Furnace Repair in Thornton, CO
Furnaces here run from October through May. If yours quits, tell us what it's doing and a licensed contractor who covers Adams County will get in touch.
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Eight months of Thornton winters wear a furnace down
Your furnace works from October through May here, eight months of the year. On nights that average 16°F, it cycles on and off for hours at a stretch to hold the house at temperature. Every one of those starts depends on the igniter to light the burner. That part wears with each use, and when it finally gives out, the burner will not light at all.
Most homes in Thornton heat with gas. Power still matters. Across Colorado, 13% of households went at least 24 hours without power in 2024. A furnace with no power will not run its blower or its ignition system, no matter how sound the rest of it is.
- 8 months
- October through May, your furnace is on duty
- 16°F
- the average winter night it heats against
- 69%
- of homes here heat with gas, so most furnaces here burn gas
- 50 winter storms
- in ten years, the nights a failure hurts most
NOAA nClimDiv, 1991–2020 normals
A new furnace would cut about $100 a year off heating for a typical Adams County home.
Estimates for a typical Adams County home, compared with an older unit built to the previous federal minimum, from EIA household energy data, Colorado fuel prices and NOAA climate normals. Your home will differ.
Repair makes sense when one part has failed and the heat exchanger is sound.
Replacement makes sense when the heat exchanger is cracked or the furnace keeps needing parts.
- Why won't my furnace turn on?
- Check the thermostat first, since a dead battery or a setting bumped to off will stop the furnace before it ever starts. If the thermostat looks right, check the breaker and the furnace switch, the one that looks like a light switch on or near the unit itself. Furnaces this old winter will run for hours at a stretch, so a tripped breaker or a clogged filter starving it of airflow can cause it to shut itself down as a safety measure. If power and airflow both check out and it still won't start, the igniter or a safety switch inside the unit likely needs a contractor to look at it.
- Why is my furnace blowing cold air?
- Most often this means the blower is running but the burners haven't lit. Check that the thermostat is set to heat and not just fan, since a fan set to run continuously will push room-temperature air even when the furnace isn't heating. If the setting is right and you still feel cold air, the igniter or the gas valve may have failed, and with nights averaging 16°F here that's worth having a contractor check the same day rather than wait it out.
- Why won't my furnace pilot light stay lit?
- A pilot that won't stay lit usually points to the thermocouple, the small sensor that tells the gas valve the flame is burning. When it wears out or sits out of position, it reads no flame and shuts the gas off even though the pilot was lit a moment ago. A draft blowing across the pilot or a dirty pilot orifice can also snuff it out. Relighting it yourself only tells you the thermocouple needs replacing if it goes out again soon after, and that part is worth having a contractor swap before the coldest stretch of winter hits.