You buy your own they are battery operated.

If you get them done professionally you can have them hard wired to your houses electricity supply witha battery backup.

Personally, if i had the choice, I would have straight battery ones. The hardwires ones we have eat electricity whereas 1 battery a year roughly is much cheaper.


WHEN YOU CHANGE YOUR CLOCKS FOR DLS, CHANGE YOUR SMOKE ALARM BATTERY!!! ;o)
(Public Service Announcement lol)


Oh, and if you are building your house new it is law (in WA at least) that your smoke detectors be hardwired and professionally installed, with minimum number requirements based on sq meterage of your home.

HTH