HVAC Repair in Boulder, CO
If your system 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.
Boulder County asks a lot of your furnace, most of the year
Your furnace runs from September through June here. That is ten months of the year, with only a short stretch where it can rest. Winter nights average 17°F, and on those nights the burner cycles on and off many times to keep up. Each cycle puts wear on the igniter and the flame sensor, and those are usually the first parts to fail. When one does, the furnace stops firing and the house goes cold fast at 17°F.
Summer afternoons here average 78°F, mild enough that most homes lean on the furnace far more than the AC. Nearly seven in ten households heat with gas, so when something goes wrong in the cold months, it is usually the furnace, not the heat pump or the coil. Boulder County has also logged 161 winter storms and 120 damaging wind events over the past ten years, and statewide, 13% of households lost power for a day or more in 2024. A furnace with a standing pilot will relight on its own after an outage. One with an electronic igniter will not, and needs a switch flipped or a reset before it fires again.
- 10 months
- September through June, your system heats
- 17°F
- the average winter night it heats against
- 78°F
- the average summer afternoon it cools against
A new furnace and air conditioner would cut about $110 a year off heating and cooling 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.
Replacement makes sense when the furnace's heat exchanger is cracked, the air conditioner's compressor has failed, or repairs keep coming.
- Why is my heat not working?
- Start with the thermostat. Make sure it's set to heat and the temperature is set above the room temperature, since a setting bumped by accident is a common cause. If the thermostat looks right, check your breaker panel for a tripped breaker and check that the furnace switch, the one that looks like a light switch near the unit, is on. Gas furnaces also need the pilot lit or the igniter working, so if you hear the blower running but get no heat, that points to an ignition problem a contractor will need to look at. With winter nights here dropping to 17°F on average, a furnace that won't start is worth getting checked the same day.
- Why is my system running but not cooling the house?
- The most common cause is a dirty air filter blocking airflow, so check that first and replace it if it's gray or clogged. If the filter is clean, look at the outdoor unit and clear away any leaves, dirt, or plant growth pressing against it, since it needs open airflow to release heat. A system that runs constantly without cooling can also mean it's low on refrigerant, and that's not something to add yourself. It always needs a contractor to find the leak and repair it, since refrigerant doesn't get used up under normal operation.
- What can I check before calling for HVAC repair?
- Check the thermostat settings first, since a wrong mode or a battery running low can look like a bigger problem. Check the breaker panel for a tripped breaker and make sure any power switch near the furnace or air handler is in the on position. Look at the air filter and replace it if it's dirty, since restricted airflow causes a lot of the calls contractors get. If the outdoor unit is involved, make sure nothing is blocking it. If you've checked all this and the system still isn't working, a contractor can diagnose what's left, and given how many homes here rely on heat for most of the year, it's worth getting on the schedule quickly rather than waiting it out.