How to Fit a Carbon Monoxide Detector

When it comes to the safety of your home, a carbon monoxide detector is essential. Carbon monoxide (CO) is a colourless, odourless and tasteless gas. Excess CO is produced if carbon-based fuel does not burn properly or in cases where gas boiler flues are incorrectly installed.

CO is known as the ‘silent killer’ as humans can’t naturally detect it and there are around 50 deaths a year in the UK due to carbon monoxide poisoning. What’s more, in extreme cases where low levels are inhaled over a prolonged period it can cause paralysis and brain damage as it starves cells, tissue, the brain and organs of vital oxygen.

Symptoms of Carbon Monoxide Poisoning

Low level exposure to carbon monoxide can cause symptoms similar to flu or food-poisoning, such as:

  • Tension-type headache
  • Dizziness
  • Nausea and vomiting
  • Tiredness and confusion
  • Stomach pains
  • Breathlessness

However, carbon monoxide poisoning won’t cause a high temperature. Symptoms may subside a little when away from the CO source.

Higher levels or prolonged exposure to carbon monoxide can cause:

  • Loss of consciousness
  • Collapse
  • Chest pains
  • Erratic behaviour
  • Visual impairment
  • Vertigo
  • Ataxia
  • Raised heart rate
  • Seizures

Avoiding Carbon Monoxide Poisoning

As ever, we believe that prevention is key and although sometimes carbon monoxide leaks can’t be helped, there are ways in which you can try to prevent them from happening:

  • Ensure you use a Gas Safe Registered engineer when having any gas appliance installed in your property
  • Get your appliances serviced regularly, even if you have CO alarms in your property
  • Have your chimneys and flues swept at least twice a year by a qualified sweep
  • When installing wood or coal burners, get it fitted by a HETAS approved installer
  • When BBQing, ensure that the barbeque is completely cooled before bringing it back inside the garage, or even a tent if you’re camping
  • Check car exhausts every year for leaks
  • Check that your car exhaust isn’t blocked before turning your engine on
  • Ensure that rooms are well-ventilated and air vents are unblocked
  • Fit an extractor fan in your kitchen

Where to Install a Carbon Monoxide Detector

Generally, the more fuel-burning appliances you have in your home, the more CO alarms you will require. Whether you have a log burner or gas fire in your living room or a gas boiler in your kitchen, you will need a carbon monoxide detector in each of these rooms.

CO detectors should be installed high up in any room with a fuel-burning appliance. They should be placed around 15cm from the ceiling and least 1m from any boiler, fire or cooking appliance but not directly above any appliances that gives off heat or steam.

Many carbon monoxide alarms don’t need to be fixed to a wall and can be set on a shelf while still meeting the criteria for being high up, avoiding heat or steam and being 1m away from the appliances mentioned.

Fitting a Carbon Monoxide Detector to the Wall

Before you begin to fit your carbon monoxide detector to the wall, ensure that you are installing your carbon monoxide alarm as per the manufacturer’s guidelines.

Some detectors will be unsuitable for wall-mounting, or won’t require it, so be sure to read the manufacturer’s instructions before following this guide.

What you will need

  • Measuring tape
  • Pencil
  • Drill
  • Hollow wall plugs/plasterboard anchors
  • Carbon monoxide detector and fixings (screws and sometimes wall plugs)


  1. Using your measuring tape, find a spot for your alarm – around 15cm from ceiling and at least 1m from boiler, gas fire or fuel burning appliance.
  2. Using your pencil, mark fixing points for drilling using the base plate of CO alarm.
  3. Drill holes using your fixing point markings. If you are drilling into a plasterboard wall, drill into the plasterboard and put wall plugs/anchors in the holes to reinforce them before doing anything else.
  4. Screw the baseplate of the carbon monoxide detector to the ceiling. However, be careful not to do this too tightly as you risk damaging the wall plugs you may be using to reinforce your placement holes.
  5. Fit the alarm battery and then fit the main body of your CO detector to the baseplate, following the manufacturers guidelines.
  6. Test your new alarm.

Maintaining and Testing

Keeping your CO alarm in perfect working condition and testing it regularly could end up saving lives. We recommend:

  • Picking a day of the week – we suggest Monday as it’s the first day of the week – to test your carbon monoxide detector AND your smoke alarm. Keep a note of it on a board somewhere so you don’t forget.
  • Changing the battery once a year, even if the alarm is still working, unless you have purchased a sealed battery alarm which will last the lifetime of the alarm
  • Replacing your alarm every five years or according to the manufacturer’s guidelines
  • Cleaning your carbon monoxide detector a few times a year
    • Use the soft brush attachment on your vacuum to gently vacuum the alarm, removing any dust from the sensors

We hope that you’ve found this guide useful and that you’ll follow the steps outlined in this guide to keep your home and family safe.