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Retrofit Double Glazing vs uPVC joinery with Double Glazing

If you have decided to double glaze your windows, you might be wondering what options you have to change your single glass to a better performing product.

You can either retrofit your old aluminium or timber windows and doors with a new double glazed glass, which is a relatively quick and small project. The other option is to change your complete framing to uPVC joinery. Even though it will cost you more, it will also offer further benefits, such as exceptional thermal performance and soundproofing.

Eco Auckland highlights some of the pros and cons of each method to help you select the best option for your needs and provide you with a comfortable home.


Retrofitting new double glazed units into your existing timber or aluminium joinery




Retrofitting will give you the cheapest double glazing option on the market. If you have a lower budget or would like to save some money on the renovation, then retrofitting your old timber or aluminium joinery with better performing glass will be the most cost-effective option for you.


Because retrofitting does not require a significant amount of labour and specific manufacturing, it usually has a much faster lead time and quicker installation than any other double glazing option.


Some of us love the original characters of our homes and want to keep the exact look of the exterior of the house. In this case, retrofitting your windows with double glazing will ensure you retain all the timber or aluminium joinery that make your property special. All the framing, such as sills, facings and reveals, remain the same, and you will be able to keep the design you are so attached to.


If you don’t want your home to be exposed to the New Zealand environment for a long time, retrofitting gives you the option to get double glazed windows without having to open any walls.


timber and aluminium issues

Deciding to go with retrofitting means that you retain all the issues that can come with timber and aluminium joinery. You will need to paint your timber sills regularly and check to see if they don’t rot or warp. Your aluminium windows will still condensate and let cold air in.

not sealing properly

Old joinery and framings mean that your windows and doors will likely not seal as well as they could. This will lead to a lower thermal performance of the double glazing than what you might expect. Retrofitting is challenging to do without any leaks.

high maintenance

Timber joinery is extremely high maintenance, having to be painted every few months to retain a nice look. You will need to periodically check for any rotting or warping to ensure they still offer the comfort you are looking for.

What to be mindful of

If you choose this method because of the benefits it offers, make sure your double glazed glass has at least a 10mm gap between the panes. If the gap is any smaller your new windows won’t give you a much better thermal performance than your single glazed ones would. This gap can be challenging to achieve on thinner aluminium frames.

uPVC joinery with double glazing


Thermally efficient

If you want to have the warmest possible home, uPVC joinery with double glazing would be the best option for you. It is the most thermally efficient option on the market and works well in even the harshest New Zealand environments, including at places with strong winds, snow and rain. They seal 100% so that they won’t let in any gusts or cold air at all.

Low maintenance

This option is extremely low maintenance. Unlike timber windows that need painting and rot relatively quickly, uPVC frames can simply be cleaned with warm soapy water every few months. To ensure that the hinges and handles work well, they should be lubricated every four to six months. You will never have to spend too much time maintaining your windows and doors!

Large double glazed options

If you are looking for large windows and doors, uPVC options will be a great choice for you. They come in many different sizes and functions. All our uPVC double glazed windows come with a 24mm total thickness, which allows for a 16mm air gap between the two panes and ensures your home is fully protected against environmental factors.

Modern look

All uPVC joinery has a modern and innovative look, which will give the exterior of your home a renewed look. We can even manufacture the frames with different colours so that they will look good with your home’s current design. uPVC windows will add a significant value to your property and offer you more benefits than just double-glazed glass.

Retain your home’s character

On the other hand, if you want to retain the original character of your home, we can also make that happen with the uPVC frames. With the different coloured options, we will ensure your new frames look the same as your aluminium or timber ones if that’s what you want.


More expensive

uPVC joinery with double glazing is a more expensive process than retrofitting your old window and door frames. So, if you don’t want to spend a significant amount of money

Changing both the glass and the joinery of your windows and doors can be relatively expensive, especially if you are looking for large surfaces. If you don’t want to spend a significant amount on the renovation process, retrofitting may be a better option for you.

Longer lead time and installation

Changing both the joinery and glass in your windows and doors will also take a much longer time. Custom making your windows for your home will take a long lead time, especially if you want special functions and large-sized surfaces. If you wish to enjoy the double glazing benefits quickly, then retrofitting could work out better for you.

More invasive

Replacing the windows, doors and joinery in your home is a relatively invasive process and will leave your home exposed to environmental factors for a longer time. You might not be able to install in cold, rainy weather.


If you want the most thermally efficient option on the market for your windows and doors, then uPVC joinery with double glazing is an excellent option. You will not only get a warm home but will enjoy the added benefits of a quiet, secure and eco-friendly place. Eco Auckland has a wide range of uPVC joinery available for your needs. Contact us today to discuss your options with the team and start your journey towards a comfortable home!