Best Carbon Monoxide Detectors in 2026, Tested and Reviewed

Rating

10 / 10

★★★★★

Dewlora 4 in 1 Detector

The Dewlora 4-in-1 is the only detector we tested that shows you real-time numbers AND detects all three deadly gases: carbon monoxide, natural gas, and propane.

Unlike every other detector on this list, you're not trusting a green light that just means "power on." You see actual PPM readings. Zero means safe. If that number climbs, you know immediately — before you feel sick, before it's an emergency.

The game-changer is the multi-gas detection. Standard CO detectors are completely blind to natural gas and propane leaks. Your stove could be leaking. Your furnace could be leaking. Your water heater could be leaking. And your CO detector? Silent. Green light glowing.

Dewlora sees everything. That's why firefighters recommend it.

Rating

7.5 / 10

★★★★☆

Nest Protect

If you want smart home integration and voice alerts, Nest Protect is the premium choice for CO and smoke detection.

But here's the problem: it still can't see natural gas or propane. And it doesn't show you real-time numbers. You get alerts when levels are already dangerous — not before.

For $129, you're getting a smarter version of the same limited protection. It's a better experience, but not better coverage. If your gas stove leaks, Nest Protect stays silent.

It's a good CO detector. But it's still just a CO detector.

Rating

4.5 / 10

★★☆☆☆

Steadfast Haven CO Detector

Steadfast Haven markets itself as a premium home safety brand — but after testing, we found the product falls significantly short of its bold claims.

Yes, it detects CO, natural gas, and propane. But detection alone isn't enough. The alarm threshold is dangerously slow to trigger — alerting well after levels had already climbed into the danger zone. That delay could cost you precious minutes in a real emergency.

The display is minimal and hard to read in low light. You get no real-time PPM readout — just a basic indicator that tells you very little about what's actually in your air.

Customer reviews on third-party sites tell the same story: buyers feel misled by the marketing. Several reported the unit stopped working within months. The return process was described as frustrating and slow.

Bottom line: Steadfast Haven charges premium prices for protection that isn't premium. It detects the right gases — but reacts too slowly and shows you too little. You're paying for branding, not performance.

Rating

6 / 10

★★★☆☆

Kidde Nighthawk

Kidde Nighthawk is one of the few budget detectors with a digital display — which is a step up from a green light.

But it only shows CO levels. Natural gas? Can't see it. Propane? Blind to it.

You're getting half the picture. Literally. Your house could be filling with explosive gas and Kidde shows you "0" because it's only looking at carbon monoxide.

The display is nice. But it's like having a speedometer that only works sometimes. Partial information can be worse than no information — it makes you think you're safe when you're not.

Rating

5.5 / 10

★★★☆☆

First Alert SCO5CN

The SCO5CN combines smoke and CO detection, which sounds efficient. One device. Two hazards. Done.

But it's still blind to the third hazard that kills families: gas leaks.

And like every other green-light detector, you have no idea what's actually happening in your air. Is your CO level at 5 PPM? 40 PPM? 69 PPM? You don't know. The green light glows the same.

Combo detectors feel smart. But you're combining two limited sensors into one limited device. That's not protection. That's convenience disguised as safety.