Choosing the right gas sensor is one of the most important decisions when selecting a gas detector. The two most widely used technologies today are electrochemical sensors and infrared (IR) sensors. Both detect gases, but they work in completely different ways and offer different levels of accuracy, stability, and long-term performance.

This guide explains the differences in clear, simple language so you can choose the best option for home safety, industrial use, or professional gas monitoring.

---

1. What Are Electrochemical Gas Sensors?

Electrochemical sensors are used to detect toxic gases such as:

• Carbon monoxide (CO)

• Hydrogen sulfide (H₂S)

• Nitrogen dioxide (NO₂)

• Sulfur dioxide (SO₂)

• Oxygen (O₂) concentration

These sensors generate an electrical current when gas molecules react with chemicals inside the sensor.

How Electrochemical Sensors Work

1. Target gas enters the sensor

2. Gas molecules react with an electrolyte

3. This reaction produces an electrical current

4. Current strength = gas concentration

Advantages

• Very high accuracy for toxic gases

• Strong gas selectivity

• Low power consumption

• Affordable for portable detectors

• Ideal for confined space and industrial safety

Limitations

• Lifespan usually 2–3 years

• Sensitive to extreme temperatures

• Specific to certain gases (not universal)

Electrochemical sensors remain the most reliable choice for toxic gas detection.

---

2. What Are Infrared (IR) Gas Sensors?

Infrared gas sensors detect gases that absorb infrared light. They are widely used for:

• CO₂ (carbon dioxide)

• Hydrocarbon gases (methane, propane, etc.)

• Refrigerants

• Flammable gases in industrial environments

How Infrared Sensors Work

1. IR light passes through the air inside the sensor

2. Gas molecules absorb specific IR wavelengths

3. A detector measures how much light was absorbed

4. The device calculates gas concentration

Advantages

• Extremely stable and long lifespan

• Not affected by oxygen levels

• Excellent for CO₂ and hydrocarbons

• Low maintenance

• Fast response time

• Immune to sensor poisoning

Limitations

• Cannot detect gases that do not absorb IR (e.g., H₂S, CO in simple IR systems)

• More expensive than electrochemical sensors

• Larger in size (in most designs)

IR sensors dominate CO₂ detection and hydrocarbon leak monitoring.

---

3. Accuracy Comparison: Which Sensor Is More Accurate?

⭐ Electrochemical Sensors: Best for Toxic Gas Accuracy

Electrochemical sensors provide industry-leading accuracy for gases like CO, H₂S, and O₂. Their chemical reaction is highly selective, giving precise readings even at very low concentrations (ppm level).

Accuracy Highlights:

• Excellent for personal safety monitoring

• Very precise at low gas levels

• Minimal cross-interference

For toxic gases, electrochemical sensors are the most accurate option.

---

⭐ Infrared Sensors: Best for CO₂ and Hydrocarbon Accuracy

Infrared technology is extremely accurate for gases that strongly absorb IR spectra:

• CO₂

• Methane

• Propane

• Refrigerants

IR sensors are known for:

• Very stable measurements

• No sensor drift

• Long-term calibration stability

• High accuracy for LEL (lower explosive limit) monitoring

For CO₂ or flammable hydrocarbon detection, IR sensors are more accurate than electrochemical or catalytic types.

---

4. Side-by-Side Comparison Table

---

5. Which Sensor Should You Choose?

✔ Choose Electrochemical Sensors if you need to detect:

• Carbon monoxide

• Hydrogen sulfide

• Oxygen levels

• Nitrogen dioxide

• Sulfur dioxide

Best for:

• Confined space entry

• Industrial toxic gas detection

• Portable 4-in-1 gas detectors

• Personal safety and PPE devices

---

✔ Choose Infrared Sensors if you need to detect:

• CO₂

• Hydrocarbon gases (CH₄, C₃H₈, etc.)

• Refrigerants

• Combustible gas LEL levels

Best for:

• HVAC & indoor air quality monitoring

• Industrial hydrocarbon leak detection

• Greenhouses & enclosed rooms

• Fixed gas detection systems

---

6. Conclusion: Which Technology Is More Accurate Overall?

There is no single “winner”—each sensor is more accurate for its intended gas type:

• Electrochemical = most accurate for toxic gases

• Infrared = most accurate for CO₂ and hydrocarbons

For the highest safety and reliability, many professional gas detectors combine both technologies in one device.

• Share on:
• WhatsApp
• Deel
• X
• Pin it
• Messenger
• Email

---