Furnace Repair in Boulder, CO
Furnaces here run from September through June. If yours quits, tell us what it's doing and a licensed contractor who covers Boulder County will get in touch.
Tell us about the job
It takes about a minute.
Ten months of heat puts a lot of hours on your furnace
In Boulder County your furnace runs from September through June. Winter nights average 17°F, and on those nights the furnace is what keeps the house warm. That many hours and that many cycles on the igniter and blower motor wear those parts down faster than in a place where the furnace shuts off for most of the year.
Most homes here heat with gas, and a gas furnace still needs power to run the blower and control board even though the flame does not. Boulder County has had 161 winter storms and 120 damaging wind events over the past ten years, and statewide, 13% of households went at least 24 hours without power in 2024. When the power drops on a cold night, the furnace stops with it, and that is often when a homeowner finds out something else was already close to failing.
- 10 months
- September through June, your furnace is on duty
- 17°F
- the average winter night it heats against
- 69%
- of homes here heat with gas, so most furnaces here burn gas
- 161 winter storms
- in ten years, the nights a failure hurts most
NOAA nClimDiv, 1991–2020 normals
A new furnace would cut about $110 a year off heating for a typical Boulder County home.
Estimates for a typical Boulder 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?
- Start with the thermostat. Check that it's set to heat and the setpoint is above room temperature, since a stuck or misprogrammed thermostat is one of the more common reasons nothing happens. Next check the power switch on or near the furnace, which looks like a light switch, and the breaker for it in your panel. If those are fine, the filter may be clogged enough to trip a safety switch that shuts the furnace down before it overheats. When none of this brings it back on, the igniter or a safety control inside the furnace likely needs a contractor to look at it.
- Why is my furnace blowing cold air?
- If air is moving but it's not warm, the furnace may be running the blower without the burners lighting. Check the thermostat fan setting. If it's set to "on" instead of "auto," the blower runs constantly and pushes room-temperature air through the vents between heating cycles, which can feel cold. If the fan is set to auto and you're still getting cold air, the igniter, flame sensor, or gas supply may be the problem, and that's a job for a contractor to diagnose.
- Why won't my furnace pilot light stay lit?
- A pilot light that won't stay lit is usually the thermocouple, the small sensor that tells the gas valve the flame is burning. When it wears out or sits out of position, the valve shuts the gas off as a safety measure even though you just relit it. A draft blowing across the pilot can also blow it out, so check for anything nearby that might be causing airflow near the furnace. If relighting it doesn't hold, the thermocouple likely needs to be adjusted or replaced by a contractor. Furnaces with a standing pilot don't need power to keep that flame burning, so a power issue isn't the cause here.