What is retrofit double glazing?

What is retrofit double glazing?

Warm, light-filled comfortable living

What is retrofit?

  • Retrofitting is the process of upgrading your single glazing to new double glazing.

  • Choosing to retrofit can help you save on your renovation budget. Instead of completely replacing your window which can be expensive, we replace your existing single glazed glass with a new factory sealed energy efficient double glazed unit, making retrofit a more affordable choice.

  • Our process involves making minor adjustments to the frame (such as a new aluminium or timber bead) to account for the new double glazed unit. The aesthetics look virtually the same allowing you to retain the character of your home.

  • Our double glazed units are factory sealed and then installed onsite. We do not use your existing glass. The process is relatively quick and hassle-free, leaving you to enjoy the comforts of your new double glazing.

  • You can combine our high performance Low E technology with your double glazing for the ultimate energy efficient solution. This means there is less need for heating and cooling appliances, helping you reduce energy consumption and power bills.

    • For example, with our advanced Low E technology you can get up to 79%* better heat retention compared to single glazing, keeping your home warmer and drier in winter.

    • If you live in areas prone to overheating in the hot summer months we have solar control glass options that can reduce up to 74%* of the sun's heat, helping keep your home cooler in summer.

  • Other lower-cost alternatives may be confused with Retrofit double glazing. Retrofit double glazing is a permanent replacement for single glazing, not a “clip-on” addition. It is a factory-sealed double glazed unit (as would be used in a new builds), fitted into your existing frames. Unlike a clip-on solution, our double glazed units are purpose-built and able to be tailored for each individual homes needs.

*compared to single glazing

The diagram below shows an example of a before and after retrofit double glazed window in an aluminium frame.

Diagram of heat loss prevention from double glazed windows

What is double glazing?

  • Double glazing is commonly used in windows and doors and is made up of two panes of glass separated by a spacer. The space between the glass is typically filled with air or an inert gas like argon.

  • Double glazing is an insulated glass unit (IGU) assembled and sealed in a controlled factory environment.

  • What does this mean for my home?  Choosing retrofit double glazing can provide better thermal insulation keeping your home warmer in winter and cooler in summer, allowing you to have a more consistent and comfortable temperature year-round.

  • Our double glazed units are locally processed in our New Zealand plants and distributed nationwide.

  • Our Retrofit double glazed units are regularly tested by BRANZ and are compliant with EN1279.

  • We will also ensure everything we quote is compliant with the New Zealand Standards for Glazing in Buildings, including the safety requirements for human impact & safety from falling.

  • All of our Retrofit double glazed units come with a 10-year warranty.

The diagram below shows an example of what a double glazed unit looks like:

Detailed illustration of Metro Low E Double Glazed Unit

What is Low E?

  • What Low E means: It is short for "Low Emissivity" glass.

  • Energy efficient: Low E glass is aimed to improve energy efficiency, with a special coating that lets in natural light while reflecting heat (increasing the insulation) and/or reducing unwanted solar heat gain to maintain indoor comfort levels.

  • Reduce power bills: Our Low E can reduce heat loss by up to 79% (compared to single glazing) which can help save you money on your heating/power bills

  • Helps reduce risk of overheating: If overheating is an issue for your home in the hot summer months, choose from our three solar control glass options - SunX™ Reflect Low E, SunX™ Grey Low E or Xtreme™ Low E. They all help reduce solar heat by up to 74% compared to single glazing and the Low E technology also keeps your home warmer in the colder winter months. Our two SunX™ products are our highest solar control glass, both have a tinted exterior appearance - great for homes in hot and sunny locations and rooms that experience glare.

  • Lets in natural light: Visible Light Transmission also called "VLT" is a measure that tells you how much natural light is entering through the glass. Each of our Low E double glazing options lets in different levels of light from Xcel™ Low E that lets in 80% of visible light, to Xtreme™ Low E that lets in 74% - both perfect for creating naturally light-filled spaces within your home.

  • Crafted for New Zealand conditions: Our range of Low E glass is tailored to New Zealand conditions, offering a variety of performance benefits to cater to your specific priorities

  • Tailored solutions: Based on your home and specific needs we can customise a retrofit double glazing solution incorporating the right Low E glass to provide you with the ultimate performance upgrade.

View benefits of Low E

The diagram below shows an example of how Low E technology works with your double glazing.

Diagram of Low E double glazing

What are the benefits of retrofit double glazing?

  • Our solutions are purpose built for each home. Most Kiwis retrofit their homes for a warmer, drier, more comfortable living environment.

  • Retrofit double glazing, especially when Low E glass is selected, has many benefits such as

    • Thermal insulation - keeping your home warmer and drier

    • Reducing the likelihood of condensation inside your home

    • Solar control - keeping your home cooler in summer

    • Consistent year-round temperatures

    • Fading reduction

    • Maintaining natural light levels and glare reduction

    • Reduce noise

To read up more on the benefits of Low E check them out below:

View benefits

What window frame do I have?

We can retrofit (double glazing  as a replacement for single glazing) into most aluminium and timber window frames. Click which frame type you have at home to view the process of how we retrofit aluminium and timber windows:

Aluminium Timber


If you have experienced the benefits of standard double glazing but want better performance or to change the aesthetics of your windows, we can provide an option to “reglaze”. We can upgrade your standard/classic double glazing to a high performance Low E double glazing option, giving you the ultimate performance upgrade.

Reglaze

What are my retrofit double glazing solutions?

We have a range of double glazing options to suit your priorities. Each solution is customised and tailored to each home. View our range by clicking below

View range
condensed windows in aluminium windows

Up to 50% of heat is lost through your windows and doors

Choosing the right Low E glass can make a real difference to your comfort, keeping you warm in winter, cooler in summer and reducing your power bills.

*MBIE Consultation Document Building Code 2023

Couple talking in home, while looking at double glazed windows online

Is retrofitting right for my home?

We understand that each home is different, our expert Retrofit consultant will assess your home, and recommend a tailored solution for you and your budget.

Get a free quote

CHRISTMAS & NEW YEAR HOLIDAY CLOSURE: All Retrofit branches will be closed from 12pm Friday 20th December, returning Monday 13th January. Have a safe & happy holidays!
SUMMER PROMOTION - Get a FREE UPGRADE on your Retrofit Double Glazing quote. Use promo code: FREEUPGRADE25. Request your free quote here. Terms apply.