Find out how well ventilated your home is
CO2 monitors display and record carbon dioxide levels (CO2), temperature and relative humidity (% RH). We breath out CO2 and humidity all of the time, and lots household activities produce moisture too, like showering, cooking and drying clothes. But too much or too little CO2 or humidity usually indicate poor ventilation, which may cause a range of problems problems. For example:
Unfortunately, most people aren’t good at noticing when the air is stuffy, so CO2 monitors are a useful tool which allow us to see how well ventilated our homes and take action if needed.
It’s possible to reduce draughts and control ventilation with window trickle vents, by opening windows and running extractor fans, as needed. If you have one, you can also use a ventilation system like an MVHR.
We recommend using one to check the ventilation during normal use, in rooms where you spend most time – probably living rooms and overnight in bedrooms. Maybe check how long it takes for the bathroom to return to good humidity (ideally 60% RH or less) after a shower.
The logging function is good for overnight tests, recording hourly measurements. Then connect the monitor to a computer via USB; it appears as a disk drive, containing a CSV file of recent readings.
If indoor CO2 remains less than 800ppm and it’s cold outside, you may be wasting heat from draughts or too much ventilation.
* This rising CO2 level is the main cause of climate change!
5,000 ppm** CO2 as the long-term (8-hr) workplace exposure limit.
HSE Guidance advises actions for these CO2 levels:
1500ppm Take action to improve ventilation where CO2 readings are consistently higher than 1500ppm
800ppm or less is likely to indicate that a space is well ventilated.
Where there is continuous talking or singing, or high levels of physical activity, provide ventilation sufficient to keep CO2 levels below 800ppm
**ppm = parts per million
Raised CO2 levels can also indicate a higher risk of COVID-19 transmission as a result of poor ventilation. More people in a smaller space that has poor ventilation, especially if they’re active and breathing hard, all increase the risk.
UK Government has sent 300,000 CO2 Monitors to all schools to monitor for this risk.
Don’t confuse this Carbon Dioxide (CO2) Monitor with Carbon Monoxide (CO) Alarms. Carbon Monoxide is the seriously poisonous gas made by incomplete combustion. It’s good to have one to warn you of dangerous CO levels, if you have a home appliance or fire burning gas, wood, etc, especially without a flue.