Innovation provider

Viking Window AS


72751 Estonia
Tel: +3723848900


Thermal windows with standard window thermal transmittance Uw = 0.88 W/m²K. Thermal windows are manufactured of special wooden profiles with the additional thermal insulation. The insulation material is added to the profiles while lamination process before profiles are finished in window factory. Thus ensuring the strength and integrity of the window frames.
Thermal windows may be used in passive houses and other low energy buildings.


Profile system used for thermal windows is based on tilt and turn window IV78 profiles which enables to achieve better thermal performance with same hardware system. That gives an additional benefit for the company - there is no need to change machine settings while changing from regular production to high energy efficient windows.

Thermal window has 6.4% better insulation than the regular 3-glazed tilt and turn window of IV78 system (Uw = 0.88 W/m²K instead of Uw = 0.94 W/m²K). In Estonian climate it can provide energy saving approximately 6.7 kWh/m² year compared to regular 3-glazed windows. Considering that in Estonia today the most common new window has Uw = 1.4 W/m²K the energy saving rate is approximately 58.7 kWh/m² year (37% lower energy demand).

Additional benefit with thermal windows for consumer is based on internal wall temperatures. In case of -10°C external temperature, the internal window surface remains 16…17°C if room temperature is 20°C. Thermal windows ensure thermal comfort and help to avoid condensation problems.

Innovative aspects (ecologic, social and economic)

Thermal window technology improves energy efficiency of buildings which means it helps to save energy.
By using thermal windows in buildings it is possible to achieve better living conditions through improved thermal comfort.
Labour input to thermal windows production is the same as with regular windows. Materials (profiles and glazing) are with higher cost. As a result manufacturing thermal windows is more profitable than manufacturing regular windows.

Application examples

Thermal windows are meant to be used in external walls of buildings.


Thermal windows need additional investment when bought; maintenance is no different from regular windows.


Current stage of development

Already on the market
Exported to other countries 

Export to Finaland, Sweden, Denmark

Intellectual Property Rights

Secret know-how

Country of origin


Country of application

Denmark, Sweden, Finland



National Contact Point

Antti Roose
Tartu Ülikooli, Geograafia Osakond
Vanemuise 46
51014 Tartu

Tel: +372 737 6841
Fax: +372 7375825