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Married couple became first in Norway to build a zero-energy home, saving heating costs and benefiting the environment.

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Gjerdrums vei 19,
Pb 4215 Nydalen,
NO - 0401 OSLO

Phone: +47 22 02 40 00

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Hemato Eiendom as

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BGM Arkitekter

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After 26 years in the home they built themselves, Wencke Nordli and Martin Østensen decided to venture into a new house project in Froland, Norway. This time they wanted something different. "We liked the idea of a maintenance-free home with ultra low energy consumption and good functionality," explains Martin Østensen.

Heat out the window
The couple spent one year thoroughly researching construction and energy technology before making their decision and starting to build a zero-energy home. Such a building produces its own energy using solar collectors and solar cell panels. This means occupants are not dependent on external electric energy (on an annual basis). "Preventing heat from going out the window is obviously good for the environment, but we were also looking for an economic gain," says Martin. Last year the electricity bill for their former house rang in at NOK 35,000.


It takes courage to build a zero-energy house, but the couple didn't hesitate when the architect presented them with a full ROCKWOOL insulation solution.

This involved FLEXSYSTEM and the thinner Flexi A plates on the walls. The latter was also used in the roof structure along with RockTett vapour barrier and RockTett Tape, while I-plate A was used for the entire floor area. This solution spared the couple from having to build 'an extra house'.

Building a zero-energy house normally requires you to build two houses in order for the insulation to be strong enough. First you build a house with insulation to keep the site warm and dry, and then you build the real house inside. "FLEXSYSTEM spared us from having to do that, as the finished elements could just be put in place. We also avoided thermal bridges, achieved more airtight insulation and saved a lot of time and money. We even began to realise energy savings during construction," says Martin Østensen.

Despite the high efficiency Wencke and Martin experienced during construction, they have no plans to embark on any new building projects in the near future. "No thank you. Although it's called a zero-energy house, we can never be sure if it will take five or twenty years before the house reaches zero energy consumption, depending on the climate. Perhaps it will end up being an energy-plus building or a ultra low-energy building.

"In reality, building a zero-energy house requires you to build two houses. FlexSystem spared us from having to do that."Martin Østensen, home owner.