First Alert Explosive Gas and Carbon Monoxide Alarm: Complete Product Guide and Reviews
In this guide: Everything you need to know about First Alert explosive gas and carbon monoxide detectors-including what First Alert combo gas/CO alarms detect, the full First Alert product lineup for gas and CO detection, product specifications and features, where to install First Alert gas and CO detectors in your home, how to install and maintain them, how First Alert compares to competitors, and answers to the most commonly asked questions about First Alert gas and CO detection products.
Understanding First Alert Gas and CO Detection Products
First Alert is one of the most recognisable names in home safety, best known for smoke detectors and fire extinguishers. However, the First Alert brand also offers a range of carbon monoxide detectors and-critically-a limited but important range of explosive gas and carbon monoxide combination detectors for homes with natural gas appliances.
Important clarification before we begin: First Alert's gas detection lineup focuses primarily on natural gas (methane) and carbon monoxide detection. First Alert does not currently manufacture a dedicated propane (LPG) combination detector. If you have propane appliances, you may need to look at brands like Safe-T-Alert or MTI Industries for propane-specific combination detectors. This guide covers First Alert's full gas and CO product range in detail.
What Does First Alert Explosive Gas and Carbon Monoxide Detection Cover?
The Two Gases First Alert Detects
| Gas | Chemical | Primary Danger | First Alert Product |
|---|---|---|---|
| Natural gas (methane) | CH₄ | Fire and explosion (lighter than air; rises to ceiling) | GCO1CN, First Alert gas alarms |
| Carbon monoxide (CO) | CO | Poisoning and death (colourless, odourless; produced by incomplete combustion) | GCO1CN, all First Alert CO detectors |
What First Alert Does NOT Detect
| Gas | Why First Alert Does Not Detect It | Alternative Brands |
|---|---|---|
| Propane (LPG) | Not included in First Alert's current natural gas calibration | Safe-T-Alert, MTI Industries |
| Butane | Not included in First Alert's current gas calibration | Safe-T-Alert, MTI Industries |
| Propane + CO (dual detection for RVs) | Not offered by First Alert | Safe-T-Alert 70-742-WT, MTI Industries 70-741-R-KD |
If your home or RV uses propane, First Alert's gas detectors are not the right choice for you. For propane detection, look to brands specifically calibrated for LPG.
First Alert Explosive Gas and CO Product Lineup (2026)
First Alert GCO1CN: Natural Gas and Carbon Monoxide Alarm
The First Alert GCO1CN is First Alert's flagship natural gas and carbon monoxide combination detector. This plug-in unit provides dual protection for homes with natural gas appliances.
Key Specifications
| Feature | Specification |
|---|---|
| Detects | Natural gas (methane) + Carbon monoxide |
| Power | 120V AC plug-in (no battery backup on this model) |
| Sensor technology | Metal oxide semiconductor (gas); electrochemical (CO) |
| Natural gas alarm threshold | Approximately 25% LEL |
| CO alarm threshold | 70 PPM (70–150 minutes); 400 PPM (4–15 minutes) |
| Audible alarm | 85 dB |
| Digital display | No (LED indicators only) |
| Plug type | Standard 120V AC; non-switched outlet required |
| Installation | Plug-in; no mounting hardware needed |
| Dimensions | Approximately 5 × 3 × 2 inches |
| Weight | Approximately 8 oz |
| Certifications | UL 1484 (natural gas); UL 2034 (CO) |
| Warranty | 5-year limited |
| Approximate price | $40–55 |
What Is Included in the Box
First Alert GCO1CN detector
User manual and warranty information
Quick-start guide
No mounting hardware (plug-in only)
Placement Recommendation
| Placement | Why |
|---|---|
| Near ceiling or upper wall | Natural gas is lighter than air; rises to ceiling |
| Within 10–20 feet of natural gas appliances | Early detection of gas leaks and CO from appliances |
| Near bedrooms | Audible alarm is within earshot for sleeping family members |
| On each level of multi-story homes | Coverage on all levels |
Pros and Cons
| Pros | Cons |
|---|---|
| ✅ Dual detection (natural gas + CO) in one device | ❌ No battery backup (power loss = no protection) |
| ✅ Easy plug-in installation | ❌ No digital display (LED indicators only) |
| ✅ Affordable dual-protection price point | ❌ Calibrated for natural gas only (not propane) |
| ✅ UL certified for both gas and CO | ❌ No interconnect capability |
| ✅ 5-year limited warranty | ❌ Only one AC plug (occupies outlet) |
First Alert GCO1CN vs Other First Alert CO-Only Models
First Alert offers several CO-only detectors that detect carbon monoxide but NOT explosive gas. These are suitable for homes with electric appliances or for layering with a separate gas detector.
First Alert CO400: Basic CO Detector
| Feature | Specification |
|---|---|
| Detects | Carbon monoxide only |
| Power | 9V battery powered |
| Display | No display; LED indicator |
| Alarm | 85 dB |
| Certification | UL 2034 |
| Approx. price | $20–30 |
First Alert CO615A: Digital CO Detector
| Feature | Specification |
|---|---|
| Detects | Carbon monoxide only |
| Power | 9V battery powered |
| Display | Digital CO PPM display |
| Alarm | 85 dB; peak level memory |
| Certification | UL 2034 |
| Approx. price | $35–50 |
First Alert CO710: 10-Year Sealed Battery CO Detector
| Feature | Specification |
|---|---|
| Detects | Carbon monoxide only |
| Power | 10-year sealed lithium battery (no replacement needed) |
| Display | Digital CO PPM display |
| Alarm | 85 dB; voice alert |
| Certification | UL 2034 |
| Approx. price | $40–60 |
Comparison: First Alert CO Detectors vs GCO1CN
| Feature | GCO1CN (Gas + CO) | CO400 | CO615A | CO710 |
|---|---|---|---|---|
| Natural gas detection | ✅ | ❌ | ❌ | ❌ |
| Carbon monoxide detection | ✅ | ✅ | ✅ | ✅ |
| Propane detection | ❌ | ❌ | ❌ | ❌ |
| Display | LED indicators | LED indicator | Digital PPM | Digital PPM |
| Power | 120V AC | 9V battery | 9V battery | 10-year sealed |
| Price | $40–55 | $20–30 | $35–50 | $40–60 |
First Alert Smoke + CO Combination Detectors (No Gas Detection)
First Alert offers smoke and carbon monoxide combination detectors, but these do NOT detect explosive gas. These are listed here for completeness, but they should not be used as a substitute for a gas detector in homes with gas appliances.
| Product | Detects | Power | Display | Price | Note |
|---|---|---|---|---|---|
| First Alert SCO7CN | Smoke + CO | 120V AC + battery backup | Digital | $60–80 | Voice alarm; no gas detection |
| First Alert SC9120B | Smoke + CO | 120V AC + battery backup | LED | $45–65 | Hardwire; no gas detection |
| First Alert P1010 | Smoke + CO | 10-year sealed battery | LED | $50–65 | 10-year battery; no gas detection |
None of these smoke + CO detectors detect natural gas or propane. They are for fire and CO protection only.
Where to Install First Alert Gas and CO Detectors
Natural Gas Detector Placement
First Alert natural gas detectors must be mounted high because natural gas (methane) is lighter than air and rises toward the ceiling:
| Placement Location | Why This Location |
|---|---|
| Within 10–20 feet of natural gas appliances | Near furnaces, water heaters, stoves, dryers |
| Near ceiling or on upper wall (within 12 inches of ceiling) | Natural gas rises; detector must be in the accumulated gas zone |
| Near the natural gas meter | Early detection of supply-side leaks |
| Outside sleeping areas | Audible alarm wakes sleepers |
| On each level of multi-story homes | Coverage on all levels |
Do NOT place natural gas detectors:
Near windows, doors, or vents (airflow dilutes gas)
Near ceiling fans or HVAC returns (airflow disperses gas)
Behind furniture (blocks airflow to detector)
In unheated spaces where temperature extremes may affect sensor
Carbon Monoxide Detector Placement
First Alert CO detectors can be mounted at any height because CO mixes evenly with air:
| Placement Location | Why This Location |
|---|---|
| Outside each sleeping area | Audible alarm wakes sleepers |
| On each level of the home | CO can accumulate anywhere |
| Within 10–20 feet of fuel-burning appliances | Near furnaces, water heaters, gas stoves |
| Near attached garages | Vehicle exhaust can enter home |
Complete Coverage for Homes with Natural Gas
| Level | Detectors Needed | Recommended First Alert Product |
|---|---|---|
| Basement | Natural gas detector (high) + CO detector | GCO1CN (gas+CO) + CO710 (CO only) |
| Main floor | Natural gas detector (high) + CO detector | GCO1CN (gas+CO) + CO710 (CO only) |
| Upper floors | CO detector outside each bedroom | CO710 or CO615A |
| Near garage | CO detector near garage entrance | CO710 or CO400 |
Installation: How to Install the First Alert GCO1CN
Step-by-Step Installation
| Step | Action | Details |
|---|---|---|
| 1 | Choose the right outlet | Use a standard 120V AC outlet that is NOT controlled by a wall switch; the detector must remain powered at all times |
| 2 | Plan placement | Near ceiling or upper wall (natural gas rises); within 10–20 feet of gas appliances; near sleeping areas |
| 3 | Insert the plug | Push the detector firmly into the outlet until it is fully seated |
| 4 | Allow warm-up time | Allow 2–5 minutes for the sensor to stabilise after power-on |
| 5 | Test the detector | Press and hold the test button; both gas and CO alarms should sound |
| 6 | Record the installation date | Write the date on the detector or in your records for maintenance tracking |
What NOT to Do
| Do NOT | Why |
|---|---|
| Plug into an outlet controlled by a wall switch | Detector would turn off when switch is off |
| Use an extension cord | Loose connections can cause power interruptions |
| Place behind furniture | Furniture blocks airflow to the sensor |
| Place near windows, vents, or ceiling fans | Airflow disperses gas before it reaches the sensor |
| Install near cooking appliances (within 5 feet) | Cooking fumes can trigger false alarms |
Maintenance and Testing
Monthly Testing
Test both detection systems every month:
| Test | How to Perform |
|---|---|
| Test button | Press and hold the test button until both alarms sound (both gas and CO alarm patterns should activate) |
| Gas alarm test | Some units allow a small amount of butane lighter gas to be introduced near the sensor (check manual first; do NOT use an open flame) |
| CO sensor test | Press test button to confirm CO alarm sounds; CO sensor is tested via the test button on most models |
Annual Maintenance
| Task | Frequency | Details |
|---|---|---|
| Vacuum the detector | Every 6 months | Use the brush attachment to remove dust from vents; do not insert objects into sensor openings |
| Check power connection | Monthly | Ensure the detector is firmly plugged in; check outlet is working |
| Check for damage | Monthly | Look for cracks, discolouration, or other signs of damage |
| Review expiration date | Annually | Replace per manufacturer schedule (typically 5–7 years) |
Replacement Schedule
| Model | Recommended Lifespan | Replacement Trigger |
|---|---|---|
| First Alert GCO1CN | 5–7 years | End-of-life indicator; reached rated lifespan |
| First Alert CO detectors | 5–7 years | End-of-life indicator; reached rated lifespan |
| Batteries (battery-powered models) | Replace annually | Low-battery chirp |
First Alert GCO1CN vs Competitors
How First Alert Compares
| Feature | First Alert GCO1CN | Kidde KN-COEG-3 Nighthawk | Safe-T-Alert (Propane) |
|---|---|---|---|
| Natural gas detection | ✅ | ✅ | ❌ |
| Propane detection | ❌ | ❌ | ✅ |
| CO detection | ✅ | ✅ | ✅ |
| Power | 120V AC plug-in | 120V AC plug-in | 12V DC hardwired |
| Digital display | No (LED only) | ✅ (CO PPM display + gas bar) | LED indicators only |
| Certifications | UL 1484 + UL 2034 | UL 1484 + UL 2034 | UL 1484 + UL 2034 |
| Warranty | 5-year | 5-year | 5-year |
| Price | $40–55 | $45–65 | $70–100 |
| Best for | Natural gas homes; budget | Natural gas homes; feature-rich | Propane homes and RVs |
When to Choose First Alert vs Competitors
| Situation | Recommended Product | Why |
|---|---|---|
| Home with natural gas; budget priority | First Alert GCO1CN | Affordable; dual detection; reliable brand |
| Home with natural gas; want display | Kidde KN-COEG-3 Nighthawk | Digital CO PPM display; slightly higher price |
| Home with propane appliances | Safe-T-Alert 70-742-WT | Propane calibration; 12V DC for RVs or hardwired homes |
| RV with propane | Safe-T-Alert 70-742-WT | 12V DC hardwired; propane calibration; CO detection |
| Home with both propane and natural gas | First Alert GCO1CN (natural gas) + Safe-T-Alert (propane) | Separate detectors for each fuel type |
Frequently Asked Questions
Q1: Does the First Alert GCO1CN detect propane?
No-the First Alert GCO1CN is calibrated specifically for natural gas (methane) and carbon monoxide. It does not detect propane, butane, or other combustible gases. If your home or RV uses propane, you need a detector specifically calibrated for propane, such as the Safe-T-Alert 70-742-WT or MTI Industries 70-741-R-KD.
Q2: Does the First Alert GCO1CN have a battery backup?
No-the First Alert GCO1CN does not have a battery backup. It is powered solely by 120V AC. If power is lost, the detector does not function. For homes with frequent power outages, consider:
A battery-powered CO detector as backup (First Alert CO710)
A uninterruptible power supply (UPS) for critical detectors
A hardwired detector with battery backup (Kidde KN-COEG-3 has no battery backup either)
Q3: Can the First Alert GCO1CN be mounted on the wall?
The GCO1CN is primarily designed as a plug-in detector and does not include mounting hardware. It can be used in the plug-in position (typically on a lower outlet) and will detect natural gas accumulating near the ceiling, as the gas will eventually reach floor level in an enclosed room. However, for optimal natural gas detection, a detector positioned near the ceiling is more effective. Some users mount the GCO1CN using a short extension cord or by securing it near the ceiling using adhesive strips-but this is not the manufacturer's recommended installation.
Q4: How loud is the First Alert GCO1CN alarm?
The First Alert GCO1CN produces an 85 dB audible alarm at 10 feet. This is comparable to a smoke detector and is loud enough to wake most sleeping adults from a normal sleep. For people with hearing impairments, some jurisdictions require strobe light detectors as an additional alert.
Q5: Can I use the First Alert GCO1CN in a garage?
The First Alert GCO1CN is designed for indoor residential use and is not rated for use in unconditioned outdoor or garage environments. Temperature extremes, moisture, and vehicle exhaust in garages can affect sensor accuracy and cause false alarms. For garages with natural gas heating, consider a detector rated for that environment, or use a separate battery-powered CO detector (garage vehicles produce CO, not natural gas).
Q6: How do I know if my First Alert detector needs to be replaced?
| Sign | Meaning | Action |
|---|---|---|
| End-of-life chirp | Detector has reached rated lifespan | Replace immediately |
| Constant false alarms | Sensor contaminated or failed | Replace; check for contaminants |
| No response to test button | Power issue or detector failure | Check power; if no response, replace |
| Reached 5–7 years old | Sensor lifespan expired | Replace proactively |
| Physical damage | Detector compromised | Replace immediately |
Q7: What is the difference between the First Alert GCO1CN and the Kidde KN-COEG-3?
| Feature | First Alert GCO1CN | Kidde KN-COEG-3 Nighthawk |
|---|---|---|
| Natural gas detection | ✅ | ✅ |
| CO detection | ✅ | ✅ |
| Digital display | ❌ (LED only) | ✅ (CO PPM + gas level bar graph) |
| Gas sensor test | Button only | Button only |
| Plug-in | ✅ | ✅ |
| Battery backup | ❌ | ❌ |
| Certification | UL 1484 + UL 2034 | UL 1484 + UL 2034 |
| Warranty | 5-year | 5-year |
| Price | $40–55 | $45–65 |
Choose the Kidde if you want a digital display showing CO concentration. Choose the First Alert if you want a more affordable option with the same core protection.
The Bottom Line: First Alert Gas and CO Detection
The First Alert GCO1CN is a solid, affordable option for homeowners with natural gas appliances who want dual gas and CO protection in a single device. First Alert's reputation for quality smoke detectors and fire safety extends to its gas detection lineup, making the GCO1CN a trustworthy choice for natural gas homes.
Key recommendations for 2026:
| Situation | Recommended First Alert Product | Approx. Cost | Notes |
|---|---|---|---|
| Home with natural gas; single detector | First Alert GCO1CN | $40–55 | Best value dual gas + CO protection |
| Home with natural gas; want display | Kidde KN-COEG-3 Nighthawk | $45–65 | Digital CO PPM display; compatible alternative |
| Home with propane (not First Alert) | Safe-T-Alert 70-742-WT | $70–100 | First Alert does not offer propane detection |
| Home with electric appliances only | First Alert CO710 | $40–60 | 10-year sealed battery; CO protection only |
| Layered protection (natural gas home) | GCO1CN per floor + CO710 in bedrooms | $80–115 | Comprehensive coverage |
Action checklist:
✅ Identify your fuel type (natural gas vs propane)
✅ Install First Alert GCO1CN if you have natural gas
✅ If you have propane, choose Safe-T-Alert instead (First Alert does not offer propane)
✅ Place natural gas detectors near ceiling (First Alert GCO1CN)
✅ Place CO detectors outside sleeping areas
✅ Test both detection systems monthly
✅ Replace detectors every 5–7 years
First Alert provides reliable, affordable gas and CO protection for natural gas homes. For propane applications, look to specialist brands. Either way, the right detector is always better than no detector-and the right combination of detectors is better still.
Last updated: July 2026
Disclaimer: This guide provides general information about First Alert explosive gas and carbon monoxide detection products for educational purposes. Product specifications, features, and pricing are subject to change. Always verify current information from the manufacturer's official documentation before purchasing. First Alert products are certified to relevant US standards (UL 1484, UL 2034). Requirements and codes vary by jurisdiction. Installation should follow manufacturer guidelines and applicable local codes. In case of alarm, evacuate immediately and call emergency services.
