Furnace repair in San Antonio, for the weeks winter actually shows up

The failures we see every cold season

It will not light, or lights and quits

This is the call that opens every cold season here, and it opens it on the first cold night for a simple reason: that is the first time since March anyone has asked the furnace to work. A modern furnace lights by passing a series of checks in a fixed order: draft established, ignitor hot, flame lit, flame sensed. Fail any check and the furnace stops itself, by design, because the order exists to keep unburned gas out of your house. Seven idle months are hard on exactly two parts, the ignitor and the flame sensor, and they are the gentlest repairs on this page. Apartment work teaches you to expect them in batches: a street of same-vintage furnaces tends to make the same first-cold-night call, house after house, like a roll call.

A heat pump that cannot keep up, or never stops

Much of the stock between and outside the loops heats the way it cools, with the outdoor unit running in reverse. A heat pump moves heat rather than making it, and on the coldest San Antonio nights it runs long hours and leans on its backup heat to hold the line. That much is design. Ice that builds on the outdoor unit and never clears in the defrost cycle is not. A house losing ground hour by hour is not. Backup heat carrying the house alone for days is not, and that one announces itself on the electric bill before it announces itself anywhere else. Each of those is a pattern story: refrigerant, airflow, or controls reporting outside its band, in a system whose twin down the street may be reporting the same thing this week.

It runs, but the house stays cold

Somewhere between the furnace and the far bedroom, the heat is being lost or never made at full strength. Start with the filter: the one that finished cooling season is the one heating season inherits, and a loaded filter throttles the whole system before anything else gets a vote. Past the filter, the suspects are a blower giving up speed a little at a time, duct runs leaking into a cold attic, or a burner that lights and quietly drops out early. In the apartment years this was the call that separated diagnosis from guessing: the equipment room said one thing, the far bedroom said another, and the truth lived in the duct path between them.

It short cycles

Three minutes of heat, five minutes of silence, repeated until bedtime. A system living that way never settles into its work, and it ages with every restart. Read it as a sentence with several possible authors: a filter so loaded the furnace trips its own safety limit, a thermostat mounted where a supply vent or a sunny wall lies to it, a furnace too big for its house warming the hallway and declaring victory, or a limit switch reporting a system that truly is running too hot. When it started matters more than how it sounds, so tell us the week you first noticed it. In a freeze week, the systems that short cycled in December are the no-heat calls of January.

Cold rooms at the ends of the house

Every San Antonio housing era has its version: the back bedroom in a 1960s Windcrest ranch, the room over the garage in a two-story Schertz plan, the far suite in a Garden Ridge house with the longest duct run in the county. Sometimes the furnace is innocent and the ductwork is undersized, disconnected, or never balanced for the house as it exists now. Sometimes the nothing is broken at all, and the system is only smaller than it used to be, worn down to a fraction of its young capacity. Either way the honest answer starts with temperatures measured in the cold room and at the equipment, compared, and with your floor plan's known habits in mind.

The thermostat is blank, or lying

Rule the small liar out first. A dark screen is often nothing grander than a dead battery, and sometimes it is a safety switch that cut power to the controls because the drain pan filled. A thermostat reporting 72 in a room your skin says is 65 is usually placed badly: on a wall the afternoon sun works over, or close enough to a supply register to sample the product instead of the room. And after a freeze with outages, a blank thermostat can be the visible tip of a board that took the surge when the power came home. None of these is a furnace replacement. All of them get priced as one if nobody rules them out first.

Think of heating as a series of gates

A furnace rewards the same thinking as an apartment work order, because it is the same discipline from the other end of the year. Think of it as a series of gates, each one opening only when the last one's condition is met: draft, ignition, flame sense, heat rise, delivery, exhaust. A failure is a gate that stayed shut, and the diagnosis is finding which one. A heat pump runs the cooling path backward and adds two gates of its own, the defrost cycle and the backup heat stage.

That is why the first questions on our calls are about the house as much as the system: what year, which side of town, what did it do on the last cold night. A furnace that sat idle from March to November and quit on the first freeze is telling a different story than one that has short cycled since the season turned. What you tell Gwen is the visit's first page. The visit turns the rest.

Why this page stands beside the cooling page

Heating is the second service because San Antonio winter is short, not because it is trivial. The freeze of February 2021 is the reference: days below freezing, pipes bursting across the metro, and heat pumps and furnaces failing under loads they see once a decade. A crew that only thinks in cooling is not ready for that week, and a portfolio man has seen that week arrive as three hundred work orders at once. This page exists so the heating intent has a real home, the freeze calls have a crew that expects them, and the launch shape stays at exactly two services.

House losing heat now? Call for same-day help, or ask for the free estimate and let Gwen sort the timing.