We keep the warmth inside

Highly energy-efficient center pivot windows FTT


FTT U8 Thermo* with coefficient Uw=0.58W/m2K (equivalent R-Value 9.8)
FTT U6 – with coefficient Uw=0.8W/m2K (equivalent R-Value 7.1)

* test result for the whole roof window (FTT U8 Thermo) with EHV-AT Thermo flashing testing compliant with EN ISO 12567-2, equivalent R-Value 9.8


Please note, standard glazing units are only suitable for installation of up to 3,000 feet above sea level.

Highly energy efficient windows


  • Exceptional roof windows intended for energy-efficient and passive construction.
  • The glazing unit is set in a particularly designed sash frame. It has wider wooden profiles, compared with a standard window. This design reduces the occurrence of thermal bridges and delivers better insulation of the window. FTT Thermo U8 window with a heat transfer coefficient of Uw = 0.58 W/m2K (equivalent R-Value 9.8) is the warmest roof window on the market with single glazing unit. Supplied and installed complete with flashing EHV-AT Thermo. As standard, it is also equipped with a set of insulation flashings XDK containing an insulation set XDP and air-tight flashing XDS.Windows opened via pivot with hinges located above the window mid-height, thanks to which even the tallest person in your family can comfortably stand upright by the open window. Special window structure utilizing wider sash frames and quadruple sealing system.
  • Easy cleaning the external glass and fastening awning blind thanks to a special bolt which blocks the sash when rotated up to 180°.
  • Increased burglary-resistance – topSafe system.


Uw parameters for roof window

Assembled together with E HV-AT Thermo flashings


topSafe system

Topsafe® system of burglary protection as standard


FTT U8 Thermo - window of the future

The FTT window with innovative structure ensures excellent thermal insulation performance and large energy savings.
The FTT U8 Thermo window featuring Uw = 0.58 W/m2K (equivalent R-Value 9.8) is the most energy-efficient roof window with a single glazing unit available on the market. It significantly exceeds the energyefficiency requirements for roof windows which will become effective from 2021. The FTT U8 Thermo complies with passive construction requirements, which is confirmed by Passive House certificate.

Application of comprehensive solution ensures fulfilling energy-efficient
function of the window and allows to reduce heat loss as well as bills for heating the building.

See the structure and advantages - FTT U8 THERMO





  • FTT U6

    • Glazing unit U6highly energy efficient glazing unit U6
    • Suitable for pitches from 15-70suitable for roof pitches 15 to 70 degrees
    FTT U6 Thermo
    • 0,14 BTU/hft²F (0.8 W/m²K) window U-value 0,09 BTU/hft²F (0.5 W/m²K) glazing U-value 38 dB acoustic insulation Rw 7.1 window R-value 6HT-18-4H-18-33.2T glazing unit argon inert gas filled panes + external glass toughened + internal glass laminated, anti-burglary glass class P2A twice varnishing five seals Elegant handle
  • FTT U8 Thermo

    • Glazing unit U8passive U8 glazing unit
    • Flashing EHV-AT Thermothe most efficient roof window available on the market. Supplied and installed with flashing EHV-AT Thermo
    • Suitable for pitches from 15-70suitable for roof pitches 15 to 70 degrees
    • Flashing XDPinsulation flashings XDK consisting of insulation set XDP and air-tight flashing XDS
    FTT U8 Thermo
    • 0,10 BTU/hft²F (0.58 W/m²K) window U-value 0,05 BTU/hft²F (0.3 W/m²K) glazing U-value 36dB acoustic insulation Rw 9.8 window R-value 4H-12-4HT-12-4HT-12-4HT glazing unit krypton inert gas filled panes + external glass toughened twice varnishing five seals Elegant handle

FTT Thermo available sizes

Size EU [cm]
Size US [in]


55 x 98
22 x 39

78 x 118
31 x 47

78 x 140
31 x 56

Outside frame



547 x 981

21½ x 38⅝

777 x 1181

30½ x 46½

777 x 1401

30½ x 55⅛

Rough opening



577 x 1011

22½ x 39½

777 x 1211

31½ x 47½

777 x 1431

31½ x 56¼