How to Distinguish Pure Aluminum Reflective Film from Metallized Reflective Film
In underfloor heating systems, reflective film is an important insulation component that reduces downward heat radiation and improves heating efficiency. However, pure aluminum reflective film and metallized reflective film have significant differences in material structure, thermal performance, durability, and application value.
Difference in Material Structure
The biggest difference between the two types of reflective films is the aluminum layer structure.
Pure aluminum reflective film uses aluminum foil as the main reflective layer. The aluminum layer is a continuous metal layer with relatively high thickness, providing strong infrared reflection performance and stable long-term performance.
Metallized reflective film is produced by vacuum coating aluminum onto a plastic substrate such as PET or PE film. The aluminum layer is extremely thin and attached to the surface of the polymer film.
The main difference is that pure aluminum film contains a real aluminum foil layer, while metallized film only has a thin aluminum coating.
Appearance Identification Method
From appearance, both materials may look bright and metallic, but there are some differences:
Pure aluminum reflective film usually has a stronger metallic texture, with a brighter mirror-like surface and better light reflection. The aluminum layer feels more solid and less like a plastic film.
Metallized reflective film often has a softer appearance because the aluminum coating is extremely thin. Under strong light, the surface may show more transparency or uneven reflection.
However, appearance alone cannot completely determine the material, because high-quality metallized films can also have a very bright surface.
Thickness and Mechanical Performance
Pure aluminum reflective film generally has a thicker metal layer, giving it:
Better tear resistance
Higher mechanical strength
Better resistance to construction damage
More stable reflective performance
Metallized film relies mainly on the plastic substrate for strength. The aluminum coating may be damaged by scratching, folding, or long-term environmental exposure, reducing reflective efficiency.
Difference in Reflectivity Performance
The purpose of reflective film in underfloor heating is to reflect infrared radiation generated by heating pipes.
Pure aluminum has naturally high infrared reflectivity, allowing more radiant heat to be reflected upward toward the floor surface.
Metallized film can also provide reflective performance, but because the aluminum coating is much thinner, its reflection efficiency and long-term stability are usually lower than pure aluminum foil products.
For high-efficiency underfloor heating systems, especially low-temperature heating applications, pure aluminum reflective film generally provides more reliable thermal performance.
Durability During Heating Cycles
Underfloor heating systems experience repeated temperature changes during operation. The reflective layer must maintain performance over many heating cycles.
Pure aluminum reflective film has better oxidation resistance and aging resistance, making it suitable for long-term applications.
Metallized films may experience aluminum layer oxidation, cracking, or separation from the substrate after long-term exposure to moisture, heat, or mechanical stress.
Simple Testing Methods
Several simple methods can help identify the material:
Folding test: Pure aluminum foil tends to leave permanent folding marks, while metallized film behaves more like plastic film and may recover slightly.
Scratching test: If the surface coating is easily removed and reveals a plastic base layer, it is likely metallized film.
Tearing observation: Pure aluminum film shows metallic fracture characteristics, while metallized film usually exposes a polymer layer.
For professional identification, aluminum layer thickness testing and material analysis equipment provide more accurate results.
Selection Recommendations for Underfloor Heating
When selecting reflective film for underfloor heating projects, consider:
High-efficiency residential heating systems: Prefer pure aluminum reflective film for better thermal stability and durability.
Standard insulation applications: Quality metallized reflective film may be acceptable when cost requirements are higher.
Commercial buildings and long-life heating projects: Choose products with stable aluminum layers, reliable reflectivity, and verified performance data.
Conclusion
The key difference between pure aluminum reflective film and metallized reflective film lies in the thickness and structure of the aluminum layer. Pure aluminum reflective film provides stronger reflection performance, better durability, and more stable long-term heat management, while metallized film offers a more economical solution.
For underfloor heating systems where energy efficiency and service life are important, pure aluminum reflective film is generally the more reliable choice.
References
EN 1264 — Water based surface embedded heating and cooling systems
ISO 11855 — Building environment design of radiant heating and cooling systems
ASTM C1313 — Standard Specification for Sheet Radiant Barriers for Building Construction
ASHRAE Handbook — HVAC Systems and Equipment, Radiant Heating and Cooling Systems
Manufacturer technical specifications for radiant barrier and underfloor heating insulation materials
