CO2 Alarms

What is carbon dioxide?
Carbon dioxide (called CO₂ for short) is a gas we naturally breathe out. You can’t see it or smell it, but when too much CO₂ builds up inside a home, it can mean the air is stale and needs fresh air from outside.

What does a CO₂ monitor do?
A CO₂ monitor is a small device that:
• Measures how much CO₂ is in the air
• Displays either a number or a coloured light (green, amber or red), indicating when ventilation is needed
• It is not an alarm like a smoke or carbon monoxide alarm
• Let’s tenant’s know when fresh air is needed.

Why is this important in new homes?
New homes in Scotland are built to be:
• Well insulated
• Energy efficient
• Airtight to prevent heat loss

This is good for energy costs, but it also means:
• Old air can get trapped inside
• Moisture and smells build up more easily
• Rooms can feel stuffy, causing tiredness or headaches

A CO₂ monitor helps households know when fresh air is needed, even if they can’t feel the problem yet.

When did this become a requirement?
The requirement comes from the Scottish Building Regulations. In October 2015, the Scottish Government updated its guidance around airtight homes, to ensure they have CO monitors as part of ventilation requirements.
If your home was built before October 2015 it’s unlikely to have a CO₂ monitor installed in your property. There are currently no plans to install CO₂ monitors in our older homes.

One important thing to remember
A carbon dioxide (CO₂) monitor is different from a Carbon monoxide (CO) alarm.
Carbon monoxide alarms warn people about a dangerous gas, and are installed in homes with gas appliances.
CO₂ monitors are about air quality and comfort, rather than warm of immediate danger.
You can read more about Scottish Governments building regulations relating to CO₂ monitors here:
https://www.gov.scot/publications/carbon-dioxide-monitors-standard-3-14-letter-to-local-authority-verifiers/