Thermal Resistance (R) is a measure of resistance to heat flow through a given thickness of material (related directly to the R-value). Thermal resistance is determined by taking the thickness of a sample and dividing it by its thermal conductivity. Thermal resistivity is the inverse of the thermal conductivity. Thermal resistivity and R-value are sometimes used interchangeably, however, thermal resistivity differs in that it is a material property (i.e. independent of thickness).
Thermal resistance is specifically used to compare the performance of insulation products. Insulation can take the form of foams, aerogels, or other thermal barrier materials. R-value is often used to quantify single layered samples but can also be applied to layered structures such as those in vacuum insulation panels.
A range of both transient and steady state methods are available for testing at TAL. The Heat Flow Meter (HFM) is considered the gold standard method for determining the thermal resistance of insulation. HFM allows us to measure the thermal conductivity from -10 to 60 °C, and we offer services with multi-temperature point measurements, within ASTM C518-17 specifications (see general HFM design schematic below). The Modified Transient Plane Source (MTPS) is well-suited for a wide range of materials. Specifically, the high-temperature MTPS configuration is ideal for testing insulations used in elevated temperature applications. Learn more about our equipment for thermal conductivity and thermal resistance testing here.
We offer MTPS and HFM testing for the thermal resistance of insulation, foams and other materials. Below is a selection of the measurement requirements for thermal resistance testing services.
| Measurement range | 0.002 – 1.0 W/mK |
| Sample size | 100 x 100 mm or 300 x 300 mm. Min. thickness of 5 mm. |
| Temperature range | -10 – 60 °C |
| Material types | Foams, aerogels, polymers and vacuum insulation panels |
| ASTM/ISO/EN Standards | ISO 8301, ASTM C518, EN 1946-3, EN 12664, EN 12667, EN 12939 |
Other methods may be available. Contact us at info@thermalanalysislabs.com or call (506) 457-0498 to discuss.
Thermal conductivity testing measures a material’s ability to conduct heat (how quickly heat passes through it), while thermal resistance testing measures how well a material resists heat flow. Essentially, conductivity reflects heat transfer efficiency, and resistance reflects thermal insulation performance.
The cost of thermal resistance testing depends on factors such as the sample type, testing method, and temperature range, and typically ranges from US$350 to US$500 per sample. Please contact us to request a personalized quote based on your specific samples and requirements.
You may submit a single sample or multiple samples, or request a quote, by contacting us through our online form, email, or call us at +1 (506) 457-1515. Please provide details about your material, sample count, sample sizes, and desired testing parameters to ensure an accurate quote.
Our thermal resistance testing can be performed across a wide temperature range, typically from room temperature up to 70°C (HFM), depending on the material and test method. Please contact us for specific requirements.
The heat flow meter measurement error arises from several individual factors, summarized in the table below:
| Error Type | Value (%) |
| Heat loss across specimen ends | 0.5 |
| Temperature difference measurement | 0.4 |
| Specimen thickness measurement | 0.5 |
| Inadequate thermal contact | 0.5 |
| Test specimen calibration uncertainty | 1.0 |
| Calibration non-linearity | 1.0 |
| Calibration uncertainty | 1.0 |
The HFM can measure a 20 mm thick specimen with an accuracy of approximately ±0.5 %, which corresponds to a possible deviation of ±0.1 mm. This level of precision requires the specimen surface to be flat and even.
We can measure a wide range of materials, including ceramics, polymers, composites, foams, and coatings such as paints. If you have a specific material, we can confirm its suitability for testing.
Typical turnaround time is 2 to 3 business weeks, depending on sample type, testing method, and workload. Expedited testing may be available upon request.
Sample requirements vary by material and testing method, but typically we need flat, uniform samples with sufficient thickness for accurate measurement. Surface preparation may include polishing to ensure proper thermal contact. Specific guidelines are provided when you submit your samples.
We provide clients with a comprehensive report that includes measured thermal resistance values, testing conditions, sample details, and relevant graphs or tables. Data can also be provided in digital formats upon request.
We follow internationally recognized standards for thermal resistance testing, including ISO 8301, ASTM C518, EN 1946‑3, EN 12664, EN 12667, and EN 12939. This ensures that our results are reliable, consistent, and comparable across different materials.