Launched in 2010, Homestar is the independent system that rates the health, efficiency and sustainability of New Zealand homes on a scale of 1-10. It assesses energy, water, waste, ventilation, health and comfort, and other environmental factors, at Design and Built stage, and is certified by the New Zealand Green Building Council (NZGBC). NK Windows supplied the windows and doors for New Zealand’s first 10 Homestar rated built home. See more here.

Launched in Christchurch, the Superhome Movement is aiming to revolutionise the way Kiwis look at housing by helping people build warm, dry, healthy, energy-efficient and environmentally sound homes.

The Superhome Movement is gathering the very best in learning, products, and expertise to help you get a much better new house for your money. A specific goal is to help at least 1,000 new homeowners to build their Superhome in the next three years.

Vendor membership is by invitation only. NK Windows is proud to be a member and supporter of the Superhome Movement.

For a house to be considered a Superhome it must have a 6-10 Homestar rating. Modern houses built to only achieve NZ Building Code compliance will achieve a Homestar rating of 3-4. Houses built prior to October 2008 will typically achieve a Homestar rating of 2-3.

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. 

See more information here.

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

  1. Climatic suitability – the PVC profiles imported by NK Windows 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.
  2. 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.
  3. 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!
  4. Support – importing critical products that are not supported locally comes with significant risk.

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.

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.

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. See here for more information.
  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. See here for more information.

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.

See here for more information.

Yes. “PVC windows” refers only to the frame material. PVC window vendors have access to the exact same glass options as aluminium and wood window vendors.

Yes. NK Windows has been in business since 2000 and is here for the long haul. We partner with significant and market-leading suppliers from Germany, Austria and New Zealand.

PVC framing outperforms all variants of aluminium framing including thermally broken options. Unlike other window vendors, all glazing options from NK Windows come with a warm edge spacer to minimise thermal transfer between the panes of glass.

Aluplast Ideal 4000 PVC frame has an R-value of 0.77. 

A double-glazed unit (glass only) with argon and Low E has an R-value of 0.85. 

Aluplast Ideal 4000 PVC frame with argon and Low E double-glazed unit, has an R-value of 0.84. 

See more information here.

Many of the PVC window and door opening styles provide multipoint locking as standard. Depending on the size and opening style windows and doors will lock on 1, 2, 3 or 4 sides.

Regardless of size, all windows and doors from NK Windows have steel inserts for rigidity and strength. Frames are fastened through the PVC and steel to the building structure.

Glazing options include a full range of heat-treated and laminated safety glass providing the highest levels of protection possible.

Most of the PVC window and door opening styles are glazed internally i.e. glass is fitted from inside the house and cannot be removed from outside the house.

See more information here.

PVC provides natural noise absorbency performance advantages over aluminium and wood. This combined with precision German designed and manufactured twin mechanical rubber sealing within a continuous groove provides superior protection from unwanted noise. PVC frames are welded at the joints and have multi-chamber construction, again providing noise protection advantages over competing technologies.

See more information here and here.

Tilt and turn windows and doors were first developed in Germany in the 1940s and are now widely used throughout the UK and Europe. Although available in New Zealand for 20+ years, the T&T system is relatively unknown and is often met with surprise and intrigue.

T&T windows and doors provide dual functionality i.e. they allow the same sash unit to both tilt inwards and turn inwards – simply determined by the handle position.

T&T windows and doors provide multipoint locking on 2, 3 or 4 sides as standard depending on the size of the window or door. On most non-locking sides a hidden compression device is used to stop the frame flexing or lifting if someone attempts to pry it open. These features provide exceptional security benefits and peace of mind.

Internal glazing beads mean the glass can only be installed and removed from inside the house – it cannot be removed externally.

The tilt opening provides excellent ventilation security at street level and is impossible for a child to climb out of. A window can be locked in the tilt position if a locking handle is fitted. Restrictors can be fitted for child safety.

The tilt position allows daytime gentle air movement ventilation whilst maintaining high levels of security and safety with a 120mm opening. The tilt position can be safely used during periods of rain.

In the turn position, large amounts of ventilation can be achieved quickly.

A night venting option is available that provides a 10mm tilt opening.

The turn position allows easy access to the exterior frame and glass surfaces for safe cleaning. 

The PVC component of our windows and doors are corrosion resistant. However care must be taken, as with all metallic components around and in your house, to protect against corrosion of the opening and locking hardware. We offer specialist hardware, called Tricoat-Plus, designed for corrosive environments such as close to seawater, swimming pools or near water treatment plants. Product testing includes a 480-hour salt spray. A 15-year guarantee is provided for Tricoat-Plus hardware. 

See more information here.

Anything you want really. We partner with Viridian Glass based in Christchurch. By default we quote 2 glazing options:

  • Standard Double Glazing – no argon, no Low E
  • Planitherm XN Double Glazing – includes argon and high performance Low E

75% of all windows we sell are fitted with the high performance Planitherm XN Double Glazing option in a 4-16-4 configuration i.e. both panes of glass are 4mm thick with a 16mm gap between them. The 16mm gap is the largest available and contributes to the best thermal performance. A wide range of safety, security, privacy, coloured and thermal resistant glazing options are available. We also integrate leadlights into windows and doors.

The PVC profile is precision cut and welded, has steel inserted, opening and locking hardware fitted & tested and glazed in our Christchurch factory. Our glass is processed and cut to order in Christchurch by Viridian Glass.

As standard you will receive 3 keys per locking door cut. More can be ordered or copied at a later time if required.

No specialist skills or equipment are required to provide normal maintenance of the PVC and glass. Dishwashing detergent mixed with warm water, a cloth and a squeegee is all that is required for normal cleaning. Internal opening windows make cleaning easy and safe.

For all moving and locking window hardware, an acid-free lubricant such as petroleum jelly e.g. Vaseline should be used.

Light machine oil e.g. 3-IN-ONE, sewing machine oil or a light coloured, free pouring oil should be applied to all guide slots.

NK Windows have maintenance plans available.

See more information here.

The main window opening types are:

  • Fixed windows – they don’t open
  • Tilt & turn windows – option to tilt inwards (hinged at the bottom) and turn inwards (hinged vertically). Can be configured to tilt-only if required.
  • Awning windows – open outwards (hinged at the top)
  • Casement windows – open outwards (hinged vertically)
  • Sliding (including multi sliding) - slide left or right
  • Other opening types are available upon request such as: tilt & slide, folding, turn (inwards opening hinged vertically), and lift & slide.

See more information here.

The main door opening types are:

  • Entrance doors – inwards or outwards opening
  • Tilt & turn doors – tilt inwards (hinged at the bottom) and turn inwards (hinged vertically)
  • French doors – outward or inward opening. Main door can tilt if inward opening is selected
  • Tilt & slide – tilt inwards and slide
  • Fold & slide (bi-fold) – inwards or outwards opening
  • Multi slide (stacker)
  • Lift & slide

See more information here.

PVC profiles are available in white and creme as standard. Colouring options include factory-applied laminates - colour and texture - both sides or single-sided. Restrictions apply when opting for single-side laminates. We hold stock of white, creme, anthracite grey (exterior single-side on white) and golden oak (both sides). Other laminate colour options are ordered from the Aluplast factory in Germany.

There are a total of 45 colour options.

The use of coloured glass is popular in front doors.

See more information here.

It depends on the number of windows and doors to be installed and the complexity of the job including heights, hill sections, access, etc. Typically a house-lot installation will take two visits over 3 to 4 days. Our installation teams won’t leave your house insecure overnight though and will be fully compliant with H&S regulations.

PVC – 10 years

Glass – 10 years

Hardware – standard product 2 years / Tricoat-Plus corrosion resistant 15 years

PVC windows are still relatively unknown in New Zealand and are occasionally met with resistance from architects and builders. We suggest you insist. We will happily work with architects and builders to ensure a fantastic outcome for you. We have had clients fire their architect and builder because of such resistance!

Yes. The PVC profiles used by NK Windows are formulated for New Zealand climatic conditions including high UV levels. The same formula is used in other high UV areas such as the Middle East, Australia and Latin America.

NK Windows partner with German-based Aluplast GmbH for PVC profile systems. They are world-leaders in the field and focus solely on PVC for window and door systems. Their products are used around the globe. The raw materials used by Aluplast for window profiles are based on a calcium-zinc chemical stabiliser that is strictly lead-free. With this eco-friendly stabiliser and Aluplast’s involvement in “VINYL 2010”, that among other things dictates the use of recycled materials in their plastic profiles, Aluplast offers window systems that can be fabricated and recycled in an ecologically sound way. http://www.aluplast.net

It comes from proven European hardware manufacturers Maco Group (Austria) and Roto-Frank (Germany) and New Zealand based Windsor Brass. All 3 vendors produce exceptionally well designed and precision engineered hardware componentry to the world. We are proud to offer their stylish, innovative, highly reliable and secure products to you including 50+ handle and lock combinations.

R-value is a measure of thermal resistance used in the building and construction industry. Around most of the world, including New Zealand, R-values are given in International System (SI) units, typically square-metre kelvin per watt or m2·K/W (or equally, m2·°C/W). A different unit of measure is used in the USA, so please be aware if researching further.

U-value measures are also widely used to explain thermal performance. U-values and R-values are quite simply the inverse of one another.

See here for a R-value comparison table of different window material and technology options.

Yes, they are highly recyclable.

Yes, they represent exceptional value for money over their whole-of-life. No costly or environmentally damaging maintenance is required and their thermal performance outperforms aluminium (including thermally broken aluminium) hands-down, which equates to monthly energy bill savings in summer and winter. A warmer dryer home provides a more comfortable healthier environment meaning less sick days, greater productivity and less hospital admissions.

Yes. We have installed windows in high wind areas such as Mt. Cook Village, Twizel and Scott Base in Antarctica!

A common misconception is that PVC does not perform well in exposure to fire situations, when in fact it achieves a European reaction to fire classification of DIN EN 13501-1 Class E. PVC is an inherently fire resistant plastic, the only exception among the general-purpose plastics.

When PVC products are burned, hydrogen chloride gas resulting from thermal cracking slows down the continuous combustion reaction and prevents burning progress by warding off the PVC product surface from oxygen in the air. The gas is also detectable by its highly unpleasant odour at concentrations well below those that could be harmful to health. This feature allows early detection of a fire.

During manufacturing at our factory in Christchurch, frame lengths are mitred and joined through a PVC welding process using heat and pressure. This results in extra strength and weather tightness.

Our own install teams (i.e. they are employees of NK Windows) installs most windows and doors well sell and often travel around the South Island to do so. We do offer a supply only arrangement if you want your builder to install and we also have qualified regional partners that will install on our behalf in instances where it is not economically viable for our Christchurch-based teams to travel.

Yes. Consideration should be given to placement of curtains and blinds to allow for inward opening. Alternatively our windows and doors are well suited having blinds fitted to the sash. We partner with Cosiflor to provide TwinGo Blinds that are specifically designed for PVC frames.

Yes. We partner with Homeplus who offer a variety of styles and functional designs that work very well with inwards opening windows and doors.

There are 3 main reasons:

  • Sealing – the multi slide door only slides, so sealing is limited to dual brush-type seals on all 4 sides. Multi slide doors (regardless of frame material) should be avoided where exposure to medium to high wind is common. The lift & slide door has a double movement which means the moving door is not immediately adjacent to stationary elements. In this case, dual rubber seals are used on all 4 sides and during the closing process the door drops down on the seals creating a tight enclosure. The lift & slide door offers superior sealing resulting in significantly better thermal and noise insulation plus blocking of draughts.
  • Security  the multi slide door offers a good level of protection against forced entry. However the lift & slide door drops down into grooves making leverage very difficult, creating a much more secure door.
  • Size – the lift and slide door is able to be manufactured in very large sizes, so is ideal for unobstructed views.
  • Other – both the lift & slide door and multi slide doors can be floor flush mounted.

There are 2 main reasons:

  • Sealing – the multi slide door only slides, so sealing is limited to dual brush-type seals on all 4 sides. Multi slide doors (regardless of frame material) should be avoided where exposure to medium to high wind is common. The tilt & slide door has a double movement which means the moving door is not immediately adjacent to stationary elements. In this case, dual rubber seals are used on all 4 sides and during the closing process the door presses tightly against the frame creating a very tight seal. The tilt & slide door offers superior sealing resulting in significantly better thermal and noise insulation plus blocking of draughts.
  • Security – the multi slide door offers a good level of protection against forced entry. However the tilt & slide door has locking points on all 4 sides making leverage very difficult, creating a much more secure door.
  • Other – the multi slide door can be floor flush mounted; however the tilt & slide has a step-over sill.

Absolutely. Half the windows we install are renovation jobs. We can provide windows with or without reveals. The bulkier PVC frame is ideal for maintaining the character of bungalows and villas.

Yes, no problem. Triple glazing can improve the thermal performance by over 35% compared with double glazing.

Yes. We carry several models in stock and can source others if required including micro-chip controlled access for up to 10 cats.

If you want to achieve an airtight seal, optimise thermal performance from the glass & frame and get good value for money, then no, it’s not a good idea.

  • Double-glazing adds a lot of extra weight to a window that the original sash and hardware were never designed to cope with. Sagging along with poor sealing are typical problems people will face after a short time.
  • Adding double-glazing does not address the issue of poor performing frames in terms of aluminium being a good thermal bridge and poor sealing.

The sun radiates ultraviolet (UV) light, visible light and infrared (IR) light. UV 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  and it too contributes to fading. UV does the majority of the damage.

There are 5 options to protect against fade damage:

  1. Laminate glass blocks 99% of UV light whilst still allowing high levels of visible light to enter the room. Clear glass blocks 48% of UV light.
  2. Tinted glass blocks 79% of UV light, however rooms will become a lot darker as visible light transmittance drops by 44%, plus solar heat gain drops by 32%.
  3. Low E coatings (primarily used for heat retention) block 58% of UV light whilst still allowing high levels of visible light to enter the room.
  4. External shutters, louvres or blinds.
  5. Internal blinds.

Under normal circumstances you will not need a builder if replacing windows and doors, we will do it all. However, we do not do structural work, so in the event of structural work being required, the services of a builder will be required.

Your new windows and doors will be completely sealed and watertight. In most instances we will fit a custom cut piece of Colour Steel flashing to cover your wooden exterior sill. There are many colours to choose from and can be painted at a later time if required. There are several examples available to view here http://www.nkwindows.co.nz/our-clients/renovations/

© Copyright NK Windows 2017   |  
Website by Plato Creative