A furnace that won't heat in Austin is usually a dirty flame sensor, a failed hot-surface igniter, a thermostat or filter problem, or, on a heat pump, auxiliary heat strips that never kicked in. Central Texas cold snaps are short but severe, and the 2021 Winter Storm Uri and the 2023 ice storm showed how fast a house drops below 50°F when heat quits during a rolling outage. Start with the thermostat in HEAT mode, a fresh filter, the furnace power switch and breaker, and the gas supply if you have gas. Common freeze-week repairs typically run $150 to $500, more after hours. If you smell gas, leave the house and call Texas Gas Service first, then a licensed contractor.
Gas furnace or heat pump: figure out which you have first
Most Austin homes built before the mid-2000s and most homes with Texas Gas Service have a gas furnace in the attic or a closet. Newer subdivisions in Kyle, Buda, Leander, and Pflugerville, plus all-electric homes, often have a heat pump, which is the outdoor AC unit running in reverse with electric strips as backup.
Gas furnace checks: thermostat in HEAT, filter fresh, the light switch on the furnace cabinet ON, breaker not tripped, and the gas valve handle in line with the pipe. Listen for the sequence: inducer fan, clicking, ignition, then the blower. Where it stops tells the tech where to look.
Heat pump checks: on a freezing morning the outdoor unit may steam or stop for a defrost cycle, which is normal. Air from the vents that feels cool but not cold usually means the auxiliary strips are not engaging, often a thermostat setting, a tripped strip breaker, or a failed sequencer. Set the thermostat to EMERGENCY HEAT as a stopgap.
The parts that fail during Central Texas cold snaps
Flame sensor. A furnace that lights, runs a few seconds, and shuts off has a flame sensor coated in oxidation from sitting idle through nine warm months. It is the most common winter call in Austin and one of the cheapest fixes.
Igniter and pressure switch. A hot-surface igniter cracks after years of thermal cycling, and a pressure switch can fail when a flue is blocked or a condensate trap freezes. Both stop the ignition sequence before any flame.
Filters and airflow. Cedar pollen season peaks in December through February, exactly when the furnace runs. A clogged filter overheats the heat exchanger and trips the high-limit switch, so the blower runs but the burners cycle off. Replace the filter before assuming a part has failed.
Rolling outages, safety, and when to call
After a rolling outage or a grid event like Uri or the 2023 ice storm, many furnaces need only a reset: cycle the furnace switch off for 30 seconds, then on. Heat pumps may need the outdoor breaker cycled too. Do not run a generator, grill, or camp stove indoors under any circumstances.
Call a licensed contractor when the ignition sequence stops at the same point every time, when the breaker trips repeatedly, or when a heat pump runs but the house keeps losing ground. During a freeze, contractors triage no-heat calls; mention infants, elderly residents, or medical needs in the home.
LocalFixQuotes is a free matching service and not a contractor. We connect Austin homeowners with independent, TDLR-licensed HVAC contractors who diagnose furnace and heat pump problems and quote the repair. There is no obligation to hire.
Next step
Get furnace repair quotes from checked Austin HVAC contractors
LocalFixQuotes matches you with up to 4 independent local HVAC contractors. Free for homeowners, no obligation, and we don't perform the work ourselves.
Get my free quotes