A beeping heat alarm sounds like a beeping smoke alarm, and that is where people go wrong. The two devices watch for completely different things, so the same noise means something different on each.
A heat alarm is a temperature device. It sits in the kitchen, the garage or the boiler house and stays quiet through the burning toast and the steam that would set a smoke alarm off. So when it finally makes a noise, the temperature in that room has changed.
What a heat alarm actually watches
Inside is a thermistor, a sensor whose electrical behaviour changes with temperature. Aico describes heat alarms as reacting to heat and not smoke, giving a warning when there is a substantial increase in temperature. The Ei603 and Ei630i are documented to trigger at around 58°C. Those figures are model-specific, so the manual for the unit on your ceiling is the number that counts.
Aico says heat alarms are intended for kitchens and garages because they resist nuisance alarms from cooking fumes. Building regulations in England and Wales call for one in any kitchen not separated from the circulation space by a door, and Scotland requires one in every kitchen. London Fire Brigade’s advice is blunt: a smoke alarm does not belong there.
A heat alarm is a companion device, not an upgrade. Aico states that its Ei3014 heat alarm can only be used as part of a fire detection system, interconnected with mains smoke or multi-sensor alarms.
Why a heat alarm beeps
There are only three honest explanations.
It got hot. Cooking, an overheating appliance, or a fire. Nothing else activates a heat alarm, and it cannot be fooled by smoke, steam or dust the way a smoke alarm can.
It found a fault. Most heat alarms use short chirps with matching flashes from a fault LED. On a mains unit the commonest cause is a loss of mains power that has drained the backup cell. On a sealed-battery unit the chirp usually means the cell is going flat, which at ten years old means the alarm is finished.
It has reached end of life. Aico documents three short chirps with three fault-LED flashes once a unit passes its tenth year.
| What you hear and see | Most likely cause | What to do |
|---|---|---|
| Loud alarm, red LED flashing rapidly | The sensor has hit its trip temperature | If you cannot name the heat source, get out and call 999 |
| Short chirp on a fixed interval with a fault-LED flash | Power or backup battery problem | Check the consumer unit; on sealed-battery units, replace |
| Two or three chirps with matching fault flashes | Sensor fault, or end of life | Replace the alarm |
| Irregular beeping | Wiring, draughts through the base, electrical interference | Electrician to check the supply, then clean and reseal |
Where heat alarm diagnosis is different
Smoke alarms have a long list of innocent triggers: steam, spray, dust, insects, burnt toast. Heat alarms have none. The only thing that activates them is a real temperature rise at the sensor, which narrows the question to two. Did the room get hot, and why?
- Going off while you cook is a siting problem, not a faulty alarm. Aico advises keeping heat alarms at least one metre horizontally from a sink or cooker. Move the alarm rather than removing it.
- Going off with nothing cooking needs an explanation. Look for a heater, tumble dryer, boiler or vent blowing hot air at the unit, and check for anything electrical that smells hot.
A quiet heat alarm proves nothing
Heat alarms detect heat, not smoke. A fire that smoulders slowly, or one behind a closed door, on another floor, in a chimney or in a wall cavity, may barely warm the air around the sensor. Aico’s limitations section says the alarms will not detect fire if sufficient heat or smoke does not reach them, and that they may not detect every type of fire to give sufficient early warning.
So a silent heat alarm tells you one thing only: that thermistor is not hot. It is not evidence that the building is safe. If you can see smoke, smell burning or feel heat, leave and call 999 whether or not any alarm has sounded.
Where a heat alarm belongs, and where it must never go
| Location | Heat alarm | Smoke or multi-sensor alarm |
|---|---|---|
| Kitchen, not separated from the circulation space by a door | Yes — the intended location | No |
| Garage, boiler house, dusty or fume-heavy areas | Yes | No |
| Hall, landing, corridor, escape route | No | Yes |
| Bedroom | No | Yes |
| Living room | Only where nuisance alarms are very likely and the slower warning is accepted | Yes in most homes |
Two rules follow, and neither has an exception.
Do not swap a smoke alarm for a heat alarm to stop nuisance alarms in a circulation space or a bedroom. Heat alarms are not intended for escape routes or bedrooms, and they respond far too late to protect a sleeping person. In UK rented property the alarm type required there is a legal obligation as well as a safety one. Deal with the cause instead: keep kitchen and bathroom doors shut, move the smoke alarm away from the bathroom door, clean it, or fit a multi-sensor alarm.
Do not fit a heat alarm and leave it standing alone. Interconnect it with the smoke alarms on the escape route, so heat in the kitchen is heard in the bedrooms.
Hushing, testing and replacing
If you can see and name the heat source, press the test/hush button. Aico documents a 10-minute silence on the 3000 Series, which also silences interconnected alarms. If the cause is still there when the 10 minutes ends, the alarm sounds again.
If you cannot name the cause, do not hush it and go back to bed.
Test monthly by holding the test button for about 10 seconds and confirming a loud, clear tone. Test the backup supply yearly on mains units by switching the circuit off at the board and checking that the power LED flashes. Never test with a flame.
Replace the alarm when the label says so, when a sealed battery reaches the end of its life, when it reports a sensor fault, or when it keeps chirping after the supply has been restored.
If you rent
A heat alarm in a rented kitchen is part of the landlord’s fire detection system, usually wired in with the rest of it. Report the fault with the model number and the pattern, and ask for a like-for-like replacement.
Push back on any suggestion that a hallway or bedroom smoke alarm could be swapped for a heat alarm because it keeps going off. That is not a fix, and it would leave the escape route with detection that cannot do the job.