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How to fit smoke alarms

Updated: 20 October 2026

How to fit smoke alarms, once the pack is already in the hall, comes down to three checks: the right head on the right ceiling, screws rather than a pad, and a test in which every alarm sounds. A textured ceiling, a smoke alarm over the hob, and a beep from only the head under your finger are the failures this page is for. It uses GOV.UK, London Fire Brigade and published fitting notes. It is not a ranking of the twelve packs in the [smoke alarm set comparison](/hub/fire-protection/smoke-alarm-set). A qualifying purchase can earn a commission at no extra cost to you.

How to fit smoke alarms, once the pack is already in the hall, comes down to three checks: the right head on the right ceiling, screws rather than a pad, and a test in which every alarm sounds.

Our top picks

WISUALARM WISUALARM DHI-HY-SA20A 2-pack

Best overall

WISUALARM WISUALARM DHI-HY-SA20A 2-pack
6.8/10about £18.69
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XINDUM XINDUM SM11R4 bundle

Rank 2

XINDUM XINDUM SM11R4 bundle
8.8/10about £96.99
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XINDUM XINDUM 2-smoke bundle

Best value

XINDUM XINDUM 2-smoke bundle
8.7/10about £69.48
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On this page
  1. 1.Where each head in the set goes
  2. 2.Screw the base, and treat pads as a last resort
  3. 3.Prove the link before you trust the ceiling
  4. 4.The monthly test, and when you stop

Where each head in the set goes

Fit a smoke alarm on the ceiling, as near the centre as you can, at least 300 mm from walls, corners and light fittings. Do not put a smoke alarm in a kitchen or a bathroom. The kitchen head, if your pack has one, is the heat alarm. If the box is smoke only, do not make do with an optical head over the hob. Whether a heat head belonged in the set is in the smoke alarm set buying guide. Wall mounting is a fallback only when the maker allows it, 150–300 mm below the ceiling. A landing is its own ceiling.

Screw the base, and treat pads as a last resort

Before you drill, check that you are not about to hit a cable. Screw the base to the ceiling, then twist the head onto the base the way the manual shows. London Fire Brigade’s warning on glue is the one to keep: adhesive can seep into the alarm and stop it working. Several packs in this comparison include sticky pads, including LINKD, WISUALARM and HEIMAN, and pads are a known failure on a textured ceiling such as Artex. Use the screws even when the pads look firm on day one. If the circuit is 230 V, or you are joining an existing hard-wired system, stop and use an electrician. A battery set does not change that rule.
WISUALARM WISUALARM DHI-HY-SA20A 2-pack

Testsieger

WISUALARM WISUALARM DHI-HY-SA20A 2-pack
6.8/10about £18.69
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The monthly test, and when you stop

GOV.UK and the Fire Kills campaign say you should test at least monthly. Hold the button until the alarm sounds. Some fire services, including Surrey, say weekly. Treat that as their habit, not as a correction of the monthly line. Do not test with a flame, a vape or a cigarette. A sealed unit that has failed is replaced, not re-celled. Stop if you cannot reach the ceiling safely, if the property is an HMO, or if the work is 230 V. If an alarm sounds and you cannot find a reason, get everyone out and call 999. The Scottish room count is on the Scotland page.

Common questions

Can I use the adhesive pads in the box?
You can, and you should not rely on them. London Fire Brigade warns that glue can seep into the alarm and stop it. Pads also fail on textured ceilings such as Artex. Several captured packs include pads, and the better fix is screws through the base after you have checked for cables. If a pad is all you have and the ceiling is stippled or newly painted, get screws before you call the fit finished.
Do I pair the alarms before or after I drill?
Pair them before you drill, on a table where you can hear every head. Prove the link, then mark the ceiling and screw the bases. Finding out that two heads never paired, after the holes are made, means a second trip up the ladder. Standalone alarms that were never sold as interlinked do not need a pairing step. They still each need their own test before you trust them.
How do I know the set is actually interlinked?
Press the test control and wait until every head in the set sounds, not only the one you are touching. A local beep proves that one alarm has power. It does not prove the radio link. Follow the hold time in your own manual. Aico and Hispec publish different times for their own alarms, so a single number copied from another brand is the wrong instruction for the pack in your hand.
How often do I test, and what if I cannot reach?
Test at least monthly, which is the GOV.UK and Fire Kills line. Hold the button until the alarm sounds. Some fire services prefer a weekly press. If you cannot reach safely, ask your local fire and rescue service about a fitting visit rather than standing on an unsteady chair. A remote helps only if it actually triggers every head when you try it from the floor.
What if the alarm chirps, or sounds for no reason I can find?
A chirp is usually a fault or a cell warning. Read the manual, and do not pull a battery just to get silence if the alarm may be warning you. A sealed unit that has failed is replaced, not re-celled. If the alarm sounds and you cannot explain it, get everyone out and call 999. Do not stay inside searching for burnt toast while the rest of the household waits to see.

Related pages

Best smoke alarm set

Smoke alarm set

Smoke alarm set: how to choose the pack for UK rooms

Landlord smoke alarm requirements in England, Wales and NI

Interlinked smoke alarm kit Scotland: the room count

Sources

Public UK sources for this comparison, last checked on 19 October 2026. Listing prices and ratings are the amazon.co.uk pages captured the same day.

  1. The Smoke and Carbon Monoxide Alarm (England) Regulations 2015, regulation 4 (retrieved 19 October 2026)
  2. GOV.UK smoke and carbon monoxide alarm Q&A for landlords (retrieved 19 October 2026)
  3. Scottish Government: fire and smoke alarms in Scottish homes (retrieved 19 October 2026)
  4. Scottish Government: where and what to buy (retrieved 19 October 2026)
  5. Tolerable standard guidance: fire and carbon monoxide detection (retrieved 19 October 2026)
  6. Renting Homes (Fitness for Human Habitation) (Wales) Regulations 2022, regulation 5 (retrieved 19 October 2026)
  7. Northern Ireland: smoke, heat and carbon monoxide alarms in private tenancies (retrieved 19 October 2026)
  8. GOV.UK: fire safety in the home (retrieved 19 October 2026)