6 Best RV Propane Detectors For Under Sink Nomads Swear By
Ensure your RV’s safety with a reliable propane detector. We review 6 nomad-approved models for under-sink installation, providing vital early leak alerts.
You wake up to a faint, foul smell, like rotten eggs. Is it the holding tank, or something worse? That brief moment of panic is exactly why a reliable propane detector isn’t just a good idea—it’s one of the most critical pieces of safety equipment in your rig. This isn’t about fancy gadgets; it’s about a device that stands guard while you sleep, ready to scream at the first sign of invisible danger.
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Why Under-Sink LP Gas Detection Is Critical
Propane is heavier than air. This isn’t just a fun fact; it’s a life-or-death principle in a small space. When a leak occurs from a fitting, a hose, or an appliance, the gas doesn’t float up and away. It sinks, pooling on your floor like an invisible puddle.
The under-sink cabinet is often ground zero for potential leaks. It’s a major junction for your rig’s plumbing, with lines and fittings for the kitchen cooktop, and sometimes the furnace, running through this unseen space. A tiny, slow leak from a compression fitting here can fill the cabinet and then spill out into your main living area, starting from the floor up.
You can’t rely on your nose alone. The chemical odorant (ethyl mercaptan) added to propane can be missed if you have a cold, allergies, or are in a deep sleep. This phenomenon, called "odor fade," can also happen if the leak is very slow or interacts with rust or moisture. An electronic detector is your 24/7 safeguard, sniffing the air at the most critical location so you don’t have to.
MTI Safe-T-Alert 35 Series: The RV Standard
Upgrade your RV's safety with this dual propane and carbon monoxide alarm. Its patented design offers reliable 12V powered detection, easy flush-mount installation, and advanced features like alarm mute and self-resetting for continuous protection.
If you’ve ever looked inside a factory-built RV, you’ve likely seen an MTI Safe-T-Alert. This is the industry benchmark for a reason. It’s a no-frills, 12V hardwired unit designed specifically for the harsh vibrations and temperature swings of a mobile environment.
Its operation is dead simple: a green light means it’s working, and a piercingly loud alarm means you have a problem. There’s a single button to test the unit or temporarily mute it if it goes off from cleaning aerosols or other vapors. It does one job, and it does it reliably.
The most important feature many people miss is the end-of-life alarm. These sensors don’t last forever; they have a typical lifespan of about five years. The 35 Series will chirp to let you know when it’s time for a replacement. Think of it not as a permanent fixture, but as a crucial consumable, like the batteries in your smoke detector.
Dometic Atwood LP Detector: OEM Reliability
Safeguard your RV with this 2-in-1 detector, monitoring for dangerous carbon monoxide and propane leaks. Its 12V DC power and loud 85dB alarm provide essential protection for your motorhome or travel trailer.
Alongside MTI, the Dometic Atwood detector is the other major player you’ll find installed from the factory. If your rig is kitted out with Dometic appliances, there’s a good chance this is the detector watching over them. It’s built with the same focus on durability and simplicity.
Functionally, it’s nearly identical to the Safe-T-Alert. It runs on your 12V house battery system, features a simple test/mute button, and is designed to be flush-mounted into a cabinet face or wall. The choice between this and an MTI often comes down to what was originally installed in your rig.
When replacing an old unit, pay close attention to the cutout dimensions. While many are a standard size, some Dometic and MTI models have slightly different faceplates. Matching your replacement to the original brand can save you the headache of having to patch or re-cut your cabinetry for a clean fit.
KIDDE Nighthawk: Dual Propane & CO Safety
For those of us maximizing every square inch, a combination unit is a brilliant move. The KIDDE Nighthawk Propane and Carbon Monoxide detector combines two essential safety devices into one, saving space and simplifying installation. It’s a trusted name in home safety that has proven its worth in mobile spaces, too.
This model is typically a 120V plug-in unit, which is a key distinction. It’s an excellent choice for van conversions or skoolies where a 12V hardwired solution is more complex to install, provided you have a well-placed outlet near the floor. The battery backup is its killer feature, ensuring it keeps working even if your shore power disconnects or you shut down your inverter overnight.
Remember, while this unit detects both gases, placement is still dictated by the heavier one: propane. It must be plugged into an outlet no more than 12-18 inches from the floor to be effective. Placing a CO/LP combo detector on the ceiling, where you’d put a smoke detector, renders the propane sensor useless.
First Alert CO710: Plug-In Combo Simplicity
Protect your family with the First Alert CO710 carbon monoxide detector, featuring a 10-year battery for continuous monitoring and a digital display showing temperature and CO levels. The loud 85-decibel alarm alerts you to dangerous CO concentrations.
First Alert is another household name that offers a fantastic plug-in combo unit perfect for RV life. The CO710 model provides both propane and carbon monoxide detection with an added layer of information that gives serious peace of mind.
Its standout feature is the digital display. Instead of just waiting for an alarm, you can see real-time and peak levels of carbon monoxide (CO) in Parts Per Million (PPM). This can alert you to a small, intermittent issue with an appliance long before it becomes a life-threatening emergency.
Like the KIDDE, this is a 120V plug-in unit with battery backup, making it easy to install if you have an outlet in the right spot. The downside is its bulk; it’s larger than a flush-mount RV detector and will stick out from the wall. But for the added information and dead-simple setup, many nomads find that a worthy tradeoff.
EG Air Propane Detector: Modern Digital Display
Quickly pinpoint gas leaks with this portable detector. Its flexible sensor reaches tight spaces, while visual and audible alarms indicate gas concentration.
If you want more data than just a "go/no-go" alarm, the EG Air detector is a compelling modern option. It brings a level of precision usually found in industrial equipment into the RV, which is fantastic for anyone who likes to monitor their systems closely.
The key feature here is the bright LED screen that displays the gas concentration as a percentage of the LEL, or "Lower Explosive Limit." The alarm might be set to go off at 10% LEL, but the display will show you if levels are creeping up to 1% or 2%, giving you a much earlier warning to start ventilating and investigating.
Most of these units are 120V plug-in models and often feature a voice alarm that says "Warning: gas leak detected" before the siren, which can be slightly less jarring in the middle of the night. It’s a great choice for the tech-focused RVer who values information and early warnings.
RecPro RV LP Gas Detector: Easy-Install Upgrade
Detect propane leaks quickly and accurately in your RV with this 12V DC alarm. It features a digital display, loud 85dB alarm, and easy installation with included lever-nut connector.
RecPro has become a go-to name for aftermarket RV parts, and their LP detector is a perfect example of why. It’s designed specifically as a drop-in replacement for the most common MTI and Atwood models that come standard in many RVs.
The biggest selling point is the form factor. RecPro designed their detectors to match the cutout sizes and screw patterns of the major OEM brands. This means you can often unscrew your expired 5-year-old detector and install the new RecPro unit in minutes, with no cutting or drilling required.
This is a 12V hardwired unit, just like the factory models it replaces. It offers solid, reliable performance without extra bells and whistles. If your stock detector has expired and you want a fast, easy, and cost-effective replacement you can trust, this is almost certainly your best bet.
Choosing Your Detector: Wiring and Placement
Making the right choice comes down to two key factors: your power system and your installation constraints. There is no single "best" detector, only the best one for your specific rig and needs.
First, consider the wiring. 12V hardwired is the gold standard for RVs. These units connect directly to your house battery, ensuring they are always on, whether you’re on shore power or boondocking in the desert. 120V plug-in models are simpler to install but require an AC outlet and depend on your inverter or shore power. The battery backup on these is essential.
Second, placement is non-negotiable. Propane sinks. Your detector’s sensor must be mounted low to the ground, ideally within 6 to 12 inches of the floor. Under the sink is a perfect spot because it’s low and it’s close to potential leak sources. Never mount a propane detector, even a combo unit, near the ceiling. It simply won’t detect a leak until the entire bottom half of your rig has already filled with explosive gas.
Ultimately, a propane detector is not a place to cut corners. It’s a small investment in exchange for the safety of everyone and everything inside your mobile home. Go check the date on your current detector right now. If it’s more than five years old or is chirping, replace it today—it’s one of the most important and easiest upgrades you can make.
