CO alarm checklist
The calculator needs JavaScript. The worked example, formula and figures below show exactly how it works, so you can do the sum yourself. A guide, not advice. Check the figures against your stove's manual, your supplier and your installer.
Short answer
Answer a few quick questions about the carbon monoxide alarm near your stove: is it in the same room, positioned as its maker says, checked with its test button, and inside its replace-by age? The checklist shows what's covered and what still needs doing. It takes about two minutes.
Worked example
| You enter | Value |
|---|---|
| There's a carbon monoxide alarm in the room with the stove | Yes |
| It's positioned where the alarm maker's instructions say | Yes |
| You've pressed the test button recently, as the manual says | No |
| Age of the alarm | 4 years |
| Replace-by age on the alarm's label or manual | 7 years |
3 of 4 checks done: 1 thing to do
| Result | Value |
|---|---|
| Checks done | 3 of 4 |
| Years until it needs replacing | 3 years |
What to do
- Press the test button now, and set a reminder to test it as often as the manual says.
Show the working
- Years left: 7 − 4 = 3
- 3 of 4 checks done
How it works
- One check each: an alarm in the stove room, positioned as the maker says, test button pressed recently, and within its replace-by age
- Years left = the replace-by age on the label − the alarm's age
A CO alarm is a back-up, not a substitute for a swept chimney, a properly installed stove and dry fuel. The rules on fitting an alarm with a new stove differ between England, Wales, Scotland and Northern Ireland: your installer will know which apply.
Assumptions and sources
The figures this calculator starts from, and where each comes from. Your stove's spec plate, your supplier and your own meter readings come first: change any figure to match.
This calculator has no built-in defaults: every figure comes from you or your product's data.
What to buy
Look for an alarm marked to BS EN 50291 with a sealed battery that lasts the life of the alarm (check the label).
FAQs
Do I need a CO alarm with a wood burner?
The legal rules depend on where you live and when the stove was fitted. See do I need a CO alarm with a wood burner? Whatever the rules say, fit one.
Where should the alarm go?
In the same room as the stove, positioned as the alarm maker's instructions say.
How often should I check it?
As often as its manual says, using the test button.
When should I replace it?
At the replace-by age printed on its label or in its manual.
Guides
Best carbon monoxide alarms (UK): specs compared
CO alarms compared on makers' specs: standard, battery life and display. Not tested. Where to fit one with a stove.
Carbon monoxide and wood burners: stay alert
Why stoves can produce carbon monoxide, the warning signs, and the alarm, sweeping and ventilation that guard against it.
Do I need a CO alarm with a wood burner?
When the rules require a carbon monoxide alarm with a stove in England, Wales, Scotland and NI, and where to put it.