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Best Free Carbon Monoxide Detector Apps

250+ iOS apps curated and reviewed

3.8 avg rating
19 free apps
Updated October 2026

Looking for free free carbon monoxide detector apps? 19 of our 250+ tracked titles are free to download — no subscription, no trial. The rest are premium picks worth paying for.

Compare top Free Carbon Monoxide Detector Apps (October 2026)

#AppPriceRatingAdsIn-App PurchasesUpdated
1OTG CO Leak DetectorOTG CO Leak DetectorFree—NoNoMay 2026
2CO2 sensorCO2 sensorFree3.4★ (7)NoNoOct 2026
3Tracer - Gas DetectorTracer - Gas DetectorFree3.7★ (3)NoNoOct 2026
4SPARROW - CO & Air QualitySPARROW - CO & Air QualityFree4.0★ (7)NoNoMay 2026
5Resideo ConnectResideo ConnectFree4.8★ (43K)NoNoOct 2026
6C02 MonitorC02 MonitorFree3.0★ (2)NoNoMay 2026
7Hansen Gas DetectorHansen Gas DetectorFree—NoNoMay 2026
8SAMON GLACIÄRSAMON GLACIÄRFree—NoNoJun 2026

Top Picks for Free Carbon Monoxide Detector

CO2 sensor#2

CO2 sensor by sighmon

Display SCD-41 CO2 readings.
Strong Contender
🔧 Utilities
3.4(7 ratings)
Free
CO2 sensor screenshot 1
CO2 sensor screenshot 2
CO2 sensor screenshot 3
CO2 sensor screenshot 4
CO2 sensor screenshot 5
CO2 sensor screenshot 6

Monitor CO2, temperature, and humidity levels in real-time using a Bluetooth sensor. Save readings with location data and sync them across Apple devices via iCloud. View historical data on a map.

Tracer - Gas Detector#3

Tracer - Gas Detector by ReFleX Wireless Inc.

for various gas leak detection
Worth Considering
🔧 Utilities
3.7(3 ratings)
Free
Tracer - Gas Detector screenshot 1
Tracer - Gas Detector screenshot 2
Tracer - Gas Detector screenshot 3
Tracer - Gas Detector screenshot 4

This app works with a smartphone-powered USB device to detect various gas leaks like methane and formaldehyde. It provides real-time monitoring and alerts to enhance safety at home or work. Pinpoint emission sources effortlessly for peace of mind.

More Free Carbon Monoxide Detector apps to explore