U-value measurement

In the field of building physics, U-Value is the term used to describe the heat transfer coefficient of a building element (e.g. of a wall). The U-Value describes the insulation quality of a building. The unit of the U-Value is W/(m²K). The smaller the U-Value, the better the insulation quality of the building element.

But how to measure the U-value? Our measurement-approach uses a Heat Flux Sensor and two temperature sensors (see image below). This approach is standardized in ISO 9869, ASTM C1046 and ASTM C1155. This is the only method which delivers reliable quantitative in-situ information about a building envelope.

Read about a U-Value measurement with our gSKIN® U-Value KIT in a case study from ETH Zurich.

To differentiate our measurement-approach from other often applied approaches we reviewed the most common ones:

1. Table Look-up (Building Catalogue)/ U-Value Calculation
   There are complex databases containing λ-Values of generic building elements ordered by element material and/or year of construction. With these databases, the U-value of a building envelope (e.g. wall) is calculated by adding all materials contained within the specific element (e.g. specific wall = 20cm concrete + 20cm glass wool). While this method is very simple and quick, it does not produce an accurate U-Value, only an approximation.
2. Thermography (i.e. Infrared imaging)
   This approach shows the thermal radiation of an object and produces an image showing spots with higher and lower radiation. It does not produce a U-Value, it just produces an image.
3. Multiple Temperature Measurement
   This approach is based on three or more temperature measurements on both inside and outside of a building element. While this approach produces a U-Value, it needs a minimum temperature difference of 10 °C between the inside and outside to work and it is assumend that the thermal boundary resistance is constant.

Key Features

Easy to mount

You can use normal adhesive tape to fix our sensor to any wall or window.

Easy to transport

The U-value Kit can easily be carried in our transportation box.

Real-time review

You can review measurement protocols easily on your laptop.

Short measurement

If you do not need to follow ISO guidelines, you can measure U-Values in less than an hour.

Easy analysis

A professional, easily understood software is provided

Many applications

The U-Value Kit / Sensors can be applied within R&D applications to e.g. improve insulation of materials, etc.

Applications

Typical application areas include measurement of building insulation, windows, and various industry driven R&D fields.

Thermal energy enters buildings mainly from the heating system and from solar irradiation. The energy exchange between the building and the outside is focused through the roof, walls, windows, and thermal bridges e.g. balconies, into the soil, and through exchange of ambient air. Every building is a complex thermal system and to optimize these systems (for example to reduce heating costs), precise data is required.

As the measurement set up for glass differs due its low thermal capacity to the influence of radiation for opaque materials. Our U-Value-Kit can also be easily installed to measure the U-Value of windows.

Understanding the thermal environment within R&D activities is often important.

While in many R&D applications temperature sensors are sufficient to establish an accurate understanding of the thermal environment, it is not always the case. When deeper insight into thermal processes is required, heat flux measurements provide the needed data. For example, heat flux is important to measure for the understanding and optimization of PCMs and other thermal storage materials.

How to measure the U-value? 6 Steps to get started

Choose an optimal measurement spot on the building element of interest.

On the inside of this spot, place the heat flux sensor, and one temperature sensor.

On the outside of this spot, place the second temperature sensor.

Connect all three sensors to the data logging unit.

Start the measurement process (via your Laptop).

Evaluate the U-value of the wall element with the software included .

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Downloads

gSKIN® U-Value Kit

Overview of the key features
Datasheet
Instruction manual

General Information

R-value vs. U-value
Comparison: Heat flux vs. temperature based method
Summary of ISO 9869

ISO compliant U-Value Measurement  (by ETH Zurich)
FAQ

Forgeign language articles

Chinese – U值测定 节能之道
French – Coefficient de transmission thermique
Japanese – “Ｕ値”評価 ＝ 数値として評価を得る
Korean – U-Value 측정 솔루션
Russian – Измерьте коэффициент теплопередачи, чтобы сэкономить 
Spanish – Determinación del Valor-U – L calidad-precio
Swedish – U-värdesmätning – valuta för pengarna!

Application Notes

Building physics
Minergie verification measurements (by ETH Zurich)
Wall
Window
Refrigerator
Occupied building
Quarrystone wall

News and Publications

• Future of building skins
• Zero-energy building
• U-value international
• Regional Experts
• Archive

The future of building skins: conference in Bern

greenTEG will exhibit at the 11th conference on the future of building skins in Bern, Switzerland (10.-11. October). The conference serves as a platform for architects, engineers, scientists, and the building industry with the aim of reducing the energy consumption of buildings. During the conference recent developments in the design of building skins as well as new products for increased energy efficiency of roofs and facades will be presented.

Send us an email if you attend the conference and would like to schedule a meeting with us.

Exhibition partner opens zero-energy multi-family home

Our exhibition partner, the environmental arena Spreitenbach, opened the first multi-family house in the world that operates without external connection to electricity, oil and natural gas.
Visit the Umwelt Arena in Spreitenbach and experience our U-value kit in a live demonstration. Read more about the energy-independent house and our U-value kit.

U-value articles in different languages

U-value related Articles in different languages are now available:

Chinese – U值测定 节能之道
French – Coefficient de transmission thermique
Japanese – “Ｕ値”評価 ＝ 数値として評価を得る
Korean – U-Value 측정 솔루션
Russian – Измерьте коэффициент теплопередачи – сэкономьте Ваши деньги
Spanish – Determinación del Valor-U – L calidad-precio
Swedish – U-värdesmätning – valuta för pengarna!

 

List of Energy Consultants in certain regions

You are searching for information about local Building Energy Experts? Find information here.

Germany KFW – List of Energy Consultants Federal Minsitry of Energy – List of Energy Efficiency Experts	beraterboerse.kfw.de energie-effizienz-experten.de
Switzerland Geak – List of Energy Experts	geak.ch
United States of America BPI Goldstar Contractor	bpihomeowner.org
United Arab Emirates Dubai – Green Building Consultants	ehss.ae

Archive

Video: How the measure the U-value?		Youtube
Article: Quality of building insulation precisely measured		ccr-mag.com
Article: The imprtance of U-values of windows		futurebuild.com
Article: U-Value assessment – getting value for money		Climate Control ME
Upcoming book: Reference to U-Value Kit		wiley.com
R-value vs. U-value		greenteg.com

List of Energy Consultants in certain regions

You are searching for information about local Building Energy Experts? Find information here.

Germany KFW – List of Energy Consultants Federal Minsitry of Energy – List of Energy Efficiency Experts	beraterboerse.kfw.de energie-effizienz-experten.de
Switzerland Geak – List of Energy Experts	geak.ch
United States of America BPI Goldstar Contractor	bpihomeowner.org
United Arab Emirates Dubai – Green Building Consultants	ehss.ae