Prevent AHU Condensation and Corrosion: The Importance of TB1 Thermal Bridging Factor

Tired of unexpected AHU breakdowns and rising maintenance costs? Condensation and corrosion might be silently sabotaging your HVAC system. But there’s a proven solution: the TB1 thermal bridging factor. In this article, we’ll explain what it is, why it matters, and how it can transform your air handling system’s performance and reliability.

What is an AHU?

An Air Handling Unit (AHU) is a key component of any HVAC system. It conditions and circulates air throughout a building, ensuring comfort and indoor air quality. AHUs typically include:

• Fans: Circulate air through the system

• Coils: Heat or cool the air

• Filters: Remove dust and other contaminants

• Humidifiers/Dehumidifiers: Adjust humidity levels

While AHUs are essential, they’re vulnerable to issues like condensation and corrosion—especially without the right design features.

What Causes Condensation and Corrosion in AHUs?

Two major culprits affect AHU lifespan and performance:

• Condensation occurs when the surface of the AHU is cooler than the dew point, causing moisture to form. This leads to mold, mildew, and water damage.

• Corrosion follows, accelerated by moisture and temperature fluctuations, weakening metal components and shortening system life.

One overlooked but critical cause? Thermal bridging.

Understanding Thermal Bridging

Thermal bridging happens when heat moves through materials more easily than the surrounding insulation. In AHUs, this means temperature differences between the unit’s interior and exterior can cause unwanted condensation and heat loss.

TB Classification: What Does TB1 Mean?

The thermal bridging factor (TB) is a numerical value that indicates the level of heat transfer through a structure. A lower TB value means less heat transfer, while a higher TB value indicates more heat transfer. AHUs are typically classified into five categories based on their TB values:

• TB1 – 🔒 Best (Minimal heat transfer)
• TB2 – ✅ Good
• TB3 – ⚠️ Moderate
• TB4 – ❗ Poor
• TB5 – ❌ Worst (High heat transfer)

AHUs with a TB1 rating are designed to resist heat flow, preventing condensation and corrosion effectively.

Why TB1 Matters: The Benefits

A TB1-rated AHU doesn’t just look good on paper. It delivers real-world benefits:

• ✅ No More Drips or Mold: Prevents condensation on surfaces

• ✅ Longer System Life: Resistant to corrosion and material degradation

• ✅ Lower Energy Bills: Reduces heat loss and inefficiency

• ✅ Cleaner Indoor Air: Minimizes mold and contaminant growth

• ✅ Less Maintenance: Fewer repairs and replacements needed