How Long Until Smoke Detectors Expire? Know Best Time to Replace Smoke Detectors

A person once said that an accident, like fire, is inevitable. Whether in the workplace, hospital, hotel, or home, we will experience unavoidable fire accidents. While such eventualities are unforeseeable, you can control the severity of the outcomes. That’s why you’d need to install a hardwired smoke detector. But How Long Until Smoke Detectors Expire?

According to research by the U.S. National Fire Protection Association (NFPA), property owners should replace all smoke alarms, including the hardwired ones, soon as they are ten years old.

You are also encouraged to replace it sooner, before the ten years, should you notice them responding inadequately when tested.

You may also be wondering, don’t all smoke detectors have batteries? Your thinking is right!

Only that while some smoke detectors exclusively rely on batteries for their workability, hardwired smoke detectors have a battery that would only function if there is a power outage.

The batteries may run out, leading to a severe hazard if not detected earlier and changed. This is precisely why your hardwired smoke detector can expire.

Smoke alarms are crucial as they are life savers. They will detect a fire before it advances by producing a loud and audible sound.

However, just having them in your home or organization is not enough. Ensure that they are working as efficiently as required by replacing them after every decade.

What Are Hardwired Smoke Detectors?

How Long Until Smoke Detectors Expire?
Image of Hardwired Smoke Detector by First Alert

Choosing a smoke detector is a do-or-die affair as it determines your safety and that of your loved ones. Therefore, understanding the different types of smoke detectors is very crucial. 

A hardwired smoke detector is a type of smoke alarm system interconnected to a 120-volt circuit and wired directly into your home’s electrical system. 

Hardwired smoke detectors differ from standard ones because the standard solely depends on battery power. In a hardwired system, all alarms will go off when one is triggered.

Because of this, these alarms will work best in multi-level homes, apartments, buildings, and commercial structures.

Property owners consider the hardwired smoke detectors as the better option than the standard ones since they will only fail in a rare situation where electricity and the battery malfunction.

So, what are the other primary differences between hardwired and battery-powered smoke alarms?

The two types of smoke alarms differ in their maintenance. Maintaining the battery-operated alarms stresses battery replacement. You’ll need to do this regularly to avoid any malfunction.

On the other hand, maintaining the hardwired detectors requires extra effort as it entails more than battery replacement.

Also, it requires you to regularly check the wiring with an expert’s help. Ensure that the power in the main electric panel is turned off before doing any maintenance.

Another difference is in the interconnection. While you can interconnect hardwired alarms, it is impossible to chain more than one battery-operated alarm.

The interconnectedness property in the hardwired alarms is a lifesaver because the detectors will simultaneously alert all the others interconnected to it.

Uses of Hardwired Smoke Detectors

Like the standard smoke detectors we know about, hardwired smoke detectors are a popular home security device used for fire detection. It uses photoelectric or ionization technologies that depend on wiring to function effectively.

The hardwire detectors are available in two different volts; the low and 110 volts. 

The low volts are designed for use in a home security control panel. Its installation entails pre-wiring alongside an alarm system keypad, hardwire contacts, and motion sensors.

It is combined with fire alarm monitoring, which will offer your life and property the best protection.

Caution: Do not remove the 100-volt units in your house once you’ve installed the low-voltage smoke detector, despite them sitting next to each other.

This is because people have different sensitivity and cautiousness when dealing with security issues. Who knows? The next owner of the house might not be as security conscious.

They may not maintain the alarm as expected, thus leading it to a disrepair state. This would expose the home as it will have no fire protection.

Leaving the standard smoke detectors prepares and covers the house against unexpected fire.

Hardwired smoke detectors are available in two types: 2-wire and 4-wire. They describe the number of conductors each detector needs for its functionality.

2-wire smokes receive their power from the same wires they use to sound an alarm. Essentially, they must be connected to an alarm panel that accommodates 2-wire devices.

4-wire smokes will utilize two wires for power and 2 for signaling. Unlike the 2-wire, which can only be used on an alarm panel that supports 2-wire devices, the 4-wire is considered generic.

You can use them with any alarm panel. You are never limited to the number of devices you can connect. This is because power and signals are carried on separate wire pairs.

Smoke detectors, whether hardwired or battery-operated, should be installed at every level of your home or organization. You should also install it in every bedroom to enhance its effectiveness in a fire crisis.

Pros and Cons of Hardwired Smoke Detectors

Having a working and dependable smoke alarm should be a top-tier home safety measure. Fires could come from anywhere, from everyday household items that can spark a fire to environmental risks like wildfire. 

When choosing the best smoke detector to settle for, you must compare the hardwired and battery-operated smoke detectors. They both have their advantages and disadvantages. Let’s analyze them!


  • Secondary power. This is one of the primary advantages of using hardwired smoke detectors over battery-powered models. The hardwired consumes power from two sources. They run on batteries and connect to your property’s electricity. 

This gives it an upper hand over the regular smoke detectors, which require you to constantly change the batteries (so you can’t tell if they will work in case of a fire incident).

Hardwired detectors are a much safer option. You are sure they will operate as long as you have power running. The alarm is, by default, ready to alert you of fire.

If there’s a power outage, then worry not, as you are still covered! The battery will always work as your backup plan. Remember to change and test your batteries as required to avoid malfunctions in times of crisis.

  • Interconnectivity. With hardwired smoke detectors, you can interconnect multiple devices that will uniformly work for your protection.

Typically, standard detectors operate as single units and don’t receive feedback from other smoke detectors in your home. The case is different for the hardwired ones!

When one detector goes off, it alerts every other similar device in the house, thus alerting everyone. This is especially handy when a fire starts in a hard-to-notice place in the house.

  • High Quality-Heat Detectors. Hardwired smoke detectors have built-in heat detectors that would detect the smoke and the heat before the alarms go off.

This is effective, especially when there are false alarms, like a burnt meal in the oven. It makes the device’s functionality even more accurate.

  • They are Easy to Replace. While installing the hardwired smoke detector is challenging, replacing them isn’t a hustle. The process is relatively easy for mildly handy types.

Some manufacturers produce models that are easy to install, especially the kiddle firex smoke detector.

It has a manual that offers easy operation and a front-loading battery door. However, always remember to replace the batteries whenever needed.

Pro tip:  Ensure you’ve installed the hardwire alarms in any rooms with exposed light bulbs.

  • They are more secure than wireless alarm systems.

The alarm panel usually comes with heavy-duty metal housing and a lock design for a hardwired alarm system. This general feature applies to all hardwired systems, including smoke detectors.

They come with a separate key design, giving users access to a hidden alarm panel in the basement.


  • The installation process is one of the most significant issues with hardwired smoke detectors. Installing it is not something you can do as a DIY project. Electricity is dangerous, and mishandling it will lead to consequences as dire as death.

Installing the hardwired detector will consume a lot of your effort. Your electrician must connect it to your home’s power supply through proper wiring.

On the contrary, you can easily install your battery-operated detectors. It would only take you a minute to mount it in the areas you feel comfortable.

How Long Do Hardwired Smoke Detectors Last?

Hardwired smoke detectors will serve you for a reasonably long period than wireless ones. If you are looking for the longest-serving smoke alarm systems, look no further!

The hardwire smoke detectors will serve you for ten solid years of protection. Ten years because you are encouraged to replace your hardwired or battery-operated smoke detector every ten years.

As mentioned earlier, you can replace it if it doesn’t respond as expected when tested, even before the 10-year period elapses.

To check if your alarm system is working, it will be best if you regularly test its functionality. Check your device for the “replace by” dates to know when to replace it.

If it is not indicated, count ten years from when it was manufactured (usually at the back of the device) to get an accurate replacement date.

Important note: While 90% of homes in the U.S. have smoke detectors, 23% of the detectors fail to work.

Why? Dead or missing batteries! Save your family and yourself during a crisis by regularly checking and replacing your batteries after the recommended ten years.

How to Maintain Your Smoke Alarms to Keep Them in Working Condition

  • If you use a battery-operated smoke alarm (nine-volt battery or A.A. battery), test its functionality weekly.
  • Also, clean the alarm monthly since there may be dirt and dust particles which may lead to a malfunction. Cleaning ensures that the smoke can effectively reach the alarm’s sensing chamber.

To clean it, you must gently vacuum the outside of the alarm. To clean it thoroughly, detach it from the power source, then carefully remove the external casing.

Use a household vacuum’s soft brush attachment. A dry piece of cloth will work just as effectively. You can also acquire a can of clean compressed air at the office where you bought your alarm and use it for cleaning.

Caution!! Avoid using water, cleaners, solvents, or air compressor machines to clean your alarm system. Water or excess moisture amount will damage the unit.

  • You will need to replace the batteries annually for the battery-powered smoke detectors. Also, replace the smoke alarm after every decade.
  • If 10-year/long-life batteries power the alarm, you’ll need to test them every once a week. Also, clean the long-life battery smoke detector once a month, as earlier described.
  • Also, a sealed battery is usually irreplaceable; replace the alarm system as soon as you hear five chirps. The chirps usually indicate that your device has maxed out its functionality.
  • Test your hard-wired smoke detector weekly. Like the rest, clean it every once a month.
  • Hardwired detectors also contain batteries as their backup plan; replace them at least once a year. Replace the whole alarm system every ten years.
  • Regularly testing your alarm is an excellent way to ensure they are in good shape. Here is how you can test them:
  • Wear an ear-protective object and then press the test/silence button. Locate this button on the side or top of your unit. You will then hear the test sequence. Also, read your product’s manual for more information on the test sequence. (Different devices work differently, depending on the manufacturer).
  • Most test sequences will be a loud alarm preceded by a warning.
  • If your smoke alarm works through ionization, the test button will put an electric load on the sensing chamber. This will, in turn, cause the alarm to work as if it has detected smoke. This test will also inform you about your battery performance and the rest of the circuit. It also works excellently in testing the sensing chamber.
  • In the case of photoelectric smoke chambers, the test button will cause a reflective material to pop in front of the light-emitting diode (LED). As a result, the light will scatter within the sensing chambers, just like smoke particles would. The test is equally effective for examining the whole unit, not just the battery.
  • In alarms that use carbon monoxide, the test button ensures that the unit receives adequate power from a battery or hardwired device.

Safety Warning: Do not test your alarm using smoke, flames, or exhaust. It is dangerous.

You can also use a UL-certified liquid smoke detector tester to check if your alarms are in the right shape.

How Do You Tell If Your Smoke Detector Is Expired?

If you’ve had the same smoke detectors for decades, it is time to replace them. We have mentioned severally that smoke detectors are designed to last for a ten-year maximum.

After a decade, you will notice that their sensitivity has gone down, thus reducing their ability to sense any smoke. Keeping it in this state equals putting the lives of your loved ones on the line.

Luckily, other signs indicate that your device has maxed out its time and that you need to replace it as soon as possible.

Besides, you don’t want to live with anxiety, wondering whether or not it will function right during a crisis, do you? Below are some of the indicators that your detector needs a replacement.

  • Your smoke detector is changing to yellow

After years of service, old smoke detectors will begin to turn yellow. There are some myths and misconceptions behind this feature.

To some, they turn yellow following constant exposure to dust and the air. Others presume that it is a result of discoloration from cigarette contact.

However, expert research shows that smoke detectors contain bromine, which is used as a flame retardant. Its function is to help the smoke detector withstand fire, thus enabling it to do its ‘alerting’ job about smoke presence.

The bromine component will cause the smoke detector to change to yellow upon exposure to elements like heat, oxygen, and U.V. light.

Therefore, once you notice your device switching to the yellow color, avoid second-guessing by replacing it. It is a clear-cut sign that it is aged and expired.

  • Constant Chirping

If your smoke detector is chirping all the time, respond to it! Do not ignore. If it keeps chirping, it will finally get desensitized, thus reducing its ability to sense any smoke.

If you ignore it, you are also putting your life at risk since the “chirping” indicates that the device is kicking the last kicks of a dying horse.

To solve the chirping, replacing the batteries would be a great option. If it is hardwired, the sound is a significant cause for alarm, and you may need to replace it eventually.

  • Your smoke detector is irresponsive to test

The U.S. Fire Administration encourages property owners to regularly test their smoke detectors’ functionalities. We have outlined the know-how on how to test them.

If your smoke detector is fully functional, expect several beeps upon testing. However, if it doesn’t beep or beeps faintly, then you should be concerned. It can indicate that it has reached its end and needs a replacement.

Research by the U.S. Fire Administration shows that approximately 60% of fire deaths in the U.S. result from homes that lack smoke detectors or have them but do not function. 

Save yourself from being part of these statistics by testing your detectors as regularly as possible.

  • Your Detector Goes Off for No Reason

The smoke detectors will likely lose their sensitivity once they age. Some will begin to go off for no reason. It could be so disturbing that you’ll want to take them down to silence them. It would go off for the slightest reason of dust coming into contact with it.

If your detector behaves like this, replacing it rather than replacing its batteries is best. Replacing them is the only way to ensure that your device only goes off when you need it to.

  • It contains Faulty Parts that Led to a Recall

As part of your maintenance, regularly check to confirm if a recall has been done on your smoke detector. While it may require much effort, it’ll be well deserved.

Occasionally, some smoke detectors are recalled due to faulty parts in them. These faults may cripple their ability to go off during a fire crisis. To find out if yours has any recall,  befriend google and search it up! Do this regularly, as some are recalled at a later date.

Look for any mentioned signs to determine if your device has expired.

 Cost to Replace Hardwired Smoke Alarms

The national average cost for installing a smoke detector ranges between $70-$150. Most people charge about $112 to install a dual hardwired detector.

The installation of a battery-operated smoke detector ranges low in the spectrum. It may cost about $44. A 3-hardwired detector will cost much higher, with some costing as much as $398.

Summarily, a new detector costs between $10-$80. A professional would charge you between $40-$100 per hour, depending on their experience and complexity.

Important Fire Safety Tips to Protect Your Family and Home

  • One of the top tips for fire safety entails installing alarms on every level of your house, from the bedroom to other rooms. Also, test the detectors every month and take appropriate measures should you find them faulty.
  • Discuss with your loved ones a fire escape plan. Also, practice it at least twice a year.
  • Dial the emergency number (9-1-1) to get help whenever necessary.
  • Learn how to use an extinguisher, as it will help you prevent the severity of a fire crisis if it happens.
  • Avoid fighting large fires; you probably lack experience and might get injured. Instead, call the fire department in your zone since they are more experienced and have the necessary equipment to deal with the fire.
  • In case you get burnt to escape, offer first aid by applying cool water on the affected area before help arrives.
  • If you have babysitters, adequately inform them of all preventive measures against fire eventualities. Also, talk to them about your escape plans and what your children need in such an event.
  • Take great care when using flammable liquids. They could easily catch fire.
  • Examine your electrical cords to ensure that they are in a perfect state. If possible, avoid using extension cords and avoid overloading the electrical outlets.
  • Learning CPR is very vital as it is an essential first-aid strategy. It would help you save someone on the brink of death.
  • Avoid smoking in bed or when you are tired, you are tired. You can accidentally drop an unfinished cigarette which may cause a fire.

Note: Find more about home fire safety by checking the safety checklists on approved websites such as the America Red Cross.

How Do You Replace a Hardwired Smoke Detector?

While installing a hardwired smoke detector for the first time may be challenging, replacing it can be a piece of cake.

It is even easier to purchase the replacement from the same manufacturer as you can easily use the same wiring harness. All you need to do is disconnect and install the new alarm. For safety purposes, always turn the power off first.

However, if you cannot access the same unit, purchase a wiring adapter that converts the wiring harness from the initial manufacturer to the current one.

The wiring adapter eliminates the need for fresh wiring. Pop the old harness from your smoke alarm and plug it into your adapter.

Proceed by plugging the adapter into the new smoke alarm. You may need to replace the mounting ring. The ring consists of two simple screws.

Replacing the alarm is as simple as you can ever imagine. You can perfectly do it as a DIY project.

Here’s a Video On How to Replace a Hardwired Smoke Detector:

Final Thoughts

Installing hardwired smoke detectors is crucial for the safety of your home. You are likely to experience fire risks in your daily life; some man-made, while some natural.

While you cannot control some of them happening, you can notice earlier and take the necessary precautions. So,

How Long Until Smoke Detectors Expire

Like everything else with a life limit, smoke detectors also expire with most lasting about 10 years. The U.S. National Fire Protection Association recommends replacing every home’s smoke detector after a decade of installation.

This article has discussed several concepts about a hardwired smoke detector, including other general safety measures to protect your family and home.

Practice some of the safety measures described and test your detector’s efficiency. Let us know in the comment what you think. Enjoy!

Leave a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.