Gas Leak Detectors

Who this is for

This collection covers two genuinely different purchase decisions that both fall under "gas leak detection." Read the split below before picking a product -- they are not interchangeable.

Installed, fixed alarms (leave running continuously)

First Alert GCO1CN and Kidde KN-COEG-3 are both AC plug-in alarms you install in your home and leave running. Each detects combustible gas (natural gas/methane and propane) and carbon monoxide in one unit, with a digital display and 9V battery backup. They are the right choice if what you want is ongoing, unattended protection in a fixed location -- the kind of device you install once and forget about (aside from periodic testing).

The two are close alternatives from different brands rather than meaningfully different products: both are plug-in combo CO+gas alarms with a digital display, and both document the same mounting guidance (mount high for natural gas, which rises; mount low for propane, which sinks). Kidde's own documentation names a UL mark on its user guide's cover without spelling out the specific standard number in the guide's text; First Alert's spec sheet names "UL1484 and 2034" explicitly. That is a real, if minor, difference in how specific each manufacturer's own documentation is -- not a claim that one device is more or less genuinely certified.

Read the full First Alert GCO1CN review for the sourced certification and specification detail behind that comparison.

Portable, handheld leak locator (a different tool for a different job)

UEi CD100A is not a fixed alarm at all -- it's a handheld sniffer with an 18-inch flexible gooseneck probe, meant to be carried around and used to pinpoint exactly where a suspected leak is coming from (for example, checking fittings and connections near a stove or water heater). It does not detect carbon monoxide, has no digital display or continuous monitoring, and is powered by a 9V battery rated for about 5 hours of use. Its manufacturer describes it as a serviceman's tool for residential and small-commercial use, though it is worth knowing Amazon itself lists this product under an "Automotive Fuel Leak Detectors" category, not a home-safety one -- a sign this tool sees professional and automotive use as much as household use.

Buy this if you specifically want to locate a leak you already suspect, not as a substitute for one of the fixed alarms above.

Limitations

• No product in this collection is a natural-gas-only fixed alarm (no CO detection). Both fixed options detect CO as well as combustible gas; if that is not what you want, this collection does not currently have an alternative.
• Certification claims above are manufacturer statements from each product's own documentation, not independently confirmed by Silent Home Hazards against UL's own records.