Carbon Monoxide Safety at Home: Alarm Placement, Symptoms, Generators and Heating Season Rules • Living Life as Moms | Mom Hacks, Toddler Snacks, and Kids Activities

Quick answer: carbon monoxide (CO) is an invisible, odorless gas produced by burning fuel, and it can poison a family without warning. Install CO alarms on every level of your home and outside each sleeping area, test them monthly and replace them as the manufacturer directs. Never run a generator, charcoal grill, camp stove or car inside a home or garage, keep fuel-burning appliances and chimneys inspected, and know the symptoms: headache, dizziness, weakness, nausea and confusion. If an alarm sounds or anyone feels sick, get everyone outside to fresh air and call 911. Poison Control is available at 1-800-222-1222.

Heating season brings cozy evenings and a quieter risk. Furnaces, fireplaces, space heaters, water heaters and stoves all burn fuel, and when something goes wrong they can release carbon monoxide into the air your family breathes. You cannot see it, smell it or taste it.

The encouraging news is that CO poisoning is largely preventable with a few inexpensive steps. This guide covers the essentials, from alarm placement to what to do in a power outage. It is part of our family health and safety guide and works alongside our winter home safety tips and home fire safety checklist.

Sources: U.S. Consumer Product Safety Commission (CPSC) carbon monoxide information center and generator safety guidance; Centers for Disease Control and Prevention (CDC) carbon monoxide poisoning prevention pages; National Fire Protection Association (NFPA) carbon monoxide safety tips; U.S. Fire Administration home heating safety information; Poison Control (poison.org and 1-800-222-1222). Follow your alarm’s instructions and local codes. Checked November 2026. This article is general safety information, not medical advice.

What Carbon Monoxide Is

Carbon monoxide is a gas produced whenever fuel such as natural gas, propane, gasoline, oil, wood or charcoal burns incompletely. Appliances that are working properly and vented to the outdoors produce small amounts that escape safely. Trouble starts when a furnace is faulty, a flue or chimney is blocked, a generator runs in an enclosed space or a car idles in an attached garage.

When you breathe CO, it enters the blood and replaces oxygen. At high levels it can cause unconsciousness and death in minutes. According to the CDC, people who are sleeping or intoxicated can die from CO poisoning before they ever notice symptoms.

Who is most at risk

The CDC notes that unborn babies, infants, older adults and people with chronic heart disease, anemia or breathing problems are more likely to get sick from CO. Children are smaller and breathe faster, so keep them in mind when checking your home, but everyone in the house is at risk when levels rise.

Common Sources in a Family Home

Gas or oil furnaces and boilers
Gas water heaters and clothes dryers
Gas stoves and ovens
Fireplaces and wood stoves
Portable generators and gas-powered tools
Charcoal and gas grills and camp stoves
Vehicles running in attached garages
Space heaters that burn fuel such as kerosene
Blocked chimneys, flues and vents

Electric appliances do not produce carbon monoxide, but homes with any fuel-burning equipment, an attached garage or a fireplace should have alarms.

Symptoms to Know

Early symptoms of CO poisoning are often described as flu-like, but without a fever. The CDC lists:

Headache
Dizziness
Weakness
Upset stomach or vomiting
Chest pain
Confusion

A big clue is the pattern. If several people in the household feel sick at the same time, if symptoms improve when you leave the house and return when you come back or if pets seem ill, think of carbon monoxide. Babies and young children may be unusually fussy, sleepy or may not feed well, and they cannot tell you what is wrong.

If you suspect CO poisoning, leave the building right away and call 911. Do not stop to open windows or investigate first.

Where to Put Carbon Monoxide Alarms

Smoke alarms do not detect carbon monoxide, although some alarms combine both functions. The NFPA and CPSC recommend CO alarms:

On every level of the home, including the basement.
Outside each separate sleeping area, close enough that the alarm can wake you.
Near an attached garage, following the manufacturer’s directions.

Do not place an alarm directly beside a fuel-burning appliance, in a very humid spot or in a dead-air corner, since that can trigger false alarms or reduce accuracy. Read the packaging for specific height and distance rules. Unlike smoke, CO mixes with the air, and many alarm makers allow installation at any height.

Choosing alarms

Look for a label from a recognized testing laboratory such as UL or an equivalent.
Choose battery-powered alarms or plug-in alarms with battery backup so they still work in a power outage.
Consider a model with a digital display, which can show CO levels.
Interconnected alarms sound throughout the house, which helps families with heavy sleepers.

Testing and replacing

Test every month by pressing the test button.
Replace batteries on the schedule the manufacturer gives, or when the unit chirps.
Replace the alarm itself when it reaches its end of life. Many alarms need replacement every 5 to 10 years, and many have an end-of-life signal. Check the date printed on the back.
Never remove the batteries because of a nuisance alarm. Learn what the signals mean instead.

Write the installation date on each unit with a marker so you know when to replace it. Our checklist on home fire safety suggests a similar monthly routine for smoke alarms, so you can test both on the same day.

Heating Season Checklist

Before the cold settles in, take these steps.

Have your heating system inspected every year by a qualified professional. This includes the furnace, boiler, vents and flue.
Have chimneys and flues cleaned and checked each year if you use a fireplace or wood stove.
Keep vents clear. Snow, ice, leaves and nests can block exhaust vents for furnaces, water heaters and dryers. After heavy snow, clear them by hand.
Check that pilot lights and flames look right. A steady blue flame is normal for most gas appliances, while a yellow or orange flame can indicate a problem. Call a professional if you see one.
Do not use a gas oven or stove to heat your home. They are not designed for that purpose.
Never burn charcoal indoors, even in a fireplace or a garage.
Use fuel-burning space heaters only if they are made for indoor use, have adequate ventilation and follow the manufacturer’s directions. Keep children away from any heater.

Generators, Grills and Garages

Most deadly cases happen in or near homes when people run equipment that is meant for outdoor use.

Generators: Run portable generators outdoors, far from windows, doors and vents. The CPSC advises keeping them at least 20 feet from the house with the exhaust pointed away. Do not run one in a garage, even with the door open, or in a basement or crawlspace. Install battery-powered or battery backup CO alarms before a storm hits.
Grills and camp stoves: Use them outside only, and never in a tent, camper, garage or on a porch that is enclosed.
Cars: Do not start a car in an attached garage, even with the garage door open. Back the vehicle out before you let it warm up. In snow, check that the tailpipe is not blocked.
Gas-powered tools: Pressure washers and other engines produce CO. Keep them outdoors in open air.

During a Power Outage or Storm

Outages create the highest-risk conditions because families look for alternative ways to heat and cook.

Use flashlights, not candles, for light when possible, and keep fire safety in mind.
Do not use a generator inside or near an open window.
Do not use a charcoal grill or camp stove indoors.
Move to a safe warm location such as a shelter, library or relative’s home if the house gets too cold.
Keep your phone charged and know how to reach emergency services.

What to Do If an Alarm Sounds

Do not ignore it. Treat every alarm as real until proven otherwise.
Get everyone outside into fresh air right away, including pets if you can do so safely.
Call 911 from outside or from a neighbor’s home.
Count heads. Make sure everyone is out.
Do not go back in until the fire department or utility says the home is safe.
Get medical attention for anyone with symptoms, even if they feel better after getting outside.
Have appliances inspected and repaired before you use them again.

Poison Control (1-800-222-1222) provides free, confidential advice around the clock if you have questions, and our guide to poison prevention at home lists other times to call.

A Room-by-Room Walk-Through

Take ten minutes this weekend to walk through the house with a notepad.

Basement or utility room. Look at the furnace, water heater and dryer vent. Check that nothing is stored against the equipment and that exhaust pipes are connected. Make sure an alarm is on this level.
Kitchen. Confirm the range hood vents outdoors if it is designed to, and that burners light with a steady blue flame. Keep the oven for cooking only.
Living room. If you have a fireplace, make sure the damper is open before a fire and that the chimney was inspected this year. Keep a screen in place around children.
Hallways near bedrooms. Make sure there is an alarm within hearing distance of every sleeping area, and test it while you are there.
Garage. Check that the door to the house seals properly, and never let engines idle inside. Store gas cans and equipment according to local rules.
Outside. Walk around the foundation. Look for snow or debris blocking furnace, dryer and water heater vents, and for any soot staining around them.

Apartments, Rentals and Travel

Families in apartments and rentals are not exempt. Many places require alarms, but compliance varies, so check yours.

Ask your landlord whether CO alarms are installed, who maintains them and when the heating system was last serviced. Put the request in writing.
Buy your own battery alarm if needed. They are inexpensive and portable.
Pack one when you travel. A small battery-powered alarm can go in a suitcase for holiday trips, cabins and vacation rentals, where fuel-burning heaters and fireplaces are common.
Never use grills or camp stoves in a cabin, tent or camper for warmth or cooking.

What About False Alarms?

A chirp is not always a CO event, but do not assume it is a mistake.

A single short chirp every minute usually means a low battery.
Five chirps every minute can mean the alarm has reached its end of life, depending on the model.
A continuous loud pattern means CO has been detected. Leave and call 911.

If an alarm keeps going off after the fire department says the home is safe, have a qualified technician check your appliances. Replace the alarm only when you know why it is alarming.

Practice a Plan

Include carbon monoxide in your family emergency plan.

Teach older children what the alarm sounds like and that they should go outside, not hide or look for the source.
Practice leaving the house at night.
Choose a meeting place outside, such as the mailbox or a neighbor’s porch.
Keep emergency numbers where children can find them, and teach them how to call 911.
Show babysitters and visitors where the alarms are and what to do.

Frequently Asked Questions

Do I need a CO alarm if my home is all electric?

If you have no fuel-burning appliances, no fireplace and no attached garage, the risk is low, but an alarm is still inexpensive. Check local requirements, which may apply to rentals.

How often should I replace carbon monoxide alarms?

Follow the manufacturer’s instructions. Many units need replacement every 5 to 10 years, and many signal when they reach the end of life.

Can carbon monoxide poisoning be mistaken for the flu?

Yes. The symptoms are similar, except there is no fever. If several people feel sick together or feel better away from home, get outside and call 911.

Can I open windows to clear the air instead of leaving?

No. When an alarm sounds or someone has symptoms, leave first and call for help from outside.

Is a smoke alarm enough?

No. Smoke alarms do not detect carbon monoxide unless they are specifically combination alarms.

The Bottom Line

Carbon monoxide is dangerous because you cannot sense it, but the prevention steps are simple. Put working CO alarms on every level and outside sleeping areas, test them each month, have fuel-burning appliances inspected every year, keep generators, grills and cars out of enclosed spaces and teach your family to leave the house if an alarm sounds. A few minutes spent on these steps before the cold arrives can protect everyone under your roof.