Traditional Double Hung

High Performance Wood Windows

There are are three methods to restoring or replicating "historic" windows:


  • Onsite or offsite depot level restoration which maintains all the original details as well as leaving the wear and tear of time. This is suitable for building that still retain original windows and glass

  • Museum grade replication which duplicates in every detail and construction feature the original designed and built window. It is suitable for buildings where original components are missing

  • New windows that maintain the general look and operation of original windows. This method should be named “Traditional”, not “historic”. Other than sight lines, there is nothing “historic” about them other than a marketing gimmick.


Our traditional  wood window maintains the original look and feel of the classic double hung  with all the benefits of the latest energy performance. It is most suitable for new luxury construction or for adaptive reuse of historic buildings 

The Viking series double hung  sash window design,  ensures that windows have good weather performance. The meeting rail on the sashes are separated, thus avoiding wear on the weather strip . On closing the window the sashes are pulled against the weather strip, making for a tight window.

Windows are fitted with  Torso balance springs and with cam locks and handles on bottom the bottom rail. Both sashes have tilting possibility for easy cleaning of the sash.


Thermal transmittance Uw = 1,4 W/m2K.

The advantages of the sliding sash double hung wooden window:

  • Contemporary appearance and sleek design

  • Excellent storm proof detailing

  • Excellent thermal performance

  • Durability and ease of use

  • Robust Dimensions for strength and longevity -  Frame: 1 3/4 " x 5 5/8" Sash: 2 3/8" x 2 3/8"

  • All parts have been vacuum deep-impregnated with the GORI impregnation system

  • Maximum sash weight: 77 lb

  • Custom paint and stain options

  • Insulated glass unit: Double-glazed with low-E glass. Maximum U-value of the glass unit is 1.1 W/m2K.​

  • Custom paint and stain options

  • We can provide an FSC Chain of Custody certificate  which certifies that we use timber from responsibly managed forests

  • Our quality management system complies with the ISO 9001 standard

  • Our environmental management system complies with the ISO 14001 standard

The window can be combined with mullions, fixed light and fixed sash. Ogee mouldings are applied to the inside of the sash profiles. As decoration the top frame can be fitted with decorative horns on the outside. 

The long life of wood is guaranteed by the use of slow grown engineered Baltic Pine and the Teknos treatment system. Double glazed sealed units are used to maximize energy saving and noise reduction. Anti solar glass is available as an option.

The classic sliding sash hung window has been evolving for over 350 years:


  • The professional will immediately notice the clever and innovative improvements on the mechanics of the Viking series. The performance speaks for itself.

  • For the application to historic buildings being restored for adaptive reuse, there are thousands of exterior and interior moulding and trim possibilities. Think of it as a high performance automobile where the drivetrain and chassis remain the same with the exterior and interior custom fitted.

  • We include a vintage hand drawn section to spark the imagination!

  • We provide standard operating hardware, but most bespoke premium hardware lock and lift fittings can be applied to the Viking Window


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©2018 by IQ Radiant Glass Steel Windows

IQ Radiant Glass ®

Villanova, Pennsylvania,19085, USA

 610. 246.3922