PVC stands for polyvinyl chloride, which is a family of plastics used extensively in the building, and other, industries since the 1950’s. uPVC stands for unplasticised PVC and has characteristics making it very suitable as a window frame material. First produced commercially in the late 1920s, PVC has become one of the most widely used polymers in the world and represents a highly efficient conversion of raw materials. Due to its versatility, PVC is used across a broad range of industrial, technical and everyday applications from window profiles and pipes to credit cards, water bottles and blood bags. Our website and other material refers to both PVC and uPVC synonymously.

Yes. The first commercially available windows were installed in Germany in 1959. While the technology for producing these windows has naturally advanced over the years with, for example, the introduction of better performing acrylic-based impact modifiers, some of these earlier uPVC windows are actually still in use. Additionally, over 60% of European homes now have uPVC windows and doors.

Yes. Viewed across its life cycle, PVC is highly competitive in terms of its environmental impact. Several recent eco-efficiency and Life Cycle Assessment (LCA) studies on the most common applications show that, in terms of energy requirements and GWP (Global Warming Potential), PVC is at least equal to alternative products. In many cases, it shows advantages both in terms of total energy consumption and lower CO2 emissions.

The core materials for PVC production – chlorine and ethylene – are both by-products of other manufacturing processes. Chlorine is a by-product of caustic soda production with source raw materials of seawater and rock salt. Ethylene is a by-product of the petroleum refining industry i.e. PVC is not directly dependent on crude oil.

No, it’s not a good idea for a number of reasons!

• Climatic suitability – the PVC profiles imported by us are of a formula optimised for the very high levels of UV radiation New Zealand has and of a profile design optimised for South Island winter temperatures. Any PVC imported – especially cheaper PVC – on a DIY basis is very unlikely to be well suited to South Island climatic conditions.
• Approvals – windows need to be approved by governing bodies in New Zealand. The approval process is expensive i.e. 10’s of thousands of dollars and time consuming and of course there is no guarantee they will actually be approved. Installing unapproved windows is illegal.
• Additionally, some DIY importers have come unstuck when importing glass that does not meet NZ safety standards. What can start out as a money-saving exercise can easily become very expensive!
• Support – importing critical products that are not supported locally comes with significant risk.

Emissivity is the term used to describe the ability to radiate absorbed energy.

The sun radiates ultraviolet (UV) light, visible light and infrared (IR) light. Ultraviolet light causes interior materials such as fabrics, floorings and wall coverings to fade. Visible light is the light humans can see – and also contributes to fading, whilst infrared light is heat energy. While infrared light does not contribute directly to fading, the heat caused by the absorption of IR radiation can influence the fading process.

Low E coatings have been developed to minimize the amount of ultraviolet and infrared light that can pass through glass without compromising the amount of visible light that is transmitted. Low E glass has a microscopically thin, transparent coating – it is much thinner than a human hair – that reflects infrared energy (heat) and ultraviolet light. When the interior heat energy tries to escape to the colder outside during the winter, the Low E coating reflects the heat back to the inside, reducing the radiant heat loss through the glass. The reverse happens during the summertime.

Maximum thermal performance is achieved by combing both argon and Low E. Compared to a double-glazed unit without argon and Low-E, the combination of the 2 boosts thermal performance by more than double. R-value improves from 0.37 to 0.85.

Argon is the gas used between panes in a double- or triple-glazed window. The inert gas is naturally occurring, colourless, odorless and harmless. Argon is denser than the atmosphere, providing more thermal efficiency than having air between the panes. Additionally, the presence of argon ensures a more even temperature distribution within the glazing unit, further reducing the chance of condensation.

Maximum thermal performance is achieved by combing both argon and Low E. Compared to a double-glazed unit without argon and Low-E, the combination of the 2 boosts thermal performance by more than double. R-value improves from 0.37 to 0.85.

There are several reasons:

1. Thermal performance – aluminium is highly heat conductive so they are not well suited to temperate climates and houses fitted with them require additional energy consumption for heating and cooling and often suffer condensation problems.
2. Health – condensation breeds mould and with mould come dangerous spores. Such environments have been proven to be associated with respiratory illnesses: nose and throat symptoms, cough, wheeze, and asthma symptoms. There is also evidence that these environments can be associated with shortness of breath, the development of asthma in people who did not previously suffer from it, and lower respiratory symptoms (coughing, wheezing, chest tightness, and shortness of breath).
3. Environmental friendliness – aluminium is produced from the non-renewable ore, bauxite. Aluminium production requires a great deal of energy (225MJ/kg) and it generates huge amounts of environmentally dangerous pollutants like carbon dioxide, acidic sulphur dioxide, along with polyaromatic hydrocarbons (PAHs) fluorine and dust. Although New Zealand does produce aluminium, all raw materials are imported: bauxite/alumina from Australia, crude oil from Alaska USA, and coal from China and Korea – again adding to the environmental impact of aluminium windows.

Environmental friendliness – most people believe using wood is the most environmentally friendly option for window frames because of the “natural is better than synthetic” assumption. But if wooden frames are to maintain their technical and thermal properties they require regular treatment using very environmentally unfriendly chemicals.

Interestingly, DEFRA (Department for Environment Food & Rural Affairs – UK government) commissioned a study on the life cycle analyses of PVC and timber in window profiles. In analysing the various impacts across the lifecycle, it was found that there are only marginal differences in the environmental performance between the two. Although trees are not a scarce resource, the facts around de-forestation, particularly the logging of ancient or old-growth forests warrant further understanding. The logging of these forests can lead to a decrease in biodiversity, as habitats are destroyed in the logging process. Tree plantations are grown, in their place, for the intense farming of timber and wood products. This itself can lead to soil erosion and nutrient degradation, vulnerability to pest attack, reduction in water supply, over use of fertilisers and social impacts.

Additionally, caution needs to be taken in accepting claims of an increase in forested areas. Scandinavia presents an interesting example relating to the misconceptions surrounding so-called ‘sustainable forestry’. Eco watchdog, Friends of the Earth comment: “More trees are not a good thing when they are replacing valuable wildlife habitats. Scandinavia has now just 5% of its original old-growth forest remaining, yet this is still being logged. Also almost 50% of Finland’s peat bogs have been drained, mostly for planting managed forests.”

Additionally, like most things, not all wooden windows are the same. There are both very good quality and poor quality wooden windows available in NZ. Poor quality wooden windows will likely result in warping and delamination.