On 7 Jan 2021 18:23:48 GMT, David wrote:

We have a mains powered CO tester in the same room as our log burner.

However I am wondering if there is a sensitive portable CO tester which
is good.

https://www.amazon.co.uk/Handheld-Mo...ector-0%EF%BD%
9E1000ppm/dp/B08CSLLXVC/
is an example after a quick search.

"2. Safety Information"
"Do not use the meter as a personal safety monitor."

The main question is if these detectors are more accurate/sensitive than
the ones designed for permanent installation.

CO is rather insidious toxin. It's not a simple above a certain level
you'll likely die. True enough the higher the concentration the
quicker you die but long exposures to low levels can also kill and/or
be bad for your general health. The CO binds very tightly to your
haemoglobin and stops it being able to carry oxygen around your body.
The tight bonding means that even low levels can build up high levels
of carboxyhaemoglobin.

https://www.nhs.uk/conditions/carbon...ide-poisoning/

A decent CO alarm has several alert states which sort of range from
"Hey, there is more than background CO about" to "Get the F out
NOW!".

--
Cheers
Dave.