In building HVAC systems, the choice of duct material directly affects the system's insulation performance, energy consumption, and service life. Currently, fiberglass ducts and composite ducts are widely used in engineering projects. The two differ significantly in structural form, performance, and applicable scenarios. This article will compare the performance of fiberglass ducts and composite ducts from multiple dimensions, providing a systematic analysis to offer a reference for project selection.

I. Material Composition and Structural Comparison

1. Structural Characteristics of Fiberglass Ducts

Fiberglass ducts are typically made primarily of glass fiber, integrally formed from high-density fiberglass sheets. Their internal structure is porous fiber, and the outer surface is often covered with aluminum foil or other protective layers, combining the functions of ductwork and insulation.

This structure gives fiberglass ducts natural advantages in insulation and sound absorption, making them widely used in HVAC systems.

2. Structural Composition of Composite Ducts

Composite ducts are generally composed of multiple layers of materials. Common structures include:

Inner and outer metal outer layers

Intermediate insulation core material (such as phenolic resin, polyurethane, etc.)

Composite ducts emphasize structural strength and overall stability, making them suitable for applications requiring high mechanical strength.

II. Comparison of Thermal Insulation Performance

The two types of ducts achieve their thermal insulation performance differently:

Fiberglass ducts: Rely on a large number of still air layers within the fiberglass structure for insulation, resulting in stable thermal conductivity.

Composite ducts: Primarily rely on the insulation performance of the intermediate core material; the overall effect is significantly affected by the type of material.

In conventional HVAC systems, fiberglass ducts, being themselves insulation materials, avoid secondary insulation construction, resulting in better overall heat loss control.

III. Comparison of Sound Insulation and Noise Reduction Performance

Sound Absorption Advantages of Fiberglass Ducts

The porous fiber structure inside fiberglass ducts effectively absorbs fan noise and airflow noise, significantly reducing system operating noise.

Sound Insulation Performance of Composite Ducts

Composite ducts themselves have limited sound absorption performance, typically requiring additional silencers or sound-absorbing sections to meet higher noise reduction requirements.

IV. Fire Resistance Performance Differences

Fiberglass Duct Fire Resistance

Fiberglass is an inorganic material and is inherently non-combustible. Under fire conditions, fiberglass ducts will not contribute to combustion or release significant heat, exhibiting good fire resistance stability.

Composite Duct Fire Resistance

The fire resistance performance of composite ducts primarily depends on the core material type. Some organic core materials may experience performance changes under high-temperature conditions and require fire resistance testing before application in areas with high fire safety requirements.

V. Weight and Construction Performance Comparison

**Fiberglass Duct Construction Characteristics:**

Lightweight, reducing building load

Can be cut and assembled on-site

High installation efficiency

**Composite Duct Construction Characteristics:**

High structural strength

Good rigidity, but relatively heavy

Higher requirements for hoisting and support structures

VI. Comparison of Applicable Scenarios

| Application Scenarios | Fiberglass Duct | Composite Duct |

| ------- | ------ | ------ |

| Commercial Buildings | ✔ Commonly Used | ✔ Available |

| Public Buildings | ✔ Suitable | ✔ Suitable |

| Hospitals, Schools | ✔ Preferred | △ Noise Reduction Required |

| Noise-Sensitive Areas | ✔ Significant Advantages | △ Auxiliary Measures |

| High-Intensity Industrial Environments | △ General | ✔ More Suitable |

VII. Comprehensive Performance Comparison Summary

Through the performance comparison of fiberglass ducts and composite ducts, it can be seen that:

Fiberglass ducts: Excellent thermal insulation and sound absorption properties, lightweight, and easy to install.

Composite ducts: High structural strength, suitable for projects with high rigidity requirements.

In actual projects, the appropriate type should be selected based on building type, noise requirements, fire rating, and construction conditions, rather than comparing a single indicator.

Fiberglass ducts and composite ducts each have clear application advantages. Through scientific design and reasonable configuration, they can not only improve the overall performance of the HVAC system but also help reduce operating energy consumption and maintenance costs.