begins. We offer free second opinions on costly issues like heat exchangers. Our technicians have decades of experience with systems throughout the St. Louis area, including Ballwin. Minor part failures are usually repaired, while severe safety problems or very old units may point to replacement. A quick way we gauge scope is by checking ignition sequence timing and blower motor amperage under load.
Costs tend to rise when any of the following apply:
- Multiple failed parts in the same visit
- Hard-to-access equipment (attic or crawlspace)
- Safety corrections needed for venting or controls
If you ever smell gas or suspect a cracked heat exchanger, turn the furnace off and call a licensed professional immediately.
Updated: 2026-07-29
Need help in Ballwin, MO? Call 3148148455 or book online. "Very positive. Called early today to report furnace stopped working. Antonio was here quickly and found issue and repaired. He was friendly and very competent." — Firstname L.