What is uPVC and Is it a Sustainable Construction Material for Doors and Windows?

One of the most pressing concerns of the Australian construction industry right now is improving the sustainability of materials, in a cost effective way.

A material that’s been sparking conversation is unplasticised polyvinyl chloride, uPVC. With a longer life cycle than traditional materials thanks to its strength and durability, many architects, builders, and even homeowners are asking – is uPVC truly sustainable and how can it be used?

We recently broke down the benefits of uPVC on our podcast ThermoTalk. Let’s look at what it is, where it is used, plus how it improves the overall sustainability score of a property.

What Exactly Is PVC?

Understanding uPVC first requires an understanding of ‘Plasticised’ PVC. Polyvinyl chloride is widely used in the construction industry as it has excellent weather resistance, electrical insulation, and surface properties. It is self-extinguishing, flexible and often used in wire covering.

The chloride in polyvinyl chloride is 57% salt. However, it is also 43% ethylene, a by-product of oil. That means buildings constructed with PVC depend heavily on the oil industry.

As a fossil fuel, oil is composed mainly of hydrocarbons. Its extraction, transportation and combustion contribute hugely to emissions of carbon dioxide, the most dangerous of the greenhouse gases. The changes caused to the earth’s atmospheric layer by greenhouse gases are a significant cause of climate change.

So, the future of sustainable construction depends on finding affordable alternatives to petroleum, or innovative ways of recycling old products.

How Does uPVC Differ from PVC?

The clue is in the ‘u’. uPVC stands for unplasticised polyvinyl chloride, a rigid, hard, and highly durable version of flexible PVC. Its exceptional strength makes it a popular choice for window and door applications.

Unlike standard PVC, uPVC doesn’t require chemical plasticisers to enhance its toughness. Instead, it relies on strong impact modifiers and fillers, creating a high-quality material that also requires low maintenance. This durability makes it perfect for window frames, door frames, and even pipes and gutters — structures that must withstand Australia’s harsh weather conditions year after year.

How Is uPVC Made and Why Is It So Strong?

As uPVC’s surface hardness is equal to aluminium, it’s a popular material for construction.

Its strength lies in the molecular structure of the plastic itself, plus how it mixes with other ingredients that make up the finished product.

uPVC has long spaghetti-like strands called polymers. These strands twist around each other during manufacture to strengthen the versatile material. Other ingredients, called impact modifiers, are added that bind the strands together. This means that anything made from uPVC – such as window and door frames – has extra resistance to bumps and knocks.

The impact modifiers bond more to the polymer strands and strengthen the plastic. With consistency, uPVC is up to 6% stronger when it’s recycled the first time. The next four or five times it’s recycled, it will still get stronger but by a smaller amount each time.

How Much Stronger Are Recycled uPVC Frames?

Often people don’t realise that ‘recycled’ doesn’t mean inferior to new. Recycled uPVC products can in fact be better and stronger.

Double glazed windows and doors made from uPVC can last up to 35 years before they’re replaced. So, if the material used is recycled, they could be getting stronger and stronger for over 300 years.

Using Life Cycle Analysis (LCA) to Determine Sustainability

Life Cycle Analysis (LCA) is a meaningful way to measure the footprint on the planet from human activity and is used by scientists to determine the sustainability of a material.

LCA quantifies the inputs and outputs of a product, process or activity. It also compares a material’s environmental impact and the availability of alternatives. This includes a ‘cradle-to-grave’ or ‘cradle-to-cradle’ assessment of product systems. No single material takes the trophy of being 100% sustainable from cradle to cradle.

How Does LCA Measure the Sustainability of Building Materials?

Nowadays, LCA is a tool to compare building designs. At first, LCA focused on environmental effects. This included risk of acid rains, or harmful chemicals run-off from the land into our lakes. But nowadays it also assesses greenhouse gas emissions and the carbon footprint.

The materials used in window frames are so important when it comes to sustainability.

Considering the life cycle and embodied energy of windows is key.

Window performance relates to embodied energy over the product’s life cycle. Its thermal efficiency and structural performance are also significant.

Embodied energy is the total amount of energy consumed for the construction of a window or door. The total energy required to mine, harvest, manufacture, transport and install a window.

LCA first assesses the durability of the material, as it’s important that windows aren’t sent to landfill every ten years. Then, there is a calculation and comparison of U values and thermal performance. Carbon footprint is the last step in the analysis. All this determines the total sustainability of window materials.

So, is uPVC a sustainable material according to its LCA? On the balance sheet, it has a much better carbon footprint than aluminium and a greater thermal performance than timber.

How Can We Improve the Sustainability Score of uPVC?

It’s possible to continue improving the sustainability score of uPVC with closed-loop recycling. This means not using new energy to produce new windows and making recycling existing ones into new windows the focus. This will improve the construction industry’s overall sustainability.

In effect, reaching a critical mass of uPVC will have a highly positive impact on the environment. The more recycled uPVC there is in circulation, the less the construction industry needs to rely on oil as raw material. Simultaneously, less plastic will go into landfill or incineration.

Thermotek uPVC Windows and Doors Offer Superior Performance and Energy Efficiency

Thermotek windows and doors are engineered in Germany and manufactured locally in Australia, designed for outstanding thermal performance and energy efficiency. With a focus on heat insulation, statics, and sealing, they create an airtight barrier against air, wind, and rain. Their innovative locking mechanism and high-quality sealing ensure durability and reduced maintenance.

The uPVC used in Thermotek products has high thermal insulation properties, while the insulated glass units (IGUs) feature standard low-E glazing with argon gas. The streamlined 60mm profile is fully insulated with a dual-seal frame, offering versatility across a wide range of building designs.

Thermotek’s 3-chamber uPVC profiles provide an affordable alternative to thermally broken aluminium, helping architects and builders install high-performance windows and doors without exceeding project budgets.

Leading the Market in Sustainable Doors and Windows

Thermotek is committed to sustainable, low-waste manufacturing. All products are 100% recyclable, lead-free, and made from a calcium-organic chemical compound. The company partners with Aluplast and the global VINYL 2010 initiative to reduce resource consumption and increase the use of recycled materials.

Beyond materials, sustainability is embedded in Thermotek’s initiatives. The Thermotree of Life program plants a tree for every order placed, with clients receiving a certificate for their personalised Thermotree.

Looking for more insights into smart, sustainable living? Tune into ThermoTalk, the Thermotek podcast, available on SoundCloud.And if you’re planning a build, talk to us today about how our innovative window and door systems can help improve your building’s overall sustainability score.