Carbon monoxide · heating season

Carbon monoxide alarms for heating season: plug-in, battery or combo

By Shortell Designs · Updated October 2026

Heating season (roughly November through March) is when furnaces, boilers, wood stoves, fireplaces and space heaters run hardest. Carbon monoxide is a colorless, odorless, poisonous gas, and CPSC reports that more than 200 people in the United States die every year from accidental non-fire CO poisoning associated with consumer products. (CPSC)

Compare the six CO alarm picks

Where CO alarms go

Install battery-operated CO alarms, or alarms with battery backup, on every level of the home and outside sleeping areas. Interconnected alarms are best, because when one sounds, they all sound. (CPSC)
Follow the manufacturer's instructions for placement and mounting height, choose an alarm with the label of a recognized testing laboratory, and test CO alarms at least once a month. (NFPA)
During and after a snowstorm, make sure vents for the dryer, furnace, stove and fireplace are clear of snow. (NFPA)
Never run a portable generator inside a home or garage, even with doors and windows open; use it outside only, at least 20 feet from the home with exhaust facing away. (CPSC)
Planning for a winter outage? See our power-outage kit: battery power stations, lanterns and a weather radio.

If the alarm sounds

Move immediately to fresh air outdoors or by an open window or door, make sure everyone is accounted for, and call for help from the fresh-air location. (NFPA) Symptoms include headache, dizziness, weakness, nausea, vomiting, sleepiness and confusion; if you suspect CO poisoning, get outside, then call 911. (CPSC)

An alarm does not replace a chimney or venting inspection

EPA says CO detectors are worth buying as a back-up, but not as a replacement for proper use and maintenance of fuel-burning appliances. EPA advises having furnaces, water heaters, gas ranges, gas dryers, space heaters, fireplaces and wood stoves inspected by a trained professional at the beginning of every heating season, and making certain flues and chimneys are connected, in good condition and not blocked. (EPA) For what an annual chimney inspection covers, see Chimney Sweep Index: inspect every year.

Six CO alarm picks (paid links)

As an Amazon Associate, Shortell Designs earns from qualifying purchases. Links marked (paid link) go to Amazon. We did not test these alarms; facts below come from each Amazon listing.

Plug-in · no battery swaps

Kidde plug-in CO alarm, 10-year battery backup

Plugs into a standard 120V outlet with a 10-year lithium backup for outages. Digital LED display shows the CO level; Peak Level Memory; 85 dB alarm; UL listed, 10-year limited warranty (per the Amazon listing).

Kidde plug-in CO alarm, ASIN B015BRS93Q (paid link)

Battery · wall or tabletop

Kidde 10-year battery CO alarm with display

Electrochemical sensor and a 10-year lithium battery with no wiring. Display updates every 15 seconds; wall or tabletop; green/red/amber LEDs; Peak Level Memory; 85 dB alarm; UL Certified, 10-year limited warranty (per the Amazon listing).

Kidde 10-year battery CO alarm, ASIN B086S53M8K (paid link)

Battery · CO + temperature display

First Alert 10-year battery CO alarm with display

Backlit digital display shows temperature and CO concentration; Peak Level feature; built-in 10-year lithium battery; 85 dB alarm; end-of-life chirp; 10-year limited warranty; tested to meet UL standards (per the Amazon listing).

First Alert 10-year battery CO alarm, ASIN B011O2WW1C (paid link)

Plug-in · display + peak

First Alert plug-in CO alarm with digital display

Plugs into a standard outlet with battery backup; electrochemical sensor; Peak Level feature; 85 dB alarm; end-of-life chirp; 7-year limited warranty (per the Amazon listing).

First Alert plug-in CO alarm with display, ASIN B000Q5VMKG (paid link)

Plug-in · budget extra rooms

First Alert plug-in CO alarm

Plugs into a standard outlet with battery backup; electrochemical sensor; single test/silence button; 85 dB alarm; low-battery signal mute up to 8 hours; end-of-life chirp; 7-year limited warranty (per the Amazon listing).

First Alert plug-in CO alarm, ASIN B000ND74XA (paid link)

Ceiling · smoke + CO combo

First Alert 10-year smoke & CO combo alarm

2-in-1 smoke and CO alarm with Precision Detection sensing to reduce cooking nuisance alarms; 10-year sealed battery; end-of-life warning; slim profile, half the depth of a standard alarm (per the Amazon listing).

First Alert smoke & CO combo alarm, ASIN B0CJMMVST2 (paid link)

As an Amazon Associate, Shortell Designs earns from qualifying purchases. Tag radontestinde-20. An alarm is a back-up, not a replacement for an annual chimney and venting inspection (EPA).