Thermal conductivity is one of the most important specifications when selecting aerogel felt for an industrial insulation project. It directly affects heat loss, insulation thickness, equipment surface temperature and long-term energy consumption.

However, comparing aerogel insulation products based on a single thermal conductivity value can be misleading. Test temperature, product density, thickness, moisture exposure and installation quality can all affect actual thermal performance.

This guide explains how aerogel felt thermal conductivity is measured, why it changes with temperature and what buyers should check before placing an order.

What Is Aerogel Felt?

Aerogel felt, also known as an aerogel blanket, is a flexible insulation material made by combining silica aerogel with a fibrous reinforcement layer.

Silica aerogel has a highly porous nanoscale structure that limits heat transfer through solid conduction, gas movement and convection. The fiber reinforcement makes the otherwise fragile aerogel easier to roll, cut and install around pipes, tanks, valves and industrial equipment.

Compared with many conventional insulation materials, aerogel thermal insulation felt can achieve the required thermal performance with a thinner insulation layer. This makes it especially useful when installation space is limited.

What Does Thermal Conductivity Mean?

Thermal conductivity describes how easily heat passes through a material. It is normally expressed in:

W/(m·K)

A lower value means that the material transfers less heat and therefore provides better insulation at the same thickness.

For example:

A material with a thermal conductivity of 0.020 W/(m·K) provides better insulation than one rated at 0.040 W/(m·K) when both are tested under the same conditions.

If two materials need to achieve the same thermal resistance, the material with lower thermal conductivity can generally use a thinner insulation layer.

Thermal conductivity is commonly represented by the Greek letter λ, or lambda.

Typical Thermal Conductivity of Aerogel Felt

Depending on its formulation, density and operating temperature, industrial silica aerogel felt commonly has a thermal conductivity of approximately:

0.012–0.020 W/(m·K) at or near room temperature

This is a general reference range rather than a guaranteed value for every product.

For example, the website's aerogel blanket thermal insulation is listed with a thermal conductivity of approximately 0.012–0.018 W/(m·K) at 25°C, depending on the selected grade.

Another 10mm aerogel blanket for pipe insulation provides representative conductivity data at different temperatures:

These figures show an important point: the thermal conductivity of aerogel felt is not constant. It generally increases as the mean operating temperature rises.

Buyers should request a complete thermal conductivity curve rather than relying only on the room-temperature value.

Why Does Aerogel Felt Have Low Thermal Conductivity?

Heat can move through insulation in several ways:

Conduction through the solid structure

Conduction through the gas inside the pores

Convection within larger air spaces

Thermal radiation

Aerogel felt reduces these heat-transfer mechanisms through its nanoscale pore structure.

Limited Solid Conduction

Silica aerogel contains a very small amount of solid material compared with its total volume. The complex network also creates a long and indirect path for heat to travel through the solid structure.

Reduced Gas Conduction

The pores inside aerogel are extremely small. This restricts the movement and collision of gas molecules, reducing heat transfer through the air contained within the material.

Suppressed Convection

Because the pores are nanoscale, air cannot circulate freely inside the aerogel structure. This significantly limits convective heat transfer.

Reduced Thermal Radiation

Some high-temperature aerogel formulations include opacifiers or other components designed to reduce radiative heat transfer. This becomes increasingly important as operating temperature rises.

Thermal Conductivity Changes with Temperature

A room-temperature thermal conductivity value does not fully describe how insulation will perform on a hot pipeline or industrial furnace.

As temperature increases:

Gas conduction generally increases

Radiative heat transfer becomes more significant

The effective thermal conductivity of the insulation rises

A greater thickness may be required to achieve the target surface temperature

For this reason, thermal insulation calculations should use the conductivity value at the expected mean temperature, not simply the conductivity at 25°C.

The mean temperature is commonly estimated as:

Tm=Th+Tc2T_m = \frac{T_h + T_c}{2}

Where:

TmT_m = mean temperature

ThT_h = hot-side temperature

TcT_c = cold-side temperature

For a pipe operating at 300°C with an expected insulation outer-surface temperature of 40°C, the approximate mean temperature would be:

Tm=300+402=170∘CT_m = \frac{300 + 40}{2} = 170^\circ C

The thermal conductivity used in the initial calculation should therefore be based on data close to 170°C-not the value measured at room temperature.

A professional thermal calculation may require iterative evaluation because the surface temperature, thermal conductivity and total heat loss influence one another.

Thermal Conductivity vs Thermal Resistance

Thermal conductivity and thermal resistance are related, but they are not the same specification.

Thermal resistance indicates how strongly a particular thickness resists heat flow. For a flat, uniform layer, it can be estimated using:

R=dλR = \frac{d}{\lambda}

Where:

RR = thermal resistance in m²·K/W

dd = insulation thickness in metres

λ\lambda = thermal conductivity in W/(m·K)

For example, a 10mm aerogel felt with a thermal conductivity of 0.020 W/(m·K) would have an approximate thermal resistance of:

R=0.0100.020=0.50 m2\cdotpK/WR = \frac{0.010}{0.020}=0.50\ \text{m}^2\text{·K/W}

If the same material's conductivity rises to 0.028 W/(m·K) at a higher temperature, its calculated resistance becomes:

R=0.0100.028≈0.36 m2\cdotpK/WR = \frac{0.010}{0.028}\approx0.36\ \text{m}^2\text{·K/W}

This simplified example demonstrates why both thickness and operating-temperature conductivity must be considered.

Actual pipe and equipment insulation calculations also need to account for geometry, surface emissivity, ambient conditions, wind speed and outer cladding.

What Affects Aerogel Felt Thermal Conductivity?

1. Operating Temperature

Thermal conductivity usually increases as the mean temperature rises. Always request conductivity data covering the project's actual operating range.

2. Product Density

Density affects the balance between solid conduction and pore structure. A higher-density product is not automatically a better insulator, although it may offer improved mechanical strength.

3. Aerogel Content

Products sold under the general name "aerogel felt" may contain different amounts of silica aerogel. Lower aerogel content can reduce thermal performance, even when the products appear similar.

4. Fiber Reinforcement

The type, structure and density of the reinforcing fibers affect flexibility, mechanical strength and heat transfer through the finished blanket.

5. Moisture Exposure

Water has a much higher thermal conductivity than still air. When conventional fibrous insulation absorbs moisture, its thermal performance can deteriorate significantly.

Hydrophobic aerogel felt helps resist liquid-water penetration. The website's aerogel thermal insulation felt, for example, is listed with a hydrophobic rate of at least 99.6%.

However, hydrophobic does not mean that an entire insulation system is automatically waterproof. Joints, penetrations and external cladding must still be properly sealed.

6. Compression

Excessive compression can change the thickness and internal structure of the blanket. If a nominal 10mm layer is compressed to 7mm during installation, the final thermal resistance will be lower because the installed thickness has been reduced.

The material should be secured firmly without unnecessary crushing.

7. Seams and Gaps

Poorly fitted joints can create thermal bridges and allow heat to bypass the insulation layer. Even a low-conductivity material cannot compensate for large gaps or poorly designed terminations.

Staggered joints are recommended when multiple layers are installed.

Why Thickness Still Matters

Low thermal conductivity does not eliminate the need for sufficient insulation thickness.

Common aerogel felt thicknesses include:

3mm

5mm

6mm

8mm

10mm

Multiple layers can be used when the project requires greater thermal resistance.

The correct thickness depends on:

Equipment operating temperature

Required outer-surface temperature

Allowable heat loss

Pipe or equipment dimensions

Ambient temperature

Indoor or outdoor installation

Wind speed

External cladding

Personnel-protection requirements

Available installation space

Aerogel felt is particularly valuable where thick conventional insulation cannot be installed because of limited clearance, closely spaced pipelines or restricted equipment access.

Aerogel Felt vs Conventional Insulation

The following values are general reference ranges at or near room temperature. Actual values vary by product grade and test conditions.

The comparison does not mean aerogel is the best choice for every project. Traditional materials may provide a lower initial material cost and can be suitable where there is enough installation space.

Aerogel felt is often considered when a project requires:

Reduced insulation thickness

Lower heat loss within limited space

Good resistance to moisture

Easier installation around complex shapes

Reduced insulation volume

Performance across a wide temperature range

Common Industrial Applications

High-Temperature Pipelines

Aerogel felt can be wrapped around steam, process and petrochemical pipelines. Its low conductivity helps control heat loss without requiring an excessively thick insulation layer.

Oil and Gas Facilities

It is used for pipelines, vessels and processing equipment where space, weather exposure and corrosion under insulation are important concerns.

LNG and Cryogenic Systems

Suitable grades can be considered for low-temperature pipelines and equipment. The material selection must be based on the specified minimum operating temperature and system design.

Power Generation

Aerogel insulation can be applied to turbines, boilers, steam systems and other equipment where energy efficiency and surface-temperature control are required.

Industrial Tanks and Vessels

Flexible blankets can conform to curved surfaces and complex equipment profiles more easily than some rigid insulation products.

Marine and Offshore Equipment

Limited installation space and moisture exposure make low-conductivity, hydrophobic insulation attractive for certain shipboard and offshore applications.

How to Compare Thermal Conductivity Data

When reviewing supplier data sheets, check whether the values were measured under comparable conditions.

Ask the supplier to confirm:

Test standard

Mean test temperature

Product thickness

Product density

Measurement direction

Sample conditioning

Moisture condition

Test laboratory or report source

Conductivity tolerance

Whether the figures are typical or guaranteed values

Two suppliers may state different conductivity values because one reports performance at 25°C while another uses a higher mean temperature. The lower number is not necessarily evidence of a better product unless the test conditions are equivalent.

Information to Provide When Requesting a Quotation

To receive an appropriate product recommendation, buyers should provide:

Intended application

Normal operating temperature

Maximum and minimum temperatures

Pipe diameter or equipment dimensions

Required surface temperature

Maximum permitted heat loss

Available insulation space

Indoor or outdoor environment

Exposure to rain, chemicals or mechanical damage

Required thickness

Roll width and order quantity

Fire-performance requirements

Required test standards

Cladding or jacketing method

The complete aerogel felt product range can include different thicknesses, densities and temperature grades. Final selection should be based on the project conditions rather than on the lowest room-temperature conductivity value alone.

Frequently Asked Questions

What is a good thermal conductivity value for aerogel felt?

Many industrial aerogel felt products have a thermal conductivity of approximately 0.012–0.020 W/(m·K) at or near room temperature. The actual value depends on the product grade and test conditions.

Does aerogel felt conductivity increase at high temperatures?

Yes. Effective thermal conductivity generally increases with temperature. Buyers should request values at several mean temperatures covering the intended operating range.

Is thicker aerogel felt always better?

A thicker layer provides greater thermal resistance when the material and operating conditions remain the same. However, the optimal thickness should be determined through thermal calculations, installation limitations and project cost.

Can aerogel felt get wet?

Hydrophobic aerogel felt resists liquid-water penetration, but seams, damaged cladding and unsealed penetrations may still allow moisture into the insulation system. Proper weather protection remains necessary.

Can two layers of aerogel felt be installed?

Yes. Multiple layers are commonly used to achieve the required thickness. Joints should be staggered to reduce direct heat paths and improve overall insulation continuity.

Is the lowest conductivity product always the best choice?

Not necessarily. Buyers should also evaluate temperature range, mechanical strength, hydrophobic performance, fire classification, dimensional tolerances and installation requirements.

Conclusion

Aerogel felt offers very low thermal conductivity and can deliver high insulation performance with less thickness than many conventional materials. However, room-temperature conductivity alone is not enough to select the correct product.

Buyers should compare conductivity values at the project's actual mean temperature, confirm the test method and consider installed thickness, moisture exposure, compression and joint design.

By providing complete operating conditions and requesting reliable technical data, buyers can select an aerogel felt that achieves the required balance of thermal efficiency, installation thickness, durability and project cost.