What is Optoglas®

Optoglas is a trademarked system for manageable and easy energy optimisation and sound insulation of existing windows.

Optoglas is a heat-treated piece of glass, fitted on the inside of the original window frame to create a coupled window. This makes it easy to open the window without worrying about objects on the windowsill and without preventing inflow of light.

Optoglas can be fitted on side-hung, top-hung and fixed frames as well as on inward-opening, outward-opening and fixed frames.

Optoglas was designed, invented and patented by architect Ulrich Schirning and is an invisible, aesthetic solution for energy optimisation of old or newly manufactured single-glazed windows, primarily in old or listed buildings. However, Optoglas can also be fitted on new, double-glazed windows to optimise energy use and reduce noise levels.

Sustainability, comfort and indoor climate
Optoglas is a sustainable solution, and due to the fact that it is fitted on existing window frames it helps improve comfort and indoor climate with a minimum of inconvenience. As panes are made to measure, it is also suitable for oblique or curved frames.

Guarantee
As a member of the Danish Association of Glaziers, we offer our customers the security of a five-year guarantee on all accessories.

Glass is not merely glass
Heat-treated glass is ordinary glass heated to 650°C and then rapidly cooled down. This makes the glass almost five times stronger than ordinary glass. The heat treatment also affects the shear pattern of the glass. When heat-treated glass is subjected to a heavy impact it breaks but shatters into small fragments, reducing the risk of serious cuts. Heat-treated glass is also highly heat resistant and able to withstand temperatures of up to 275°C. In very rare cases and under certain circumstances, tension in the glass may cause it to rupture.

Lets in light
Heat-treated glass does not affect external light or colours more than ordinary glass. Ordinary glass is slightly green, which is the colour that steals least light and gives least colour distortion – the colour rendering index is high.
Heat-treated glass can be combined with various types of functional glass such as coloured glass, UV protective glass or energy glass.

Better indoor climate with energy glass
Energy glass is ordinary, heat-treated glass with a selective low-emission coating on one side. The coating is extremely thin and transparent, causing the glass to reflect heat radiation back into the room. At the same time, it lets in solar energy and visible light. When the room heat is reflected back, thermal insulation improves considerably and the inner glass gets warmer. The high surface temperature reduces or even eliminates cold down-draughts and cold radiation from the window surface, which helps improve the indoor climate. In terms of light inflow, the properties of energy glass are almost identical to those of ordinary glass.
From the left: Energy glass, standard glass.

Energy glass is ordinary, heat-treated glass with a selective low-emission coating on one side. The coating is extremely thin and transparent, causing the glass to reflect heat radiation back into the room. At the same time, it lets in solar energy and visible light.

When the room heat is reflected back, thermal insulation improves considerably and the inner glass gets warmer. The high surface temperature reduces or even eliminates cold down-draughts and radiation from the window surface, which helps improve the indoor climate. In terms of light inflow, the properties of energy glass are almost identical to those of ordinary glass.

In connection with energy labelling, the Department of Civil Engineering at the Technical University of Denmark (DTU) performed heat transmission and energy calculations for pine windows fitted with Optoglas. According to DTU Civil Engineering, the total U-value of frame, casing and pane is 1.7 W/m2K for a pinewood window with a 4 mm single pane in the outside frame and an Optoglas 4 mm heat-treated energy glass pane fitted on the inside. The total U-value of frame, casing and pane is 1.39 W/m2K for an equivalent window with double-glazing on the outside.

External noise can be inconvenient in homes and workplaces. There are many different ways of reducing noise levels. Depending on the type of noise – and, of course, the extent of the noise – Optoglas could be a solution.
An acoustic test performed by Delta (specialist in acoustic measurements) indicates a significant reduction in traffic noise when Optoglas is fitted.

In the case of single-glazed windows, fitting Optoglas reduces noise by 31 dB.

This increases to 40 dB when Optoglas is fitted on double-glazed windows.

A reduction of 10 dB halves the noise level.

On 1 January 2017, after over 20 years at Optoglas ApS, Frede Nielsen decided to hand over the business to his son, Thomas Nordahl, and his daughter-in-law, Janne Axelsen. Thomas is a qualified carpenter and has developed and restored both new and old properties for many years. Janne has a Bachelors degree in architecture and a Masters degree in communication.

We have chosen to continue the business because we feel that Optoglas is an attractive product with great benefits for buildings and consumers alike.

Why choose Optoglas?

  • Energy optimization

    Optoglas insulates 30% better than similar thermal windows and has a better U-value (2.2) than a 2-layer thermal pane. By using special neutral energy glass, a U-value of 1.7 is achieved – equivalent to a 3-layer thermal pane (DS 418).

  • Instructions and installation

    We have extensive experience in restoration craftsmanship and offer both guidance and installation of Optoglas on your existing windows.

  • Better indoor climate

    Optoglass improves the indoor climate while reducing outside noise, making your property more comfortable.

  • 5-year warranty on all fittings

    As a member of the Glaziers’ Guild, you get a 5-year warranty on all fittings installed in connection with Optoglas on your current windows.

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