ECOWINDOWS is a pioneer in the field of Passive Houses. In 2011, we manufactured the first certified Passive House windows right here in Aotearoa and in 2012 the first ever Passive House in New Zealand and Australia was built with our double-glazed, high-performance windows. This first NZ Passive House project was completed with a controlled ventilation system, that helps to keep the house dry, warm and comfortable all year round. The result is a beautiful and sustainable home with dramatically reduced power bills for years to come.

ECOWINDOWS has a vast variety of German windows available, which are all suitable for the high standards and requirements of Passive Houses. Next to sustainable materials, such as wood and aluminium, we offer a wide range of high-performing PVC windows.

As a member of the “Passive House Institute New Zealand” (PHINZ), ECOWINDOWS contributes to the mission of creating healthy and highly energy-efficient homes for all New Zealanders.

Passive House design originates in Germany and uses a combination of high-performance double or triple glazed windows, insulation and airtightness to regulate the internal temperature. Utilising only the natural power of the sun, a Passive House creates stable temperatures of cosy 20°C all year round, day and night, while the outside temperature varies and can drop well below 5°C in winter.

A certified Passive House must meet high building standards and has to include the following components:

• Good insulation to reduce overheating and extensive heat loss
• Double or triple glazed windows and high-quality doors to keep the heat inside
• Eliminate thermal bridges and cold areas in the walls
• Create an airtight building that does not let any air in or out
• Regulate and control the airflow in the house with a Heat Recovery Ventilation system

The effectiveness of windows and their environmental performance is measured in U-value or R-value, which both describe the amount of heat loss of a material (R is actually the reciprocal of the U value: R = 1/U).

The U-value describes how effective a material is as an insulator. Better-insulated structures have a lower U-value and lose less heat. The R-value defines the ability of a material to resist heat flow. In contrast to the desired low U-value, a higher R-value indicates a better performance and a better insulation. The effectiveness of windows is usually calculated internationally as U-value, but in New Zealand the R-value is still widely used.

ECOWINDOWS products are made with decades of experience of energy-efficient building in Europe, where PVC windows are the most common building solution. Even our standard double-glazed windows achieve much lower, and thus better, U-values and reduce the heat loss significantly, compared to standard NZ windows.

Germany has a long history of very strict and rigorous government regulations regarding the energy efficiency of newly built and existing homes (the so called EnEV law). These principles focus on the high quality of insulation and the low heat loss rates that ensure that houses are kept warm and cosy, without creating hefty power bills.

The German EnEV law regulates the required U-value rates for each area of a house, including the windows, because they play such a big part in energy-efficient building. This means that only double-glazed windows with a low Uw-value (which means the overall U-value of glass, profile and edge spacer) of 1.30 can be installed in German houses (as a minimum requirement). Today, however, triple-glazed windows with even better U-values are the standard in Germany (which, by the way, ensures that we can offer very reasonable upgrades to triple glazing). For comparison, New Zealand’s commonly used single-glazed windows have a very high U-value of about 5.0, which means that most of the heat in the house is lost through the windows.

ECOWINDOWS only offers windows that match the strict requirements and the high standard of the German market to create dry, warm and healthy homes here in New Zealand.

ECOWINDOWS only uses windows with double-glazing or triple-glazing, as they achieve a much better thermal insulation compared to the traditional, and most commonly used, New Zealand single-glazed windows.

Modern double-glazed windows are made of two thermally insulated window panes (Low-E glass) that have a hermetically sealed space in between them. This space reduces the heat loss significantly, because it is filled with Argon, rather than air, a noble gas with low heat-conducting properties. Triple-glazed windows are made of three layers of glass, each covered with a Low-E coating and an Argon filling in between them.

A spacer seals the void between the two or three layers of glass to ensure that no gas or air can get through either way. The more layers of glass a window has, the better the energy efficiency of your home is, as the amount of heat loss is drastically reduced with each pane of glass.

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