Furnace Repair Cost in Houston, TX — Winter Price Guide

Furnace repair in Houston follows the same three price tiers as the rest of HVAC, but the parts inside each tier are different, and winter is what exposes them. A minor fix at $150–$450 covers the parts that fail most often after months of sitting idle: hot-surface ignitors, flame sensors, thermostats, and filters. These are the repairs behind most first-cold-night calls, and they are usually finished on the same visit. If your furnace clicks but never lights, or lights and then shuts off within seconds, a minor-tier part is the most likely cause.

A moderate repair at $450–$1,200 covers the working heart of the furnace: blower motors, inducer motors, gas valves, and control boards. A gas valve that will not open, an inducer motor that hums but never spins, or a control board damaged by a winter power surge all land here. These jobs take longer and the parts cost more, but the furnace itself is still sound — one component has worn out, and replacing it restores years of service. This is also the tier where a full burner cleaning and safety inspection sits after a season of neglect.

A major repair at $1,200–$2,800 means the furnace's core is involved: a heat exchanger repair or a major gas-system rebuild. Here the decision changes, because a cracked heat exchanger is not just expensive — it is a safety issue. Carbon monoxide can enter the home's air through a crack, so if we find one we shut the furnace down, test for CO, and lay out the options honestly. In many cases, especially on a furnace over 15 years old, replacement at $4,500–$9,500 is the safer and cheaper long-term answer.

First, the smell of gas. If you smell gas near the furnace, do not flip switches, do not light anything, and do not try to find the leak yourself. Leave the house, call the gas company or 911 from outside, and then call us. A gas leak is a same-day emergency, and it is the one furnace problem where speed matters more than price.

Second, a carbon monoxide alarm. If your CO detector sounds, treat it as real: ventilate, leave the house, and call for help. A cracked heat exchanger or a blocked flue can push CO into the living space, and CO has no smell. We test for carbon monoxide on every gas furnace visit where it is indicated, and we will shut a furnace down rather than leave a family at risk.

Third, a furnace that short-cycles — lighting, running for a minute, and shutting off, over and over. That is often a flame sensor or a limit switch, a minor or moderate repair, but left alone it overheats the heat exchanger and turns a cheap fix into a cracked one. A furnace that behaves strangely in December is telling you something; the cheapest time to listen is the first time it happens.