Home Safety & Fire Safety · 7 min read · Beginner

Smoke, Heat & Carbon Monoxide Alarms Explained

Understand the different jobs smoke, heat and carbon-monoxide alarms do, why they are not interchangeable and what to check before buying.

Key points & steps

Smoke alarms detect products of combustion/smoke and provide early warning of fire; use an alarm type suitable for the intended location.
Heat alarms respond to temperature rather than smoke and are commonly used where normal cooking fumes could make a smoke alarm unsuitable.
Carbon monoxide alarms detect CO, an invisible poisonous gas produced by incomplete combustion. They do not detect smoke or replace fire alarms.
Check the relevant British/European standard marking, product lifetime, power source and whether interlinking is required for your home or tenancy type.
Position and install every alarm according to its manufacturer instructions and any legal requirements applying to the property.
Test alarms regularly as instructed, keep them unobstructed and replace units at the end of their stated service life.

Scotland has a statutory interlinked smoke/heat alarm standard for all homes; rental rules in the other UK nations differ.
Specialist vibrating/flashing alert systems may be needed for people who are deaf or hard of hearing.
Do not rely on a colour-change CO indicator in place of a proper audible certified alarm.