Not every CO2 monitor uses the same underlying sensor technology, and the difference genuinely affects reading accuracy.
What NDIR actually is
Non-dispersive infrared (NDIR) sensing measures CO2 by how much infrared light it absorbs at a specific wavelength — a direct, physical measurement method generally considered more accurate and stable over time than cheaper alternatives.
The cheaper alternative
Some budget monitors use electrochemical or estimated CO2 sensing instead, which can drift more over time and is generally considered less precise than NDIR, though it’s usually cheaper to manufacture.
Check the listing for the specific term
SwitchBot states NDIR explicitly for the Meter Pro CO2, alongside a ±50 ppm accuracy figure — a genuine technology disclosure most budget monitors in this family don’t make for their own CO2 sensor.
Not every monitor discloses this
Neither the TFA Dostmann AIRCO2NTROL Mini nor the Airthings View Plus states its CO2 sensor technology in the listings we checked — a real gap, and one worth factoring in if sensor precision specifically matters to your decision.
What we would not do
Assume any CO2 monitor uses NDIR unless the manufacturer states it explicitly. It’s genuinely worth paying attention to for anyone who wants a more reliable reading over time, but it isn’t universal across this category.
Check your own manual before you follow anything here. Humidity ranges, wattages, voltage and current ratings differ from model to model, and the manufacturer's figures take precedence over anything written on this site. We report what makers and monitors publish — a target humidity percentage, a heater's tip-over and overheat protection, a plug or thermostat's maximum load rating — and we never turn a reading into a health verdict or a diagnosis. Questions about air quality and health are matters for a qualified professional and your national health authority, and this site points you to them rather than restating them. Where wiring, voltage or load ratings are involved, matching them exactly to your appliance is a safety matter, not a technicality.
The questions that keep coming up
How do I know if a monitor uses NDIR?
Check the listing for the term explicitly — SwitchBot states an NDIR sensor for the Meter Pro CO2. Where a monitor doesn't name its sensor technology, as with the TFA Dostmann AIRCO2NTROL Mini and the Airthings View Plus in our own reviews, treat the CO2 sensor type as unconfirmed rather than assume NDIR.
Last reviewed 24 August 2026