No heat or weak airflow
The cause may involve the thermostat, filter, blower, ignition system, ductwork, or another part of the system.
Furnace diagnosis and service
Furnace Repair in Boulder, CO
No heat, short cycling, weak airflow, unusual noise, or an ignition problem can have different causes. Mesa evaluates the furnace and connected system before explaining repair or replacement options.
Licensed & InsuredEvidence-led recommendationCalls 7 AM to Midnight
Direct answer
What should you do when the furnace stops heating?
Check the thermostat setting, the filter, and the breaker without opening the equipment. If you smell gas or a carbon monoxide alarm sounds, leave the area and follow utility or emergency guidance before doing anything else. A service evaluation can identify whether the issue is in the furnace, controls, airflow, or connected duct system.
When to evaluate
Furnace problems Mesa can evaluate
Furnace symptoms can overlap, so the equipment and heating system should be inspected before a repair is selected.
Short cycling
A furnace that turns on and off repeatedly can point to an airflow restriction, flame sensor issue, overheating protection, or thermostat problem.
Banging, rattling, or squealing
Record when the sound occurs and any displayed code so the technician has useful diagnostic context.
Ignition or pilot trouble
A furnace that will not light, or that lights and drops out, may have an igniter, flame sensor, gas valve, or venting condition that needs evaluation.
Service process
Furnace service guided by diagnosis
Mesa evaluates the furnace and system behavior before recommending a component repair, further testing, or replacement path. Gas equipment at Boulder's elevation also needs the right combustion setup, which is checked as part of the evaluation.
Describe the heating problem
Share which rooms are affected, when the symptom began, and any displayed code or unusual sound or smell.
Inspect the furnace and system
The evaluation considers the unit, ignition, flame sensing, blower, filter, venting, controls, and reported behavior.
Review the recommendation
Mesa explains the observed condition and the work that may address it.
Complete approved work
After the homeowner approves the selected path, the service can be completed and the system checked.
Choose by condition
Furnace repair, service, or replacement?
The decision depends on the failed component, equipment age and condition, repair history, efficiency, and installation requirements.
Request an EvaluationFurnace repair
May fit an isolated serviceable component such as an igniter, flame sensor, blower motor, control, or thermostat problem.
Furnace service
May be appropriate when the system needs evaluation, cleaning, adjustment, or preventive attention rather than a replacement decision.
Furnace replacement
May deserve consideration when the equipment has a major failure such as a heat exchanger problem, recurring breakdowns, or a condition that makes repair impractical.
Request service
Request furnace service
Share whether the furnace has stopped heating, is short cycling, shows a code, is making unusual noise, or is blowing weak or cool air. Include the service address and affected rooms.
Service is preselectedProvide a phone number or emailPrefer to call? (720) 680-2303
Frequently asked
Furnace Repair questions.
Direct answers for Boulder-area homeowners comparing the next step.
Why is my furnace running but the house is not heating?
The furnace, thermostat, filter, blower, ignition system, ductwork, or another part of the heating system may be involved. The equipment needs to be evaluated to identify the cause.
What causes a furnace to turn on and off repeatedly?
Short cycling can point to a clogged filter, airflow restriction, flame sensor issue, overheating protection, thermostat problem, or an equipment sizing or venting condition. Repeated cycling should be checked before it damages components.
Is a gas smell from the furnace normal?
A brief dusty odor at the start of the heating season can be normal. A gas smell is not. If you smell gas, leave the area, avoid switches and flames, and follow utility or emergency guidance before calling for service.
Should I repair or replace my furnace?
The decision depends on the failed part, equipment age and condition, repair history, efficiency, and installation requirements. Mesa evaluates the system before explaining options.
What should I include in a furnace service request?
Share the address, affected rooms, the main symptom, when it began, any displayed code or sound, and whether the furnace is blowing air at all.
Start with the actual equipment condition.
Call Mesa from 7:00 AM to midnight daily or submit a service request.