Stärke uses glass that is compliant with NZS 4223 in all window & door units. Therefore you can trust us to ensure your glass is meets the safety requirements so that your family or colleagues are safe.

Glass also plays a big role in the comfort of your home. When optimised, double glazing acts as an insulator as the air space reduces noise, and the transfer of heat or cold from inside to the outside & vice versa. Other types of glass such as Low E glass can further improve the thermal efficiency.

In Winter when it is cold outside, less warmth escapes through the glazing units and, in summer, it can reduce the heat gain and U.V rays from outside and ease the load on your cooling system or Air- conditioning. By combining different glass types and thicknesses we can help you choose a high performance option that suits your individual needs.

Single & DOUBLE glazing

Single glazing is a single piece of glass, therefore does little to reduce transfer of heat, light, sound or U.V Fading. Single glazing is less commonly used, unless for an internal window or door or in an area that doesn't require extra insulation such as a garage.

Double glazing or an insulated glazing unit is made of two layers of glass with a sealed air space between. Double glazing is a requirement in new homes and will help to reduce sound, heat and light transfer, U.V fading and condensation. Check out our glass selector for more comparisions.



Obscure glass is used for privacy as it restricts the visibility through a window. It is commonly used in areas like bathrooms.
There are a few of types of obscure glass available; Stippolite & Etchlite are the most popular however it all comes down to what type you prefer. See below for images of obscure glass types.



Low E glass has a coating which improves its thermal efficiency. The coating is virtually invisible, but will have a positive impact on the heat transfer through the glass.

Low E glass is available in a range of performance levels, what type you choose will depend on your home and requirements.


Tinted GLASS

Tinted glass can be used to reduce the glare and fading from the sun or as an aesthetic feature.

Grey tinted glass is most common in New Zealand homes, however green, blue and bronze tinted glass is also available. See below for images of tinted glass types.



Choosing the right glass for your windows & doors can be challenging with the many types of glass available. The main factors to think about when choosing your glass are heat, fading, sound and light.

By choosing the right glass for your windows, you can dramatically increase the energy efficiency and comfort of your home.

All Stärke windows & doors comply with the NZ Building code NZS4223.


With compact housing and traffic or industrial noise, sound reduction is an important factor when choosing glass.
There are a range of glass types that will reduce sound, but it does depend on the frequency and pitch of the sound as to what type of glass is most effective.



U.V / Fading

U.V damage or fading to furnishing to something that is often thought about when selecting glass. You can reduce fading by selecting glass that reduces the U.V transmission through the window.

Tinted glass is an effective option for reducing fading as the interlayer absorbs the UV light. To further reduce fading we suggest to combine tinted glass with laminated glass. Reflective glass is the best to reduce fading, but it is not commonly used in homes.



Heat Gain

Heat gain from the sun is a common challenge in New Zealand homes. Double glazing can help maintain inside temperatures by reducing the heat transfer from outside.

Tinted glass and Low E will further reduce the heat gain as they absorb solar energy. Reflective glass is the best option to reduce solar heat gain, but it is not commonly used in homes.



Heat Loss & Condensation

A standard double glazed unit will effectively reduce your heat loss and condensation in comparison to a single glazed window. To further enhance the insulation, we recommend you combine double glazing with Low E and Argon Gas as the best solution with up to 70% heat loss reduction compared to 4mm clear single glazing by keeping the inner pane of glass warmer. Thermal Spaces can further enhance performance and help reduce condensation. Note: Double Glazing doesn't eliminate condensation.



Light & Glare

The glare from the sun can be frustrating in areas exposed to the sun. Glare can be minimised by choosing glass that reduces the light transmission.

Low E coating helps to reduce light transmission, tinted glass will further reduce the glare. Reflective glass is the best to reduce light and glare, but it is not commonly used in homes.



Safety & Security

Your safety is important and the NZ building code stipulates that certain sizes or locations must be able to withstand impact without breaking. Standard safety glass will shatter rather than break, however there are special glass types with varying penetration resistance through to bullet resistance glass. 
All Starke windows & doors comply with the NZ building code. For standard safety requirements, toughened or laminated glass is sufficient.