Checking Your Smoke and Carbon Monoxide Detectors

As home inspectors, we’ve seen too many homes where smoke and carbon monoxide (CO) detectors are either missing, outdated, or not functioning properly. These small devices serve as the first line of defense against two of the biggest household dangers—fire and carbon monoxide poisoning. However, many homeowners neglect their detectors and assume they’re working just because they’re installed. The reality is that these detectors require regular maintenance, testing, and correct placement to be effective.

Why Smoke and Carbon Monoxide Detectors Matter

Smoke Detectors: Your First Defense Against Fire

Smoke detectors are critical for early fire detection. According to a study by the National Fire Protection Association (NFPA), three out of five home fire deaths occur in homes without working smoke alarms. Additionally, one in five houses with smoke detectors had at least one functionality problem with their alarm.

Carbon Monoxide Detectors: Protecting Against the Silent Killer

Carbon monoxide is a colorless, odorless gas that can be fatal if inhaled in high concentrations. It’s produced by fuel-burning appliances like furnaces, stoves, water heaters, and fireplaces. Without a CO detector, you may not realize there’s a problem until symptoms like headaches, dizziness, or nausea set in—which may be too late.

Common Detector Mistakes Homeowners Make

During home inspections, we often encounter these issues:

1. Missing or Dead Batteries – A non-functioning detector is useless. Many homeowners remove batteries due to false alarms and forget to replace them.
2. Outdated Units – Smoke detectors have a lifespan of about 10 years, while CO detectors typically last 5-7 years. Dual detectors can have a different life expectancy, so always refer to your device’s needs. If yours is older, it’s probably time to replace them.
3. Poor Placement – Both smoke and CO detectors should be placed near sleeping areas and on every level of your home. Don’t place either detector right next to or over a fireplace or flame-producing appliance. Many experts recommend placing your CO detector in the “breathing zone”, but check your model’s specific instructions.
4. Lack of Interconnected Alarms – Modern detectors can interconnect so that when one alarm sounds, they all go off, providing maximum warning time.
5. Failure to Test – You should test both smoke and CO detectors monthly using the “test” button and replace the batteries at least once a year.

Home Inspector Tips for Smoke and CO Detector Safety

• Check the Manufacture Date – Look for the manufacture date on the back of the unit. If it’s close to expiring, replace it.
• Upgrade to Combination Alarms – Some models detect both smoke and carbon monoxide, reducing the number of devices you need.
• Install CO Detectors at the Right Height – Unlike smoke, which rises, CO is roughly the same weight as air, so you should place detectors at eye level or lower.
• Use Hardwired or Battery Backup Models – Hardwired detectors with battery backups provide the best reliability.
• Don’t Ignore Alarms – If your CO detector sounds, leave your home immediately and call emergency services.

The Bottom Line

Smoke and carbon monoxide detectors are simple devices that can save lives. However, they only help if they are properly installed and maintained. As home inspectors, we urge every homeowner to take their safety seriously by regularly testing and replacing these critical alarms. Don’t wait for an emergency to find out your detectors aren’t working—check them today!