Heating

Carbon Monoxide Alarms: A Homeowner’s Check for Heating Season

Learn where CPSC says to place carbon monoxide alarms, how to check them, and what to do if one sounds near your home heating equipment.

October 12, 2026 · 3 min read

Place battery-operated carbon monoxide alarms, or alarms with battery backup, on every level of your home and outside sleeping areas. Follow the manufacturer’s instructions for testing and maintaining your alarm; CPSC does not specify a testing interval in the cited guidance. If an alarm sounds, leave immediately, call 911 or emergency services from outside, and do not re-enter until responders say it is safe. A heating-system inspection is not a substitute for this emergency response.

Why a working CO alarm belongs in a heating-season check

Carbon monoxide (CO) is odorless and colorless, so you cannot rely on smell or sight to detect it. The Consumer Product Safety Commission (CPSC) recommends that home heating systems, including chimneys and vents, be inspected and serviced annually by a trained service technician. A working alarm is an additional household safeguard; CPSC cautions that alarms do not replace proper use and upkeep of appliances that can produce CO.

This check is about alarms and emergency readiness, not diagnosing a furnace or other appliance. For homeowners in southeastern Pennsylvania, the same basic alarm guidance applies whether the home is in Bucks County, Montgomery County, or Philadelphia.

Check alarm coverage around sleeping areas and on every level

CPSC recommends installing battery-operated CO alarms, or alarms with battery backup, on every level of the home and outside sleeping areas. Its guidance also says to follow the alarm manufacturer’s instructions. Use those instructions when checking placement and installation; do not assume that one alarm in a different part of the home provides the coverage CPSC describes.

CPSC says interconnected alarms are best because when one sounds, they all sound. If you are unsure whether your alarms are interconnected or whether the home has the recommended coverage, check the product instructions or contact a qualified professional for help. Do not treat an alarm’s presence as proof that heating equipment is operating safely.

Test alarms according to the product instructions

CPSC advises consumers to follow the manufacturer’s instructions when testing a CO alarm. It explains that using a test button checks whether the circuitry is operating correctly; it does not establish the accuracy of the sensor. A successful button test is useful, but it is not a measurement of CO levels or a substitute for professional equipment inspection.

Check the alarm instructions for testing, battery care, and other maintenance directions, and follow them for your specific device. CPSC guidance calls for battery-operated alarms or models with battery backup. If an alarm does not respond as expected during a test, follow the manufacturer’s instructions and do not rely on that alarm as working protection.

If a CO alarm sounds, leave first

Treat an alarm signal as a potential emergency. CPSC says not to try to find the source of CO. Move everyone outside to fresh air immediately, then call 911, the fire department, or emergency services from outside. Do not go back inside until emergency responders give permission. Do not substitute a call to an HVAC contractor for this emergency response.

If responders determine that a malfunctioning appliance is the source, CPSC says not to operate it until it has been properly serviced by trained personnel. If authorities allow you to return and the alarm activates again within 24 hours, CPSC says to repeat the evacuation and emergency-call steps, then call a qualified appliance technician to investigate. Follow responders’ directions and do not try to inspect or repair fuel-burning equipment yourself.

Keep emergency steps separate from routine heating service

CPSC recommends annual inspection and service of home heating systems, including chimneys and vents, by a trained service technician. That is routine prevention; it does not change what to do when an alarm sounds. An alarm event requires immediate evacuation and emergency services first. Only after responders have cleared the home should any follow-up appliance investigation or service take place.

A practical household plan can be simple: know where the alarms are and use their instructions to test and maintain them. Make sure everyone knows to leave if one signals. Keep the emergency response clear: get outside, call for help, and wait for official clearance before re-entering.

Common questions

Where should carbon monoxide alarms be installed?

CPSC recommends battery-operated CO alarms or alarms with battery backup on every level of the home and outside sleeping areas. Follow the manufacturer’s instructions for your specific alarm’s installation and placement.

How often should I test a carbon monoxide alarm?

CPSC says to follow the manufacturer’s instructions for testing; the cited guidance does not specify a testing interval. CPSC notes that a test button checks whether the circuitry is operating correctly, not the accuracy of the sensor.

What should I do if a carbon monoxide alarm sounds?

Do not try to find the CO source. Immediately move everyone outside to fresh air and call 911, the fire department, or emergency services from outside. Do not re-enter until emergency responders give permission. An HVAC service call is not a substitute for this emergency response.

Does an annual heating-system inspection replace CO alarms?

No. CPSC recommends annual inspection and service of home heating systems by a trained technician, and separately recommends CO alarms on every level and outside sleeping areas. These are distinct safeguards; an inspection does not replace an alarm or emergency action.