Hardwired smoke and co alarms with battery backups give you the most reliable solution for home fire and co poison safety.
We always recommend dual sensor alarms that have both photoelectric and ionization sensors for this reason. They detect both types of fires better. Most alarms have one or the other. Very few have both unfortunately.
Since no one can predict what type of fire might start in their home, the U.S. Fire Administration recommends that every home and place where people sleep have: Both ionization AND photoelectric smoke alarms, OR. Dual-sensor smoke alarms, which contain both ionization and photoelectric smoke sensors.
Mains Wired Alarms Are Best
The only advantages of battery-powered smoke alarms are that they are cheaper, can be installed anywhere (not limited by cable placement) and don't require an Electrician.
As it's unlikely that both the power and battery will fail at the same time, hard wired smoke alarms offer an extremely reliable form of protection. Furthermore, because hardwired smoke alarms are connected to the power supply, they will sound indefinitely until they are turned off.
Can I install a hardwired smoke detector myself? While it is technically possible, it is not recommended. Working with your home's electrical system can be dangerous and complex, best left to a qualified electrician.
Every 10 years
Replace your smoke alarm. Some models last as little as 5 years. This includes battery operated and hard-wired alarms. All smoke alarms have an expiration date.
If your home was built after 1986, it will have at least one hard wired smoke alarm connected directly to your electrical panel. It is not acceptable to replace a hard wired alarm with one that is battery operated.
Test smoke alarms every month by pressing their test buttons. If your alarms use regular batteries, swap in fresh batteries at least once a year. A “chirping” sound means that it's time to change batteries. Because alarm sensors wear out, replace each alarm at least every 10 years.
According to the United States Department of Homeland Security, and the California Building Code, at least one smoke detector needs to be placed in each of the following areas of your home: On Every Floor Level. In Every Bedroom. In Every Hallway Outside of a Bedroom.
Ionization vs photoelectric
An ionization smoke alarm is generally more responsive to flaming fires (imagine a fire where you can see the flame), while a photoelectric smoke alarm is generally more responsive to smoking, smoldering fires (such as a cigarette).
Overall, we recommend the First Alert SA3210 because it combines photoelectric and ionization sensors that detect low and smoky fires as well as high flames. It's also battery-operated, so it's easy to install. If you're looking for a bargain, the Kidde I9030 is a basic smoke detector that does the job at low cost.
Detectors with multiple sensor types (dual-sensor or multicriteria detectors) are typically better at alerting you to both flaming and smoldering fires. Ionization smoke detectors are best at detecting the small particles typical of fast, flaming fires, but they're poor at detecting smoky, smoldering fires.
Even if your home is all electric, it's still recommended that you install carbon monoxide detectors, as CO can seep inside the home from an attached garage or from outside. Texas updated its building codes in 2021 to require all homes built in or after 2022 to install carbon monoxide detectors.
If you want detectors you can depend on that don't run the risk of faulty batteries, then hard wiring them is the way to go. We do suggest having backup batteries in the case of a power outage, but a hardwired smoke or CO alarm will otherwise always be functional and will keep you and your family safe.
Wireless smoke alarm systems must be battery operated. The batteries must be capable of powering normal device operation for one year and have an audible low battery signal. A signal between smoke alarms must be transmitted at least every 200 seconds.
On average, a 9V battery in a smoke detector will last between six months to a year, depending on several factors.
If the electricity in your home goes out, these alarms automatically switch to their secondary power source, the backup battery. The backup battery should power the alarm for a minimum of 7 days without electricity to keep your home protected. Modern hardwired alarms require a battery backup.
In the United States, the Hotel and Motel Fire Safety Act of 1990 states that it is a legal requirement for hotels and motels to have 'hard-wired, single-station smoke detectors in each guestroom in accordance with the National Fire Protection Association (NFPA) standard 72'.
The Kidde Hardwired Smoke Alarm with Indoor Air Quality Monitor doesn't have as many features as the Google Nest Protect, but it still works well, and it's a much less expensive way to improve your smoke alarm system.
Why did my fire alarm randomly go off in the middle of the night? This is likely due to one of the common causes like low battery, dirt buildup, humidity, or insects interfering with the sensor.
With hardwired smoke detectors, they can be connected together so that if one goes off, they all are triggered. This interconnection can save precious minutes if a fire occurs in an area of your house and has a chance to spread before you are fully aware.