3 ms·

My alarms are connected to the house power -- no batteries. That seems like the best way. Perhaps battery for power failures.

• cbhl 13y ago
  The failure mode of that is when the fire is electrical in nature, and causes house power to fail before the alarms notice.
  • a-priori 13y ago
    Yes, all such devices will have battery backups. You should use them for just that situation.