Furnace repair
No-heat calls come in waves here: the first real cold snap of the season finds every furnace that spent the summer quietly developing a problem. Most of those problems are small. The visit exists to fix the small one, and to say honestly whether it was a symptom of a bigger one.
What fails, most of the time
The usual suspects on a gas furnace are cheap and quick: a flame sensor coated in oxide that shuts the burner down seconds after ignition, a failed ignitor, a pressure switch reading a blocked flue or intake, a blower capacitor. On heat pumps, and Kentucky has a lot of them, the calls cluster around defrost boards, reversing valves and the auxiliary heat that quietly takes over and doubles the bill. A technician who works the sequence of operation finds these in under an hour.
The part that deserves respect is the heat exchanger. It is the wall between the flame and the air your family breathes, and on a furnace deep into its service life it is the component age attacks. A cracked exchanger is a replace-the-furnace finding, and a serious shop will show you the crack, on camera, in the report, rather than asking you to take a condemnation on faith. If the finding comes with pressure to sign tonight, the second opinion is worth the cold evening it costs.
The winter arithmetic
Repair-or-replace runs on the same logic as cooling, with one Kentucky twist: many homes here heat with a heat pump plus electric backup, and a failing heat pump can hide for weeks behind its own auxiliary heat, the house stays warm while the meter runs wild. A January power bill far above the neighbors’ is a service call in disguise.
On timing: the first cold week of the season is the busiest week of the trade’s year. A furnace that struggled at the end of last winter, long ignition, short cycles, a burner smell, is telling you in October what it will do in December, and an October visit gets attention and parts that a December wave does not. The fall check is not upsell; it is queue-jumping.
Quick answers
- Why did the furnace quit on the first cold night?
- Months of summer idleness plus the first real load is exactly when a marginal ignitor, flame sensor or pressure switch gives up. It is the most predictable failure date of the year, and the busiest, which is why a fall check beats a December wait.
- My heat pump runs constantly in winter, is it broken?
- Not necessarily: below freezing, long run times are how a heat pump is designed to work. The signals that earn a service call are a bill far above normal (auxiliary heat covering a failing unit), ice that never clears off the outdoor coil, or indoor air that blows cool for long stretches.
- 1 Thermostat. Where short cycles are noticed, and rarely where they start.
- 2 Return and filter. The lungs. Starve them and every part upstream works harder.
- 3 Furnace. Ignition parts fail first; the heat exchanger is the finding that ends a furnace.
- 4 Indoor coil. Where cooling also dries the air, or fails to and leaves the house clammy.
- 5 Crawl-space ducts. Every leak down here feeds the crawl space instead of the far bedroom.
- 6 Outdoor unit. Coil, capacitor, and the defrost cycle that carries it through winter.