Uw-value tests on VELUX, 
FAKRO, Roto and Keylite products

The results of Uw-value tests on our own and competitors’ products, made by the global consultancy Navigant at two different European notified test institutes during 2016-2018, found discrepancies between the declared Uw-values and the tested products’ Uw-values. We brought these findings to the attention of our competitors as well as to the relevant market surveillance authorities in July 2018.

The VELUX Group presented solid documentation to authorities and continued the testing of our own and competitors’ products in end of 2018. The new test in 2018 showed same discrepancies between the declared Uw-values and the tested products’ Uw-values as before. This means that we now have tested between 10 and 25 samples for each individual product variant. It seems that the test results indicate that the tested products brought to market by our three competitors, FAKRO, Roto and Keylite, to a large extent, do not comply with their declared Uw-values.

We believe this is an industry matter and that transparency about the state of Uw-values is paramount to creating a level playing field in the roof window industry. We want a fair roof window marketplace with a good reputation, so that consumers can rely on the qualities of the roof windows they buy as holding true. Therefore, we have made the results of tests by independent notified testing institutes ift Rosenheim, Germany, and Centrum Stavebního Inženýrství a.s., Czech Republic available below. Furthermore, we will continue testing products in the coming years.

The tests were carried out in accordance with the European standard (EN ISO 12567-2) for testing Uw-values of roof windows, using the reference roof window size. The roof windows were installed in the test boxes in compliance with the respective manufacturers’ guidelines. Therefore, we believe that the test results reflect the actual value.

Please click on Facts about the tests for more detailed information.

Contact us for more information on the tests >

  • Tested FAKRO products

    Tests at:
    ift Rosenheim, DE

    Product: 
    FAKRO
    PTP-V U3

    Uncertainty of measurement is from 
    +- 0,07 to +- 0,09 W/m2K depending on test
    Tested values graph

    Tests at: 
    Centrum Stavebního
    Inženýrství a.s. (CSI), CZ

    Product: 
    FAKRO 
    PTP-V U3

    Uncertainty of measurement is +- 3%
    Tested values graph

    Tests at:
    ift Rosenheim, DE

    Product: 
    FAKRO
    FTP-V U3 

    Uncertainty of measurement is from 
    +- 0,07 to +- 0,09 W/m2K depending on test
    Tested values graph
    In July 2018, FAKRO redeclared the Uw-value of FTP-V U3 from 1,2 W/m2K to 1,3 W/m2K after being notified about the test results.

    Tests at:
    Centrum Stavebního
    Inženýrství a.s. (CSI), CZ

    Product: 
    FAKRO
    FTP-V U3 

    Uncertainty of measurement is +- 3%
    In July 2018, FAKRO redeclared the Uw-value of FTP-V U3 from 1,2 W/m2K to 1,3 W/m2K after being notified about the test results.

    Tests at:
    ift Rosenheim, DE

    Product: 
    FAKRO 
    FTS-V U2 

    Uncertainty of measurement is from 
    +- 0,07 to +- 0,09 W/m2K depending on test
    Tested values graph

    Tests at:
    Centrum Stavebního 
    Inženýrství a.s. (CSI), CZ

    Product: 
    FAKRO 
    FTS-V U2 

    Uncertainty of measurement is +- 3%
    Tested values graph
  • Tested Roto products

    Tests at:
    ift Rosenheim, DE

    Product: 
    Roto 
    Q-4 K2C AL P5

    Uncertainty of measurement is from 
    +- 0,07 to +- 0,09 W/m2K depending on test

    Tests at:
    Centrum Stavebního 
    Inženýrství a.s. (CSI), CZ

    Product: 
    Roto 
    Q-4 K2C AL P5

    Uncertainty of measurement is +- 3%
    Tested values graph

    Tests at:
    ift Rosenheim, DE

    Product: 
    Roto 
    WDF R88C K WD AL

    Uncertainty of measurement is from 
    +- 0,06 to +- 0,08 W/m2K depending on test
    Tested values graph

    Tests at:
    Centrum Stavebního 
    Inženýrství a.s. (CSI), CZ

    Product: 
    Roto 
    WDF R88C K WD AL

    Uncertainty of measurement is +- 3%
    Tested values graph

    Tests at:
    ift Rosenheim, DE

    Product: 
    Roto 
    WDF R78 K WD AL 

    Uncertainty of measurement is from 
    +- 0,07 to +- 0,10 W/m2K depending on test

    Tests at:
    Centrum Stavebního 
    Inženýrství a.s. (CSI), CZ

    Product: 
    Roto 
    WDF R78 K WD AL

    Uncertainty of measurement is +- 3%
    Tested values graph

    Tests at:
    ift Rosenheim, DE

    Product: 
    Roto 
    Q-4 K2S AL P5

    Uncertainty of measurement is from 
    +- 0,06 to +- 0,07 W/m2K depending on test
    Tested values graph

    Tests at:
    Centrum Stavebního 
    Inženýrství a.s. (CSI), CZ

    Product: 
    Roto 
    Q-4 K2S AL P5

    Uncertainty of measurement is +- 3%
    Tested values graph

    Tests at:
    ift Rosenheim, DE

    Product: 
    Roto 
    WDF R85 K WD AL

    Uncertainty of measurement is from 
    +- 0,06 to +- 0,07 W/m2K depending on test

    Tests at:
    Centrum Stavebního 
    Inženýrství a.s. (CSI), CZ

    Product: 
    Roto 
    WDF R85 K WD AL

    Uncertainty of measurement is +- 3%

    Tests at:
    ift Rosenheim, DE

    Product: 
    Roto 
    WDF R75 K WD AL

    Uncertainty of measurement is from 
    +- 0,07 to +- 0,08 W/m2K depending on test
    Tested values graph

    Tests at:
    Centrum Stavebního 
    Inženýrství a.s. (CSI), CZ

    Product: 
    Roto 
    WDF R75 K WD AL

    Uncertainty of measurement is +- 3%
    Tested values graph
  • Tested Keylite products

    Tests at:
    ift Rosenheim, DE

    Product: 
    Keylite 
    CP-T 

    Uncertainty of measurement is from 
    +- 0,07 to +- 0,09 W/m2K depending on test

    Tests at:
    Centrum Stavebního 
    Inženýrství a.s. (CSI), CZ

    Product: 
    Keylite 
    CP-T 

    Uncertainty of measurement is +- 3%
  • Tested VELUX products

    Tests at:
    ift Rosenheim, DE

    Product: 
    VELUX 
    GGU 0070

    Uncertainty of measurement is from 
    +- 0,06 to +- 0,09 W/m2K depending on test

    Tests at:
    ift Rosenheim, DE

    Product: 
    VELUX 
    GGU 0070

    Uncertainty of measurement is
    +- 0,07 W/m2K
    Windows 1, 2 and 3 were not sourced through a dealer but sampled from a VELUX warehouse.

    Tests at:
    Centrum Stavebního 
    Inženýrství a.s. (CSI), CZ

    Product: 
    VELUX 
    GGU 0070

    Uncertainty of measurement is +- 3%

    Tests at:
    Centrum Stavebního 
    Inženýrství a.s. (CSI), CZ

    Product: 
    VELUX 
    GGU 0070

    Uncertainty of measurement is +- 3%
    Windows 1, 2 and 3 were not sourced through a dealer but sampled from a VELUX warehouse.

    Tests at:
    ift Rosenheim, DE

    Product: 
    VELUX 
    GLU 0051

    Uncertainty of measurement is from 
    +- 0,07 to +- 0,08 W/m2K depending on test

    Tests at:
    Centrum Stavebního 
    Inženýrství a.s. (CSI), CZ

    Product: 
    VELUX 
    GLU 0051

    Uncertainty of measurement is +- 3%