Daylight saving time ends at 2 a.m. Sunday, Nov. 1, and most Americans will turn their clocks back an hour this weekend. Fire and health officials have long tied that ritual to another one: test your smoke alarms and carbon monoxide (CO) alarms. With furnaces, fireplaces and space heaters coming back on across much of the country, the timing matters. Here is what the National Fire Protection Association (NFPA), the U.S. Fire Administration, the Consumer Product Safety Commission (CPSC), the CDC and the American Red Cross say about testing, replacing and placing the alarms that protect your home.
Why it matters: the numbers
Working alarms make a measurable difference. According to the NFPA:
- Roughly three out of five home fire deaths happen in homes with no smoke alarms or no working smoke alarms.
- More than one-third (38%) of home fire deaths result from fires in which no smoke alarms are present.
- The risk of dying in a home fire is cut in half in homes with working smoke alarms.
- In a fire, you may have as little as two minutes to escape safely.
The American Red Cross says on its Sound the Alarm page that home fires claim seven lives every day in the U.S.
The CO numbers are just as sobering. The CDC says that each year more than 400 Americans die from unintentional CO poisoning not linked to fires, more than 100,000 visit an emergency department and more than 14,000 are hospitalized. CO is odorless and colorless, and the CDC warns that people who are sleeping can die from it before they ever feel symptoms.
Many homes have alarms that do not work
Having alarms on the ceiling is not the same as being protected. In 2024, the CPSC released a national survey on smoke and CO alarms in which researchers actually tested alarms in homes. The full report estimated that about 99% of U.S. households have smoke alarms, but almost half are missing CO alarms. It also estimated that 16% of households had no functional alarms at all – mostly because the alarms they had did not work (15%), rather than because they had none (1%).
The same report found that people knew how many alarms they had and where they were, but were less accurate about how the alarms worked and how old they were – which matters, because alarms wear out.
How to test your smoke alarms
Testing takes a few minutes.
- Warn the household. Alarms are loud. Let everyone, including kids and pets, know what is about to happen.
- Press and hold the test button. The NFPA says you should hear a loud “beep, beep, beep.” That means the alarm’s horn and battery are working.
- Test every alarm, on every level, including the basement.
- No sound or a weak sound? Replace the battery and test again. If it still fails, or the alarm is more than 10 years old, replace the whole unit.
- Check interconnection. If your alarms are interconnected, all of them should sound when you test one.
- Clean them. Follow the manufacturer’s instructions; dust and cobwebs can interfere with the sensor.
The NFPA and the U.S. Fire Administration both say to test smoke alarms at least once a month – not just twice a year. The clock change is a good reminder to do the bigger jobs: batteries, expiration dates and adding missing alarms.
Know the sounds
The NFPA explains what your alarm is telling you:
- Three loud beeps in a row, repeated: smoke or fire. Get out, call 911 and stay out.
- A single chirp every 30 or 60 seconds: the battery is low and must be changed.
- Chirping that continues after a new battery: the alarm has reached the end of its life and must be replaced.
CO alarms use different sound patterns that vary by brand. Look up your model’s manual so everyone knows the difference.
Batteries, 10-year alarms and replacement age
What you need to do depends on the type of alarm. The U.S. Fire Administration gives these general rules:
- Alarms with a 9-volt battery: test monthly, replace the battery at least once a year and replace the entire alarm every 10 years.
- Alarms with a sealed 10-year lithium (“long-life”) battery: test monthly and replace the entire alarm according to the manufacturer’s instructions.
- Hardwired alarms: test monthly, replace the backup battery at least once a year and replace the entire alarm every 10 years.
Smoke alarms must be replaced 10 years after the date of manufacture, not the date you installed them, according to the NFPA. The date is usually printed on the back of the unit. The Red Cross notes that the sensor becomes less sensitive over time.
CO alarms have their own lifespan. The CDC says to replace a CO detector following the manufacturer’s instructions or every five years, and to check its batteries when you change your clocks each spring and fall.
Where to put smoke and CO alarms
Smoke alarms. The NFPA recommends:
- Inside every bedroom and outside each separate sleeping area, such as a hallway.
- On every level of the home, including the basement.
- On the ceiling or high on a wall.
- At least 10 feet from the stove to reduce nuisance alarms – and not in kitchens or bathrooms.
Only qualified electricians should install hardwired smoke alarms, the NFPA says.
CO alarms. The U.S. Fire Administration’s carbon monoxide guidance says to install CO alarms in a central location outside each separate sleeping area and on every level of the home. The CDC recommends battery-operated or battery backup CO detectors near every sleeping area, which keeps you protected during a power outage. If you have a fuel-burning furnace, water heater, stove, fireplace or attached garage, CO alarms are especially important.
Always follow the manufacturer’s placement instructions, and check your state and local rules: many places have their own requirements for smoke and CO alarms, especially in rental housing and when a home is sold.
Which alarms to buy
There are two main kinds of smoke sensors. The NFPA says ionization alarms respond faster to flaming fires and photoelectric alarms respond faster to smoldering fires. The U.S. Fire Administration recommends having both kinds in the home, or dual-sensor alarms that include both.
Other tips from the NFPA and USFA:
- Buy listed alarms. Look for a mark from a nationally recognized testing laboratory.
- Choose interconnected alarms, so when one sounds, they all sound. Many newer wireless models can interconnect without new wiring.
- Consider “multi-criteria” alarms that say they help reduce cooking nuisance alarms. The NFPA suggests them when it is time to replace older units.
- Combination smoke/CO units cover both hazards in one device. Make sure each location still meets the placement advice for both.
- For people who are deaf or hard of hearing, there are alarms with strobe lights and bed or pillow shakers.
Never disable a smoke alarm because of cooking smoke. The U.S. Fire Administration says removing the battery “can be a deadly mistake.” Open a window, fan the air or move the alarm farther from the kitchen.
Heating season: the CO and fire risks rising now
Heating is a major source of home fires. The U.S. Fire Administration’s heating fire safety page says an estimated 32,200 home heating fires in 2021 caused about 190 deaths, 625 injuries and $442 million in property loss. Portable heaters were only 3% of home heating fires in 2017-2019 but accounted for 41% of fatal ones.
The CDC’s CO prevention advice for this time of year:
- Have your heating system, water heater and other gas-, oil- or coal-burning appliances serviced by a qualified technician every year.
- Have your chimney checked or cleaned every year.
- Never heat your home with a gas oven.
- Never use a generator inside the home or garage, even with doors and windows open; keep it more than 20 feet from windows, doors and vents.
- Never run a car in an attached garage, even with the garage door open.
For more detail, see UVN’s guides to space heater safety, fireplace safety and winter power outage preparedness.
If a CO alarm goes off
The CDC says CO poisoning symptoms are often described as “flu-like”: headache, dizziness, weakness, upset stomach, vomiting, chest pain and confusion. If your CO alarm sounds, get everyone – including pets – outside into fresh air right away and call 911. Do not go back inside until emergency responders say it is safe. Then have a qualified technician find and fix the source.
Free help and a two-minute plan
Alarms only help if everyone can get out. The NFPA’s escape planning guidance calls for marking two ways out of every room, choosing an outside meeting place and practicing the plan twice a year. If you cannot afford alarms or cannot install them yourself, the Red Cross’s Sound the Alarm program installs free smoke alarms through local events, and many fire departments run their own programs. Call your local fire department’s non-emergency line to ask.
Your weekend checklist
Before you go to bed Saturday or once your clocks are changed Sunday:
- Press the test button on every smoke and CO alarm.
- Replace 9-volt and backup batteries.
- Check manufacture dates: replace smoke alarms 10 years or older and CO alarms that have passed their replacement date.
- Add missing alarms in bedrooms, hallways and on every level.
- Schedule a furnace and chimney check if you have not had one this year.
- Set a monthly phone reminder to test your smoke alarms.
The bottom line
The clocks fall back this weekend, and heating season is here. It takes about 10 minutes to test your smoke alarms and CO alarms, replace a few batteries and check dates. With working smoke alarms cutting the risk of dying in a home fire in half, and CO alarms missing in almost half of U.S. homes, those 10 minutes may be the most important home safety job of the year.
