Thermal Conductivity of Common Materials

What Is Thermal Conductivity?

Thermal conductivity quantifies a material’s ability to transfer heat. It indicates the speed at which heat moves from a warmer region to a cooler region. The units are watts per metre-kelvin (W/m·K). A high value means heat transfers rapidly, whereas a low value indicates slow heat transfer. Metals typically exhibit high thermal conductivity. Materials such as wood or plastics usually present low conductivity. This distinction impacts their use in applications such as cooking utensils, insulation and heat exchangers.

The concept is technical but has practical applications. For example, copper has a thermal conductivity of approximately 401 W/m·K and is employed in electrical wiring and cookware. Conversely, substances with low thermal conductivity serve as effective insulators in buildings and refrigeration systems. Thermal conductivity measurements assist engineers in selecting the appropriate material for a specific task.

List of Common Materials' Thermal Conductivity

The table below presents common materials with their typical thermal conductivity values:

Metals (High Thermal Conductivity)

Ceramics & Insulators

Polymers & Plastics

Semiconductors

Other Materials

• Copper: Approximately 400 W/m·K.
Copper is used in heat exchangers and cooking utensils because its thermal conductivity allows rapid heat transfer.

• Aluminium: Around 205 W/m·K.
Aluminium is common in kitchen products and building materials. It is lightweight and conducts heat efficiently.

• Iron: Roughly 80 W/m·K.
Iron is found in many construction components and machinery because its conductivity supports moderate heat transfer.

• Stainless Steel: About 15–20 W/m·K.
The lower conductivity of stainless steel renders it appropriate for appliances that require minimal heat transfer. It is often used in kitchen equipment and industrial parts.

• Glass: Typically around 1 W/m·K.
Glass is utilised in windows and insulating glazing. Its low thermal conductivity is pertinent to energy-saving designs.

• Wood: Between 0.1 and 0.2 W/m·K.
Wood is widely used as an insulator in construction, owing to its limited heat transfer capability.

• Plastic: Varies from approximately 0.1 to 0.5 W/m·K.
Plastics are employed in household items and electronic casings where restricted heat transfer is required.

• Ceramic: Approximately 1–30 W/m·K.
Ceramics are applied in cookware, electronics and high-temperature systems. For example, porcelain has a lower conductivity compared to other technical ceramics.

These values are approximate. In practice, purity, composition and temperature affect the measurements. Engineers refer to precise data and empirical evidence when choosing materials for heat transfer tasks.

Applications utilise thermal conductivity in various areas. In building insulation, low conductivity materials retain heat indoors during winter and restrict external heat during summer. In electronic devices, parts with high conductivity aid in dissipating heat to prevent thermal issues. Engineers and technicians use these data to guide material selection.

Conclusion

Thermal conductivity is a critical property that influences material selection for many applications. Metals such as copper and aluminium exhibit high thermal conductivity and are used in systems that require rapid heat transfer. In contrast, materials such as wood, plastics and glass possess low thermal conductivity and are used when minimised heat transfer is required. For more technical information and support, please check Stanford Advanced Materials (SAM).

Frequently Asked Questions

F: What does thermal conductivity indicate?
Q: It measures the rate at which heat is transferred through a material, thereby indicating its efficiency in conducting thermal energy.

F: Why is copper used in cookware?
Q: Copper’s high thermal conductivity ensures rapid and even distribution of heat.

F: How does low thermal conductivity benefit building insulation?
Q: A low thermal conductivity slows heat transfer, thereby retaining heat indoors during winter and excluding heat during summer.