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ThermaDura provides a range of low maintenance and high performance window systems for conservatories, orangeries and sunrooms. We are always striving to provide the best, most energy efficient products in the market.


Passive House is not a brand name, but a building standard and construction concept for energy efficiency, comfort and affordability. A passive house provides consistent, comfortable temperatures in Winter and Summer, avoiding heat loss and drafts in Winter and avoiding solar gain in Summer. Only a selected number of New Zealand window suppliers produces joinery suitable for Passive Houses. Certification is achieved by retaining a U - Value of less than 0.8W/M²K beside other performance requirements.


Windows in a Passive House are designed, oriented, and installed to take advantage of the free passive-solar energy that can be gained through them. Passive House windows and doors are extremely well built incorporating, tightness, thermal breaks, minimal air infiltration and ex filtration – all of which leads to extraordinary high R-values. The R-value is further enhanced by using low-emissivity (low-e) coatings on the window glazing. These are microscopically thin, transparent layers of metal or metallic oxide deposited on the surface of the glass. The coated side of the glass faces into the gap between the two panes of a double-glazed window. The gap is filled with low-conductivity argon or krypton gas rather than air, greatly reducing the window’s radiant heat transfer.


This allows Passive House designers to select from an arsenal of incredibly energy efficient windows that allow for high, moderate, or low solar gains, providing a range of options for houses in all climates, from heating dominated to cooling dominated. The Passive House window eliminates any perceptible cold radiation or convective cold airflow, even in periods of extreme weather.

At ThermaDura we offer timber and timber-aluminium passive house windows and doors for our conservatories and conservatory walls.

Passive House Conservatories


The benefits of choosing a Certified Passive House are significant:



  • Extremely low energy use:

    • 90 - 95% less heating and cooling energy use, 60-80% overall energy savings compared to a NZ Building Code compliant building

  • High quality indoor air:

    • Controlled ventilation for a continuous, consistent supply of fresh, heated, outdoor air

  • Comfortable indoor temperatures:

    • A minimum of 20ºC all year-round, resulting in a dry, warm, healthy building

  • Operational and construction savings:

    • Vastly reduced energy bills; elimination of conventional HVAC systems; much smaller solar systems required to reach zero energy; durable, tight building shell for lower maintenance

  • Proven sustainability:

    • 30,000+ buildings worldwide, some zero and even positive energy. 25 year track record.

  • Helping the earth:

    • With buildings contributing 30% of all greenhouse gases, Passive Houses are exponentially friendlier to the environment because of their minimal energy & fossil fuel consumption.

For more information about Passive Houses, please check the website of the Passive House Institute Of New Zealand:

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