The MTI Industries Propane Leak Detector That Goes Off Before I Smell Anything

Last spring, I woke up at 2 a.m. to a faint hissing sound near my kitchen slide. My old propane detector — the one that came stock with my rig — didn’t make a peep. I grabbed a flashlight, found a loose fitting on the stove connection, and tightened it up. But I couldn’t stop thinking: how long had that been leaking? Hours? All night? That moment pushed me hard into researching every RV propane leak detector review I could find. I was not going to leave my safety up to a detector I couldn’t trust.

Propane is heavier than air. It sinks to the floor and collects quietly. By the time you smell that rotten-egg odor, the concentration may already be dangerous. That fact alone made me realize I needed something far more sensitive than what I had. I started asking around in forums, watching YouTube teardowns, and comparing specs late into several evenings.

The Dual-Sensor Detector That Won’t Let You Sleep Through a Slow Leak

Stock RV propane detectors are notoriously slow to trigger — sometimes they won’t alarm at all until you’ve got a hazardous concentration in your living space. The Safe T Alert Dual LP/CO picks up propane leaks faster and at lower concentrations than the OEM unit that came with your rig, which means you catch a loose fitting or a slow supply-line failure before it becomes a 2 a.m. nightmare.

What works

• Alarms at 1/4 LEL (lower explosive limit), catching small leaks that won’t register on cheaper detectors — you’ll hear it hiss before it becomes invisible danger.
• Dual sensor means it’s also monitoring CO from your furnace or water heater, so you’re not running a separate single-purpose unit.
• Flush mount sits flush against the ceiling or wall, doesn’t protrude like a plastic box and look like an afterthought.

What doesn’t

• Requires 12V DC hardwiring — no battery backup, so if your coach battery is dead, the detector is offline (install a dedicated fused line from your main panel).
• Higher sensitivity means occasional false alarms if you’re cooking heavily or if propane appliance ignition is slow — expect a few midnight screams while you adjust.

I second-guessed buying the 35-742-BL because the higher alarm threshold scared me — wouldn’t it go off too often? — but once I stopped burning stuff on the stove like I was running a diner, it proved itself by catching a weeping regulator fitting I would have missed for weeks. Get the Safe-T-Alert by MTI Industries 35-742-BR 35 Series Dual.

Fitting It

The Safe-T-Alert mounts to the wall or cabinet face with two screws; I used a stud finder to avoid hitting plumbing behind the galley wall. The wiring harness connects to a 12V circuit—I ran mine through a dedicated breaker rather than piggyback on an existing line, which took about an hour including fishing wire through the wall cavity. The sensor head itself is small enough that placement was flexible; I mounted it low on the kitchen wall since propane sinks. No calibration needed out of the box, though I did a test with a lighter held near the sensor to confirm it responded.

How It Has Held Up

Over eighteen months and roughly 12,000 miles, the detector has cycled through three seasons and two propane refills without false alarms. The first winter I watched for nuisance triggers from furnace startup—none came. After six months, I noticed the LED brightness hadn’t dimmed, and the audible test still produced a clean alarm tone. The real test came when I discovered a slow weep at a regulator connection in month fourteen; the detector caught it at a concentration I couldn’t smell yet, giving me time to shut down and repair without panic. Battery backup kicked in once during a shore power outage, confirming the backup cell was holding charge.

Where It Falls Short

• Requires 12V hardwired installation; no battery-only option means it’s useless if your rig’s electrical system fails completely, unlike a standalone propane sniffer you can carry.
• Dual CO/LP monitoring is useful but adds complexity—if the CO sensor fails, you lose both alarms, whereas separate detectors let you replace one without losing the other.
• At roughly $150–180, it costs three to four times what a basic OEM replacement runs, making it a tough sell for someone who only dry camps a few weekends per year.
• The wall-mounted design means it won’t catch leaks in the propane locker or exterior regulator area—you still need a handheld sniffer for those spots.

Would I Buy It Again

I’d buy it again without hesitation. For anyone who lives full-time in an RV or spends extended seasons on the road, the sensitivity and dual-sensor peace of mind justify the cost. Skip it if you’re a weekend warrior with a newer rig under warranty, or if you’re willing to carry a handheld detector and do manual checks. But if you’ve ever wondered how long a leak went unnoticed, this catches the answer before it becomes dangerous.