How to install and test a carbon monoxide detector

Please note, we can only give you basic advice on this page to do the job yourself. Make sure you use the right tools and protective equipment to avoid hurting yourself or damaging your home. Always consult a professional for more complex repairs.

Carbon monoxide is formed when fuels such as gas, oil, coal and wood don't fully burn. These sources of fuel are used in many household appliances, such as:

• Boilers

• Gas fires

• Central heating systems

• Cookers

• Open fires

• Water heaters

Incorrectly installed, badly maintained or poorly ventilated appliances such as heaters, cookers and boilers are the most common causes of accidental exposure to carbon monoxide.

Therefore, it's important to have carbon monoxide detectors installed; Which? recommend that for every fuel-burning appliance you have, you have a carbon monoxide detector.

If you only have a gas boiler, you'll only need one carbon monoxide detector. However, if you have other appliances such as a gas fire, a fuel burning range cooker or a log-burner, you'll need to fit a detector in each room these appear.

How to install your carbon monoxide detector

Setting up and installing a carbon monoxide alarm is a simple task that you can do yourself and can be as straightforward as resting it on a high shelf in a room with a fuel-burning appliance.

Always read the manufacturer's instructions on how to site, test, service and replace the alarm; pay particular attention to the unit's battery life and when it'll need replacing. The majority of alarms will last between five and seven years, and some even up to ten. You can also find alarms that plug directly into an outlet or those that are wired into a wall by an electrician.

Where to install your carbon monoxide detector

Fit your alarm high-up and in the same room as the potential source of carbon monoxide, approximately 15cm from the ceiling and at least a metre away from boilers, cookers and fires. It doesn't need to be fixed to a wall; a shelf is often suitable.

Tip: you should be careful not to install a detector behind furniture, enclosed spaces (such as a cupboard) or behind curtains. It's best not to place them next to windows, vents, or in damp areas like bathrooms. This will prevent the device from effectively detecting carbon monoxide.

How to test a carbon monoxide detector

Make sure you test your alarm regularly using the test button. Get into the habit of replacing the batteries annually or as soon as you hear the low battery signal. Sealed battery alarms will have a battery that'll last as long as the alarm and won't need to be replaced.

You can also test the sensor of your unit occasionally by using a canned CO detector test spray. This is a non-flammable aerosol; simply press the spray nozzle for at least 3 seconds. Your alarm should sound within minutes.

Smart carbon monoxide detectors

If you're interested in making your home smarter, as well as safer, you could consider a 'smart' carbon monoxide detector. These have high-tech features such as smartphone notifications and monitoring through a mobile app which ensure your home remains safe while you're away.

These alarms also use control panels (or mobile apps) to manage voice location settings. The alarm's voice will clearly state the room where carbon monoxide is detected and can connect to other home smart devices seamlessly for a safe home you can control from wherever you are.

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