Where Should Smoke and Carbon Monoxide Alarms Go in an Irish Home?

Shopping for smoke, heat and carbon monoxide alarms? See the range, with free delivery anywhere in Ireland from the first euro.

Smoke alarms belong on the ceiling in the hallway and on every landing, one on each floor, positioned so you would hear them from a bedroom with the door shut. Carbon monoxide alarms belong in whatever room has a fuel burning appliance, on the ceiling or high on a wall, one to three metres from the appliance. Kitchens and garages need a heat alarm instead of a smoke alarm, because cooking and exhaust fumes will set a smoke alarm off constantly.

Those three sentences cover most Irish homes. At Shamrock Electrical in Rathcoole, just off the N7, we stock mains powered alarms with battery backup, and this is the practical guidance we give across the counter.

Smoke alarms: where and why

The purpose is to wake you, so placement is about the route smoke travels and whether you would hear it asleep.

• One on every floor, at minimum. A single alarm downstairs will not reliably wake somebody upstairs with a bedroom door closed.
• Hallways and landings, because that is the escape route and where smoke collects as it rises.
• On the ceiling, centrally where possible, because smoke rises and spreads along the ceiling first.
• Not in the corner. Keep at least 300mm from walls and light fittings. Air moves poorly in corners and smoke can take noticeably longer to reach the sensor.
• Not right beside a bathroom door, where steam causes false alarms and people end up taking the battery out, which is far more dangerous than the nuisance.

Our Evolec mains smoke detector is interconnectable, which is the feature worth paying for. Interconnected means when one alarm detects, they all sound. A fire starting in the kitchen at night is heard upstairs immediately rather than once it has spread far enough to reach a second sensor.

Carbon monoxide alarms: a different job entirely

This is the one people get wrong most often, because the rules for where it goes are different from a smoke alarm.

Technical Guidance Document J (Heat Producing Appliances, 2014) sets out where it goes in the room with the appliance: on the ceiling at least 300mm from any wall, or on a wall as high as possible, above any doors and windows but not within 150mm of the ceiling, and between 1000mm and 3000mm horizontally from the appliance, or in accordance with the manufacturer's instructions. Alarms in bedrooms should be relatively close to the breathing zone of the people sleeping there. Follow the instructions supplied with the specific alarm, because manufacturers differ slightly.

Put one in any room with a fuel burning appliance. That means gas boilers, oil boilers, solid fuel stoves, open fires, gas fires and range cookers. Also worth having in a bedroom above or beside a boiler.

Keep it a sensible distance from the appliance itself, typically one to three metres, so normal start up does not trigger it. Not directly above a stove or fire.

Avoid damp spots, direct sunlight, right beside a window or extractor, and enclosed cupboards.

Our Evolec carbon monoxide alarm is mains powered with 9V battery backup, so it keeps working through a power cut, which is exactly when people light fires and run generators.

Kitchens, garages and lofts need a heat alarm

A smoke alarm in a kitchen is a false alarm generator. Toast, frying and steam will set it off, and the alarm that cries wolf is the alarm somebody disconnects.

A heat alarm triggers on a rapid temperature rise instead, so normal cooking does not bother it. The Evolec heat alarm is mains powered with battery backup and interconnectable, suited to kitchens, garages, lofts and anywhere else a smoke alarm is unsuitable.

Interconnect it with the smoke alarms. A heat alarm on its own in a kitchen is far less useful than one that sets off every alarm in the house.

Mains or battery?

Mains powered with battery backup is the better arrangement, and in Ireland it is generally what is required in new build and rental properties. Confirm the current requirement for your situation, because rules differ between owner occupied, rented and new build.

The reason is simple. A battery only alarm depends on somebody replacing a battery. A mains alarm with backup works regardless, and the backup covers power cuts. All three of our Evolec alarms are mains with 9V backup, and all are interconnectable.

A short checklist

• Smoke alarm on every floor, hallway and landing, on the ceiling, 300mm clear of walls
• Heat alarm in the kitchen and garage, not a smoke alarm
• CO alarm in every room with a fuel burning appliance, on the ceiling or high on a wall, one to three metres from the appliance
• Interconnect them all so one triggers the rest
• Mains powered with battery backup, fitted by a registered electrician
• Test monthly, and replace CO alarms at the end of their stated life, typically seven to ten years

Buying alarms from Shamrock Electrical

We are an Irish owned electrical supplier in Rathcoole, County Dublin, just off the N7 and well positioned for the M50. We stock mains powered smoke detectors, heat alarms and carbon monoxide alarms, all with 9V battery backup and all interconnectable, and we deliver free on every order to all 26 counties with no minimum spend. You are also welcome to collect from the counter.

The range is in smoke and carbon monoxide alarms.

Frequently Asked Questions

Q: Where should a carbon monoxide alarm be placed in a house?
A: In any room containing a fuel burning appliance such as a boiler, stove, open fire or range cooker, on the ceiling or high on a wall, and typically one to three metres from the appliance so normal start up does not trigger it. Avoid damp areas, direct sunlight and enclosed cupboards, and follow the instructions supplied with the alarm.

Q: Should a carbon monoxide alarm go on the ceiling?
A: It can. In the room with the appliance, Technical Guidance Document J allows the ceiling, at least 300mm from any wall, or a wall position as high as possible, above doors and windows but not within 150mm of the ceiling, between 1000mm and 3000mm from the appliance. Alarms in bedrooms should be relatively close to the breathing zone of the people sleeping there.

Q: How many smoke alarms do I need in a house?
A: At least one on every floor, sited in the hallway and on each landing so they can be heard from bedrooms with the doors shut. Larger homes need more. Interconnected alarms are strongly preferable, because one detecting sounds them all.

Q: Can I put a smoke alarm in a kitchen?
A: It is not advisable. Cooking and steam cause frequent false alarms, and an alarm that goes off constantly tends to get disconnected. Use a heat alarm in a kitchen or garage instead, which triggers on a rapid temperature rise rather than smoke, and interconnect it with the smoke alarms.

Q: Do smoke alarms need to be mains powered in Ireland?
A: Mains powered with battery backup is the better arrangement and is generally what is required in new build and rental properties. Requirements differ between owner occupied, rented and new build, so confirm what applies to your situation. Mains alarms should be fitted by a registered electrician.

Q: What does interconnected mean and is it worth it?
A: Interconnected means that when one alarm detects, every alarm in the house sounds. It is worth it. A fire starting downstairs at night is heard upstairs immediately, rather than only once smoke has spread far enough to reach a second alarm.

Q: Where can I buy mains powered smoke and carbon monoxide alarms in Ireland?
A: Shamrock Electrical stocks Evolec mains smoke detectors, heat alarms and carbon monoxide alarms, all with 9V battery backup and all interconnectable. We are in Rathcoole, County Dublin, just off the N7, and we deliver free to every county in Ireland on every order with no minimum spend. You can also collect from the counter.