Which Type Of Smoke Alarm Is Best?

We recommend replacing your smoke detectors every 10 years with either a hard-wired detector with a battery back-up (typically 9V) or a 10 year lithium ion detector– in both cases it is highly recommended that the detectors are interconnected (which means they will alarm at the same time.) 10 year lithium ion detectors do not require hard-wiring and have the advantage that they can be placed anywhere – this is an advantage for older homes or upgrades/additions where hard-wiring at the ceiling is not present.

Hard-wired only smoke detectors (older type) – not recommended

Older hard-wired only smoke detectors will only function when there is power- that is a serious draw-back and fire events can cause disruption of power before engulfing homes.  All hard-wired only detectors are now well beyond their expiration of 10 years.

Hard-wired with battery back-up smoke detectors (recent)

The hard-wired with battery back-up smoke detectors should function whether or not there is power and the newer ones offer interconnectivity which means they will all alarm at the same time.  The problem with these detectors is that 30% of them in our country our disabled because they were disconnected or the batteries failed.  The chirping and the frequent battery changing is a nuisance with this type.

10 year Lithium Ion Battery Smoke Detector (newest)

The latest type of smoke detector is the most versatile and needs little maintenance.  10 year lithium ion battery smoke and CO detectors can be placed anywhere, are tamper resistant, and will not need annoying battery changes.  This detector is the most expensive but will save money and may save lives over the long-term.  It should be verified that these detectors offer inter-connectivity (they all will alarm at the same time)

Photo-electric or Ionization?

According to the USFA:

The USFA provides the following guidance to the public and to state and local legislative bodies that may be grappling with the issue of the proper type of smoke alarm to select for use in a residence:

  • We cannot state that one type of alarm is better than another because every fire is different.
  • Because both ionization and photoelectric smoke alarms are better at detecting distinctly different yet potentially fatal fires, and because no one can predict what type of fire might start in a home, the USFA recommends that every home and place where people sleep be equipped with either (a) both ionization and photoelectric smoke alarms, or (b) dual sensor smoke alarms (which contain both ionization and photoelectric smoke sensors).
  • The location of a smoke alarm within a home may be more important than the type of smoke alarm present, depending on the location of a fire. The USFA recommends that users follow the manufacturer’s guidance on the recommended location of smoke alarms in a home.


Smoke/CO detectors should be replaced every 10 years with a hard-wired unit with a back-up battery or a 10 year lithium ion battery – both should offer interconnectivity.  10 year lithium ion batteries are becoming increasingly popular because they cannot be tampered with, the batteries last 10 years and do not need replacing, and the detectors can be placed anywhere regardless of hard wiring.

Also read:  Where should Smoke/CO detectors be placed?

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