Tx Thermal Effusivity Touch Tester

Quantify the Warm-Feel / Cool-Touch Sensation of Textiles and Fabrics according to ASTM D7984


Textile selection based on perceived warm-feel. Low effusivity means it feels warm.

C-Therm’s touch tester is the only product for quantifying touch performance that fully complies with ASTM D7984. The Tx Touch Tester is employed by the top global sports apparel brands and textile testing labs including Adidas, Columbia Sportswear, Marks (Canadian Tire), Intertek, the Taiwan Textile Research Institute, and Bureau Veritas.

Touch is a critical performance attribute in material selection and quality control for bedding textiles, automotive, and fabrics apparel sectors. Thermal effusivity quantifies how materials feel to the touch, whether warm or cool, taking away the guesswork for industries that want to improve product performance.

This testing was traditionally performed using panels of people, who could subjectively verify whether one material felt warmer or cooler than another, as the thermoreceptors in the human hand can detect the difference between materials. However, such human touch testing is extremely subjective to people doing the touch testing, and having an instrument that can accurately measure thermal effusivity takes away this variability for testing a wide range of materials for different use cases and applications.

Materials with a low thermal effusivity feel warmer and materials with a higher thermal effusivity feel cooler. Testing materials for their thermal performance and touch properties has a broad range of applications, including activewear, diapers, denim, and personal protective clothing, to name a few.

Thermal effusivity testing for textiles has been standardized by the American Society for Testing Materials (ASTM). The industry led standard, ASTM D7984, utilizes C-Therm’s patented Modified Transient Plane Source (MTPS) technology for measurement. C-Therm’s MTPS sensor, employed by the TX Effusivity Touch Tester, is the only standardized instrument for characterizing the thermal touch properties of textiles and other materials.

How Consumer Brands Use “Cool-Touch” and “Warm-Feel”

What thermal effusivity measurement is required to support claims that a material can warm you up or cool you down?

Major brands are noted to be currently employing a minimum threshold of greater than 185 Ws1/2/m2K as the minimum effusivity value for classifying a material as “Cool-Touch”. Conversely, a range of somewhere between 65 – 100 Ws1/2/m2K is typically seen in classifying materials that rank in the “warm-feel” category. That said, it is important to recognize that the desired effusivity value in selecting a material is often contextual to the apparel product category and may vary considerably. Individual brands set their own performance standards for their products based on a variety of performance considerations. The importance of the effusivity value of the material needs to be considered as part of a broader evaluation of the overall material performance, including performance attributes that impact comfort such as wicking, breathability, etc.


Tx Effusivity Touch Tester: Simplify Thermal Effusivity Testing with the Modified Transient Plane Source (MTPS) Technique

Measure the thermal effusivity of textiles with the Tx Effusivity Touch Tester by C-Therm, creators of industry-leading thermal conductivity equipment who helped develop the ASTM D7984 standard. The Tx Effusivity Touch Tester is the only instrument that conforms to the standard.

This thermal effusivity instrument is equipped with the patented Modified Transient Plane Source (MTPS) sensor, a single-sided sensor that measures the thermal effusivity of a broad range of textiles and fabrics in 1 to 3 seconds. Industry leaders rely on the MTPS sensor to test product performance including Mark’s, Under Armour, adidas, Columbia, Tempur Sealy, and 3M.

To learn more about the Tx Effusivity Touch Tester, request pricing from C-Therm and we will provide more information for measuring thermal effusivity for your application needs.

Request Custom Pricing

academic research icon Tx Touch Tester is part of C-Therm’s Academic Support Program. Check all the benefits and eligibility criteria here.

C-Therm’s Trident Instrument with Tx Effusivity Touch Tester Configuration and the Compression Test Accessory

Tx Effusivity Touch Tester Product Specifications

ASTM D7984 sensor textile test CTA

Compression Test Accessory with single layer Air Hoop ASTM D7984 sensor

Thermal Effusively Range 5 to 1,600 Ws½/m²K
Additional Measurements Thermal conductivity
Specific heat capacity (derived)
Temperature Range -50º to 200ºC
Moisture Range 0% – 90% Relative Humidity (non-condensing)
Precision Better than 1%
Accuracy Better than 5%
Test Time 0.8 to 3 seconds
Sensor Size 18mm diameter
Minimum Sample Size Min. diameter of 18 mm
Min. thickness is dependent
on the thermal effusively.
Maximum Sample Size Unlimited
International Standard ASTM D7984
Test Method Modified Transient Plane Source (MTPS)

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C-Therm products with the Quick Ship icon are in inventory and typically available for shipment within 4-6 business days. Times vary depending on final configuration. Does not include some accessories and third-party items such as thermal chamber or lab furnace. Request a quote to confirm shipping availability.


  • Bureau Veritas Guangzhou

    We offer ASTM D7984 testing with the TCi in our lab. We were impressed with the service and support provided by C-Therm."

    Martin Ho,
    Manager - Softline Testing

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  • adidas

    The device is working perfectly."

    Dr. Christian Heyde,
    Sport Science Manager

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Book a Tx Effusivity Touch Test Demo

Measuring touch properties is important for the textile industry where thermal effusivity measurements factor into marketing claim validation, R&D, and quality control. When you schedule a virtual demonstration with C-Therm, we will guide you through using the Tx Effusivity Touch Tester for your application.


Methods for Measuring Thermal Effusivity: The Q-Max Method vs The MTPS Method

Before thermal effusivity instruments were developed, researchers relied on The Q-Max method to test the warm- or cool-touch of fabrics and other materials. The Q-Max value does not measure thermal effusivity directly—it uses heat flux to get an approximate measurement of thermal effusivity.

Repeatability and accuracy are common issues with this method as results can vary between instruments and laboratories. Additionally, manual placement of the hot sensor onto the material is a common issue as it can be difficult to establish consistent contact during the measurement process. Despite these issues, the Q-Max method provides a broad range of environmental operating conditions (humidity, pressure) that can closely mimic real-world applications.

The MTPS method measures thermal effusivity directly using a single-sided sensor. A sample is placed onto the sensor and a heat pulse is applied only after consistent contact is established, which leads to better repeatability of results.

Recent research conducted by C-Therm and the Shanghai Entry-Exit Inspection and Quarantine Bureau demonstrated a correlation between measuring materials using the Q-Max value and measuring thermal effusivity directly with the MTPS method. Comparing 16 samples, researchers found similar results between the two methods.

The advantages of using the MTPS method to measure thermal effusivity include:

The Tx Effusivity Touch Tester has become the global standard for measuring the “warm-feel” or “cool-touch” of textiles and other materials. Powered by C-Therm’s patented Modified Transient Plane Source (MTPS) sensor, it is the only instrument that is recognized by ASTM International for measuring thermal effusivity.

How the Tx Effusivity Touch Tester Works

The Tx Effusivity Touch Tester employs the Modified Transient Plane Source (MTPS) technique. The one-sided, interfacial heat reflectance sensor applies a momentary constant heat source to the sample. Thermal effusivity is measured directly, providing a detailed overview of the thermal characteristics of the sample.

  • Unifi Manufacturing Inc.

    For any group interested in measuring the thermal effusivity of materials, I would absolutely recommend C-Therm to them. The machine can be set up to analyze many different types of materials, which makes it a very versatile tool."

    Katherine Barrows,
    GIT Prototype & Technology Manager

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Watch the Webinar: Using the MTPS Method to Quantify Temperature Regulation (Q-Max Correlation)

Quantifying the warm-feel and cool-touch of fabrics plays a significant role in temperature regulation for performance textiles. Watch the webinar to learn about methods for measuring heat flux, including a comparison of the MTPS and Q-Max methods.


What are the Units of Thermal Effusivity?

Thermal effusivity calculates what it feels like when your hand comes into contact with a material; the sensation of warmth or coolness as you encounter an object at ambient room temperature.

Thermal effusivity units are Ws1/2/m2K and is a measurement of the square root of three values:

  • Thermal conductivity (W/mK, or watts per meter-kelvin)
  • Density (kg/m3, or kilogram per cubic metre)
  • Heat capacity (J/kgK or Joule Per Kilogram Per Kelvin)

To learn more about the correlation of effusivity and touch perception and calculating warm-feel/cool-touch thermal properties, watch C-Therm’s webinar on quantifying thermal touch performance.

Watch the Webinar

Applications for Thermal Effusivity in the Textiles Industry

C-Therm’s TX Effusivity Touch Tester allows researchers to quantify the thermal touch properties of textiles in order to find the materials best suited to an application, support performance claims, conduct quality control, and more.

To learn more about thermal effusivity, including how people feel it, how thermal effusivity is quantified using instruments, and how it factors into product, marketing, and research and development decisions, watch the video below.

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Textile selection with different thermal effusitivy.

Video transcript: Touch. It’s one of our critical senses in perceiving the world—everything from the clothes we wear to the bedding we sleep in. The thermoreceptors in our skin monitor and relay information to our brains about everything we come in contact with. This helps us make decisions about what feels pleasant to the touch and keeps us safe. Human skin is very good at detecting differences in a material’s ability to transfer heat, such as the warmth of a fleece sweater compared to the coolness of leather.

This material property is known as thermal effusivity—as a metric, it can be used to quantify a textile’s ability to exchange thermal energy between skin and fabric. Why is this important? Because human test panels have established a positive correlation between our touch perception of the warmth or coolness of a textile, and its thermal effusivity. In other words, our perception that certain materials will keep us warm or help us cool down is quantifiable. We know this is important in quantifying performance in a wide range of applications—including diapers, activewear, personal protective clothing, upholstery, neoprene dive suits, and bedding. Our skin’s thermoreceptors are giving us good information, though subjective.

The C-Therm Tx Effusivity Touch Tester quantifies warm and cool feel for you, making what was previously subjective into a metric that can be quantitatively measured. It provides accurate measurements across a range of real world scenarios, including higher humidity environments and under varying compressive loads. The C-Therm Tx Effusivity Touch Tester measures the science of touch—so you can provide the comfort.

C-Therm Thermal Effusivity Instruments Are Trusted Globally By Leading Textile Testing Facilities

In 2016, C-Therm worked with industry to form a new ASTM standard for characterizing the touch properties of textiles and fabrics based on C-Therm’s MTPS technique. Today, various brand companies and testing labs around the globe have adopted C-Therm’s Tx Effusivity Touch Tester into their R&D and quality control processes.

Below is a quick guide to laboratories worldwide that offer ASTM D7984 testing:

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Case Studies for Thermal Effusivity Measurement

C-Therm adapted the MTPS sensor to characterize the thermal properties of a range of textiles and fabrics. Learn more about the different applications of thermal effusivity below.

Characterizing The “Warm-Feel” Of Activewear Textiles

Manufacturers of high-performance apparel use thermal effusivity measurements to evaluate whether a material is able to keep you cool during high-energy activities, or keep you warm in colder environments. A fabric with a higher thermal effusivity feels cool, while a fabric with lower thermal effusivity feels warm. Using C-Therm’s MTPS sensor, a major Canadian retailer is able to measure the “warm-feel” of textiles in order to create thermal underwear and activewear. The table below highlights results from four candidate materials in terms of their thermal effusivity.

Characterizing The “Cool-Touch” Of Bedding Textiles

Producers of bedding textiles aim for materials with a high thermal effusivity because they can promote that their products have a “cool-touch.” Using the TX Effusivity Touch Tester, a mattress supplier tests three different coatings to determine which one has a higher thermal effusivity. The chart below highlights results from the study.

Measuring Thermal Effusivity Under Wetted Conditions

An outdoor retailer was interested in assessing how the feelings of “warmth” changed with increased moisture content. Water has a very high thermal effusivity (~1600 Ws½/m²K) compared with that of dry textiles (100 – 200 Ws½/m²K). Notice the thermal effusivity of the cotton textile is twice the effusivity of the micro-fibre material when moderately wet with 10 sprays of water. Incidentally, when fully saturated, both materials have an effusivity very close to that of water itself. This reinforces that if you fall in a cold lake, the best thing you can do to improve your comfort is to remove your clothing upon exiting. However, technical apparels such as this micro-fibre material can provide substantial improvements in comfort under moderate wetting conditions.

Testing the Performance and Comfort of Diapers

Nothing feels better on a baby’s skin than a dry, warm diaper! Diapers are made of 3 key layers: the topsheet, the surge layer, and the absorbent core. When wetted, the diaper’s surge layer disperses the liquid throughout the absorbent core, reducing the wetness from the topsheet and the overall coldness of the diaper. Thermal effusivity can quantify the diaper’s ability to exchange thermal energy between the diaper and the baby’s skin. In characterizing the thermal effusivity of the diaper under dry and wetted conditions, the performance of the diaper can be quantified as to a critical performance attribute for the product based on touch or feel. High effusivity values represent a “cool-feel” and low effusivity values indicate a “warm-feel” to the material. Water has an effusivity value of ~ 1600 W s1/2 m-2 K-1, compared to a dry diaper in the range of 50-100 W s1/2 m-2 K-1.

Test Results

Comfort and warmth are associated with a low thermal effusivity. Therefore, diaper companies strive to achieve the lowest possible thermal effusivity value when their diapers are dry and wetted. As seen in the chart below, the thermal effusivity increases dramatically after the diaper is wetted. However, the leading brand diaper can maintain a more comfortable feel for the baby after the diaper is wetted.

Thermal Effusivity of no name brand diapers vs leading brand diapers

Measuring Material Quality Under Compaction

When testing some fabrics, it may be necessary to measure thermal effusivity as the material is being compressed. This can be accomplished using C-Therm’s Compression Test Accessory. There is no standard level of compression available, as the level of compression is dependent on the application. Compression force is intended to measure performance under “real-world” conditions. For example, the level of compression you would use to test the insulation quality of a down jacket would be minimal compared to measuring a down sleeping bag.

Case Highlights

Analyzing the thermal insulation properties of knitted fabrics

knitted fabric 1

Generic weft knitted fabric

In 2020, C-Therm’s Thermal Conductivity Analyzer (TCi) was used to measure the thermal properties of knitted fabrics as part of a study from the Alexander Dubcek University in Trencin, Slovakia. One of the purposes of this study was to evaluate the thermo-physiological comfort of this type of fabric, so thermal conductivity and thermal effusivity were two key factors to take into account. Other characteristics were analyzed, however, here we will be focusing on these two.

Ten different samples were analyzed during the study, and they are detailed in Table 1.

Table 1. Material composition and basic parameters of weft knitted fabrics. [1]

textile highlight tci 1

C-Therm’s TCi system offers fast and accurate measurement of the thermal conductivity of material using the simplest and most versatile transient method, MTPS (Modified Transient Plane Source). This method is easy to use and employs a single-sided sensor to directly measure thermal conductivity and effusivity of materials with high precision, high sensitivity, short test time. Learn more about TCi’s principles of operation here.

tci test setup knitted fabric

TCi test setup [1]

Table 2 indicates average values of the thermal property measurements acquired during the study.

Table 2. The results of thermal insulation properties on device C-Therm TCi. [1]

textile highlight tci 2

According to the study, “the high thermal resistance values were measured for plush weft knitted fabric which had different material compositions (samples 8, 9, 10). The best results were achieved by a plush weft knitted fabric which had a higher content of polyester (sample 9). […] the high value of the thermal resistance is also reached in an interlock knitted fabric (sample 7) due to the greater thickness and form of knitted structure. Even though layer knitted fabrics (samples 1, 2) contain 30% of wool component + membrane + 65 % polyester, they have lower thermal resistance values than plush weft knitted fabric. These are very negative results for relatively expensive materials. It is due to their lower thickness and other use (on the second layer of clothing) compared to others. Samples 3, 4, 5, 6 also have a lower heat insulation capacity due to lower thickness. Their different material properties did not lead to significant changes in thermal resistance. However, for a given assortment, the thermal resistance value is sufficient. […] The highest value of thermal effusivity was measured for samples 3, 4 and the lowest for samples 5, 8, 10. Then samples 3, 4 appear as cold for touch and samples 5, 8, 10 as warmer for touch. […] increasing the thickness and drop in specific density leads to the increase in the thermal resistance of the weft knitted fabrics [6]. In that case, weft knitted fabrics which have a greater thickness and smaller specific density will be appropriate thermal insulators.” [1]


[1] J Legerská et al. Evaluation of thermal insulation properties and dynamic moisture transfer of knitted fabrics, 2020 IOP Conf. Ser.: Mater. Sci. Eng. 776 012100

Effusivity of Automotive Interior Overhead Panels

car interior panel

Generic Automotive Interior Overhead Panels

C-Therm offers effective and accurate analysis for a wide variety of applications that are key in the manufacturing context. An analysis of automotive interiors, particularly for overhead panels, was done using C-Therm’s instrument. Manufacturers strive to combine layers of materials to form the final panel packages that are insulating to heat and sound, meeting the satisfaction of customers while remaining cost-effective.

A series of seven extracted samples of automotive interior overhead panels were tested. Each sample was tested three times on the front face (the side exposed to the car’s interior) and three times on the back face (the side exposed to the car’s roof). A 500g weight was placed on top of the sample to ensure good surface contact at the sensor’s interface.

The results are presented in the table below, showing excellent precision and separation between interior overhead panel packages from various automobile manufacturers.


Audi 5000 (front) 108.3 0.5 0.5 Layers: fabric, fibreboard, cardboard
(back) 169.8 2.0 1.2
Nissan Stanza (front) 104.6 0.6 0.6 Layers: fabric, compressible foam, polymer, foam core, polymer
(back) 160.4 0.5 0.3
Buick Regal (front) 96.7 0.5 0.6 Layers: fabric, compressible foam, polymer, foam core, compressible foam
(back) 112.1 0.7 0.6
Oldsmobile Delta 88 (front) 95.1 0.5 0.5 Layers: fabric, compressible foam, fiberglass mesh, layered fiber insulation, fiberglass mesh
(back) 106.6 0.2 0.2
Hyundai Stellar (front) 135.9 0.4 0.3 Layers: woven fabric, foam core, fiberboard
(back) 241.1 2.0 0.8
Ford Taurus (front) 98.3 0.3 0.3 Layers: fabric, compressible foam, fiber insulation
(back) 118.6 0.2 0.1

SD: standard deviation; RSD: relative standard deviation in the physical property reported (± %)

Ready to Get Started with Thermal Effusivity Measurement? Get Pricing

Organizations seeking thermal effusivity measurements need to determine how to adapt instruments for their application. When you request pricing from C-Therm, you’ll also receive a customized recommendation for how to measure thermal properties for your application and industry.

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The Tx Touch Tester is part of C-Therm’s Academic Support Program. Check all the benefits and eligibility criteria here.



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