Testing Your Smoke & CO Alarms (and When to Replace Them)
- Just Better Home Services
- Oct 8
- 4 min read
Smoke and carbon monoxide (CO) alarms are the first line of defense in protecting your family from hidden dangers. But too often, these devices are forgotten once they’re installed—left untested, with expired batteries, or well past their replacement dates.
At JBHS, we want every Virginia homeowner to feel confident that their alarms will work when it matters most. Let’s cover how to test your smoke and CO alarms, when to replace them, and why having a professional install hardwired, interconnected alarms is one of the smartest upgrades you can make.
In this article:
Why Testing Your Alarms Matters
According to the National Fire Protection Association (NFPA), working smoke alarms cut the risk of dying in a house fire by half. A smoke alarm’s warning can cut the risk of dying from a fire in your home by almost half.) CO detectors are just as critical, since carbon monoxide is odorless and colorless—often called the “silent killer.”
Testing your alarms ensures:
Batteries are still powering the device.
The alarm sounds properly when triggered.
You and your family recognize the sound and can respond quickly.
How Often to Test Smoke & CO Alarms
It’s easy to assume that once installed, smoke and carbon monoxide alarms will always work. Unfortunately, dust buildup, dead batteries, or simple wear-and-tear can cause an alarm to fail without you realizing it. That’s why regular testing is essential.
Here’s what experts recommend—and why:
Monthly Testing: Press and hold the “test” button until you hear the alarm sound. This confirms that the internal electronics and speaker are working. Even brand-new alarms can be defective, so monthly testing ensures you’ll catch a problem before an emergency occurs.
Battery Changes (Once a Year or As Needed): If your alarm uses replaceable 9-volt batteries, they should be changed at least once a year. Test smoke alarms every month and replace 9-volt smoke alarm batteries at least once every year. A weak battery can prevent the alarm from sounding—or worse, cause it to chirp at night and tempt homeowners to remove it altogether. Some newer alarms come with sealed 10-year batteries, which eliminate yearly changes but still require monthly tests.
After Power Outages: For hardwired alarms, test them after your home loses power. Power surges or outages can sometimes reset or damage the system. A quick test ensures your alarms are still functioning properly once electricity is restored.
Seasonal Checks: Many fire safety professionals recommend pairing alarm tests with other household routines, such as changing HVAC filters or adjusting for daylight saving time. This makes testing easy to remember and part of your regular home maintenance.
Testing is about more than compliance—it’s about confidence. A few seconds each month ensures that when seconds matter most, your alarms will do their job.
When to Replace Smoke & CO Alarms
Even if your alarms still beep during a test, that doesn’t mean they’ll function properly in an emergency. Just like any piece of technology, smoke and carbon monoxide detectors have a limited lifespan. Over time, their sensors become less sensitive, dust and debris can clog internal parts, and electronic components wear out.
Here’s what you need to know:
Smoke Alarms - Replace Every 10 Years: Most manufacturers and the NFPA recommend replacing smoke alarms every 10 years. After a decade, the sensors may not detect smoke particles quickly enough, even if the alarm still seems operational
Carbon Monoxide Detectors - Replace Every 5–7 Years: CO sensors degrade faster than smoke sensors. After 5–7 years, they may no longer detect dangerous CO levels in time to warn you. Always check your manufacturer’s guidelines, as lifespans vary by brand.
Combination Units - Follow the Shorter Timeline: If you have a device that combines smoke and CO detection, use the replacement schedule for the shorter lifespan (often the CO component at 5–7 years).
Check the Manufacture Date: Look at the back of your alarm for a stamped or printed date. If it’s more than a decade old for smoke alarms—or more than 7 years old for CO detectors—it’s time for a replacement, even if it still chirps during tests.
Why replacement matters: A worn-out detector might give you a false sense of security. Fires today burn hotter and faster due to modern materials, giving families less time to escape. Fresh, reliable detectors can be the difference between safe evacuation and tragedy.
Battery-Powered vs. Hardwired Detectors
Most homes have a mix of battery-powered and hardwired detectors. But for maximum safety:
Battery-powered alarms work independently, but if one dies, others won’t alert you.
Hardwired, interconnected alarms trigger all alarms at once—so if smoke is detected in the basement, the alarm will sound upstairs too.
This provides whole-home protection and ensures you’ll hear the alarm no matter where you are.
Why Professional Installation Matters
Installing hardwired alarms isn’t a DIY project—it requires running new wiring, connecting to your home’s electrical system, and ensuring the alarms are properly placed.
A licensed JBHS electrician can:
Safely install hardwired, interconnected smoke and CO alarms.
Ensure alarms are placed in every required location (bedrooms, hallways, basements).
Verify your electrical system is up to code and safe.
Show you how to test and maintain your alarms.
Professional installation gives you peace of mind that your alarms will work when seconds count.
At JBHS, we do more than plumbing, HVAC, and electrical—we help keep families safe. Our electricians specialize in:
Installing hardwired smoke & CO alarms.
Replacing outdated detectors with modern, reliable models.
Testing your electrical system to ensure safe connections.
Offering advice on alarm placement and maintenance.
Working smoke and CO alarms are non-negotiable for a safe home. Testing them monthly and replacing them on schedule saves lives—but upgrading to hardwired, interconnected detectors offers the most reliable protection.
If you’re ready to replace old alarms or upgrade your home’s safety system, don’t leave it to chance. Protect your home today, for peace of mind tomorrow.