The AirGuard is our plug-in CO & gas detector with a real-time digital display. Below — what it is, how it works, where to put it, and answers to every question we hear from customers.
The AirGuard is a plug-in home safety device that monitors the air for carbon monoxide (CO), natural gas, and propane. Unlike a standard CO alarm that only sounds once a dangerous level has already built up, the AirGuard has a real-time digital display that shows you exactly what's in the air, in parts per million (PPM), from 0 PPM upward.
Plug it into any standard US wall outlet, and within 30 seconds you can see live readings for CO, gas, and propane — plus temperature and humidity.
It's a plug-in unit about the size of a small air-freshener: a white case with a black front panel. The display shows numerical PPM readings, temperature, and humidity. Three indicator LEDs (POWER, FAULT, ALARM) and a single TEST button sit below the display.
Just the AirGuard unit (or two, four, or eight depending on the pack size you ordered). No batteries, no mounting hardware, no cables — it plugs directly into a standard outlet.
Safety authorities recommend one CO detector on every floor plus near every sleeping area. For most single-family homes that's 3 to 4 units. The 4-pack is our most popular option — 82% of customers choose it — because it covers the typical 2-story home with a finished basement.
A standard residential CO alarm is certified to UL 2034. That standard requires it to sound only once CO has reached 70 PPM sustained for 1 to 4 hours, or 150 PPM sustained for 10 to 50 minutes, or 400 PPM for 4 to 15 minutes. Below those thresholds, it stays silent by design.
The AirGuard has a digital display that updates in real time and shows readings starting at 0 PPM. You can see rising CO, natural gas, or propane long before it reaches a standard alarm's trigger point — so you have time to ventilate, turn off an appliance, or investigate before it becomes an emergency.
Three gases, all in one unit:
A standard CO detector won't catch a natural gas or propane leak — those fuels contain no CO until they ignite. The AirGuard covers all three.
Both. The digital display shows live PPM readings continuously, and an 85 dB audible alarm sounds when levels reach alarm thresholds. You don't need to be watching the display to be warned.
No. The sensor is calibrated specifically for carbon monoxide, natural gas, and propane — not steam, smoke, or cooking aerosols. You can use it in a kitchen without it triggering every time you use the oven or take a hot shower.
No. The AirGuard works completely standalone. No app, no Wi-Fi, no account, no setup — plug it in and it starts monitoring.
No. The AirGuard is plug-in and draws power from the wall outlet. No batteries to buy, no batteries to replace, no low-battery chirp at 3 am. The trade-off is that if the power goes out, the AirGuard will be offline — which is why it's important to also have a battery-backed UL-listed alarm installed per local code.
There's nothing to install. Plug it into any standard 120V US wall outlet at roughly eye level. No ladder, no tools, no electrician, no drilling, no mounting hardware. Most customers have it running in under 30 seconds.
When you first plug it in, the unit runs a brief self-test (the display flashes through a sequence, the LEDs light up, a short beep confirms the speaker works), then settles into its normal display showing the current PPM, temperature, and humidity readings.
Yes. The AirGuard plugs into any standard 120V US outlet. No drilling, no hardwiring, no landlord approval required, and nothing to remove or repair when you move out. Take it with you.
If the RV or cabin has a 120V US outlet (shore power hooked up, or an onboard inverter running), yes. The AirGuard is especially useful in RVs with propane appliances — the propane-detection capability is one of its three gas coverage modes.
Press and hold the TEST button on the front panel for about two seconds. The display will flash, the LEDs will sequence through, and the speaker will emit a short confirmation beep. If the self-test completes successfully, the unit returns to normal monitoring mode.
A self-test confirms that the speaker, LEDs, and electronics are working. It does not expose the sensor to actual gas — so passing a self-test is not the same as a calibrated chamber test. Plan to replace the unit periodically regardless.
Safety authorities recommend one CO detector on every level of your home plus near every sleeping area. For most single-family homes that's 3 to 4 units. Priority outlets for the AirGuard:
Roughly eye level — about 5 feet up — is the general recommendation. Carbon monoxide has a density similar to air and tends to distribute evenly in a room, so the exact height is not critical. Natural gas is lighter than air and rises; propane is heavier and sinks. An eye-level outlet is a reasonable compromise for a device that covers all three.
No. The AirGuard is designed to supplement — not replace — a certified residential CO alarm installed per local fire and building codes. Most US states and municipalities require a UL-listed CO alarm in residential buildings; the AirGuard does not satisfy that requirement.
Keep your existing UL-listed CO alarm installed. Install the AirGuard alongside it to add real-time visibility of concentrations below the UL-listed alarm's trigger threshold.
A standard CO alarm is designed to sound during an acute, high-concentration CO event. But the CDC documents that symptoms — headaches, dizziness, fatigue, impaired concentration — can begin at lower concentrations, particularly in children, older adults, and people with cardiovascular or respiratory conditions.
A real-time PPM display lets you see if your home is running at, say, a steady 15 or 20 PPM — below the alarm threshold but above background. That's information a standard yes/no alarm will never give you.
Treat it as a real CO event until proven otherwise:
Electrochemical CO sensors typically last between 5 and 10 years from manufacture. If you ever notice readings drifting, the unit failing its self-test, or behaviour that seems inconsistent with your other detectors, contact our support team — every AirGuard is covered by our lifetime device warranty.
Lifetime device warranty. Every AirGuard is covered for life against manufacturing defects. If the unit fails because of a defect in materials or workmanship at any point, we will replace it free of charge.
100-night trial. Try the AirGuard for 100 nights. If at any point you're not completely satisfied — for any reason — send it back. We refund every cent and cover the return shipping.
To start a return, just contact our support team with your order number.
Orders placed before 3 pm ET ship the same business day. Orders placed after 3 pm ET or over the weekend ship on the next business day.
Most US customers receive their AirGuard within 6 to 10 business days of placing the order. Delivery during peak holiday periods (Black Friday, Christmas) can run slightly longer.
No. Shipping is free on every AirGuard order within the United States.
At this time we ship within the United States only (including Alaska, Hawaii, and APO/FPO addresses). If you want to be notified when international shipping becomes available, send us a message and tell us your country — we'll email you when we go live there.
Visa, Mastercard, American Express, Discover, Apple Pay, Google Pay, and Shop Pay. All payments are processed through our secure payment gateway.
Most single-family homes cover every level and every sleeping area with the 4-pack. Free shipping. 100-night trial. Lifetime warranty.
Shop the AirGuard →If your question isn't answered above, our support team is standing by — live chat usually replies within a few minutes.