Smoke and carbon monoxide alarms — what should my house have?

Homes on the estate have hardwired, interlinked smoke alarms with battery backup — when one triggers, they all sound, and they keep working in a power cut.

Random beeping or false alarms: persistent unexplained triggering usually means a faulty unit, not something you have to live with — report it to your developer’s customer care and they’ll replace it under warranty. See below for what to check first.

Changing the backup battery

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Most units take a standard 9V battery, and an ordinary alkaline one is fine.

• These alarms are mains-wired, so isolate the lighting circuit at the consumer unit before opening one up.
• Don’t forget the one in the loft. Several house types have an alarm up there, and it’s easy to miss when a chirp seems to be coming from nowhere.

Testing your alarms

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Because they’re interlinked, holding down the test button on any one smoke alarm should trigger all of them to sound — it’s worth testing periodically (monthly is a common recommendation). It’s still worth testing each alarm individually every so often too, in case one has failed silently.

Some homes also have a central test panel on the landing that tests every alarm in the house at once — check whether yours has one.

Carbon monoxide alarms: a CO alarm is required wherever there’s a fixed combustion appliance — for most houses here, that means the room with the boiler. Some homes have combined smoke/CO units fitted and some don’t, so check what you actually have (the label on the unit says). If there’s no CO alarm near your boiler, a standalone battery one costs £15–25 and takes two minutes to fit.