Even San Antonio gets cold sometimes
Reliable Heating Contractor in San Antonio
Ask a heating contractor in San Antonio what fails most and you’ll hear igniters, flame sensors, and tired gas valves.
Getting cozy is a lot easier when the heat works
Did you know?
San Antonio hit 100 degrees on 58 days in 2022 and 75 days in 2023, the hottest year on record here. That’s more than two months of triple digits. Every one of those days is runtime your compressor never gets back.
Questions & Answers
Start with the thermostat setting and batteries, the filter, and the furnace door switch, which has to be seated for the unit to fire. After that, the usual causes are a dirty flame sensor, a cracked hot surface igniter, a tripped high-limit switch, or a closed gas valve. San Antonio furnaces sit idle for months, so the first cold front is when those parts show their age. Don’t keep cycling a unit that tries and fails, because repeated ignition attempts lock the control board out.
Winter Storm Uri hit San Antonio in February 2021 with a 9-degree low and roughly 107.5 straight hours below freezing, and rolling blackouts cut power to about 300,000 CPS Energy customers at peak. Heat pumps sat in defrost or fell back on strips they weren’t sized for, and undersized gas furnaces ran nonstop without keeping up. Burst water lines and a SAWS boil notice followed. The December 2022 arctic blast was the hardest cold since, and it caught a lot of the same systems.
Furnace repair pricing depends on the failed part, whether the system is gas or electric, how old the unit is and whether parts are still made for it, how tight the closet or attic access is, and whether you’re calling during a freeze. An igniter or flame sensor is a small part and a short visit. A heat exchanger or control board on a 20-year-old furnace is a different conversation, and on a unit that old the money often belongs in a replacement instead. Absolute Zero explains both paths before anything gets ordered.
Yes, heat pumps heat well through most San Antonio winters, and Absolute Zero installs and services them across the northwest side. They do lose capacity as outdoor temperatures fall toward freezing. That’s what auxiliary heat strips are for, and sizing those strips correctly is what separates a comfortable house from a cold one during an event like February 2021. Homes on the far northwest side running heat pumps should have the defrost cycle and backup heat checked before December. A heat pump with a working backup plan handles a Texas freeze fine.
A furnace burns gas to make heat. A heat pump moves heat using the same refrigerant cycle the AC uses and runs on electricity, so one piece of equipment heats and cools. In San Antonio’s mild winters a heat pump is efficient most days, while a gas furnace delivers hotter air on the coldest mornings. Gas availability decides it for many homes, especially outside the city where propane is the alternative.
Dust burning off the heat exchanger is normal on the first run of the season, and it usually clears within an hour. San Antonio systems sit unused from March into November, so there’s plenty of dust to burn. A smell that keeps coming back, turns acrid or electrical, or comes with soot means shut it off and get it looked at. A burning smell with a carbon monoxide alarm is an emergency, so get everyone outside and call from there.
October is the right month, before the first real cold front. A heating tune-up checks the igniter, flame sensor, gas pressure, heat exchanger, blower, and safety controls while there’s no rush to get heat back on the same night. Cold fronts start pushing through San Antonio in November, and that’s when no-heat calls stack up. Absolute Zero books plan members’ heating visits in the fall so the check happens before the cold does.
A cracked heat exchanger shows up as a flame that flickers or rolls when the blower kicks on, soot around the burners, an acrid smell, water pooling near the unit, or headaches and nausea in the house. Any carbon monoxide alarm means everybody goes outside first, then calls. A tech confirms it with a visual inspection and a combustion test. A cracked exchanger can’t be repaired, so the furnace gets replaced, and the gas stays off at the unit until it is.
Air is moving, so the problem is usually heat output or heat loss. A heat pump stuck on backup strips, a furnace running on one stage, a dirty filter choking airflow, or leaking attic ducts all deliver lukewarm air at the registers. On San Antonio’s northwest side, duct connections take a beating from expansive clay soil that moves slabs and pulls joints apart. Absolute Zero measures temperature rise across the unit and checks the duct system before anyone talks about new equipment.
Replacing both together usually makes sense when the systems share the same age, the indoor coil sits on top of the furnace, and the refrigerant type is changing. Matched equipment reaches its rated efficiency, and a new condenser paired with an old coil rarely does. If the furnace still has good years left, Absolute Zero will say so and replace the cooling side only. Doing both at once also means one install day and one crew in the house instead of two.
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