A Comparison of Kiwi and French Methods in Creating Airtightness in a Home

28 February 2017
Posted by: Evolution and Lucas Frestel
Time to read: 3 min

In order to continually improve our construction processes and to provide you the best you deserve, Evolution asked Lucas Frestel, a French Engineer completing an internship at Rilean Construction, to compare the Wincon Test we use with the French method of checking airtightness in a house.

A Comparison of Kiwi and French Methods in Creating Airtightness in a Home

by Lucas Frestel, M.S. Engineering, ITCBTP Montpellier.

Basically, to have a comfy and healthy home, you must make it warm and dry.

Most people think that good insulation is the only feature that can guarantee this comfort.

But, physics studies show that 50% of heat loss (or heat rise) happens when there is a lack of airtightness in the thermal envelope of the home.

To prevent that, membranes, like Proclima's Intello and Sollitex, are used to seal the house, which provide airtightness to the whole building.

During my internship at Rilean Construction in February 2017, I participated in conducting a Wincon Test, to identify and address any air leakage after the Proclima membranes have been installed, but before the GIB goes up. We preformed this test on one of the homes currently in construction in Jack's Point, Queenstown.

The Wincon Test is a test performed during construction and will be followed after the home is built with The Blower Door Test, a computerized test that records in air-changes-per-hour (ach) the number of times the air replaces itself with that time frame.  This score reflects potential heat loss, with a 0 ach indicating perfect airtightness and an absolute minimum loss of heat and 9 ach poor airtightness and extreme loss of heat.

This score is a criterion to determinate if the house is energy efficient or not.

In Evolution homes, we aim to achieve <3 ach, which corresponds to the German standard in the Energy Efficient regulations.

As a reminder, most modern homes built in New Zealand generally score between 6 and 9 !

Lucas wincon test chart

This chart shows the most susceptible areas in a home that can be sources of leaks. As you can see, the electrical installation creates leaks practically every time, which means we are particularly careful to seal up every penetration in or through the exterior walls.

The process is quite simple but ingenious:

gary wincon test3

Gary Dent affixing fan to exteriour door for Wincon Test

•             The house needs to be pressurized from the inside with a big and powerful fan which is fastened to one of the doors.

lucas wincon test2

French Engineering intern, Lucas Frestel, performing a Wincon Test


•             Once the house is pressurized, the goal is to check every window and every door or joint that could be a source of air leakage with a smoking incense stick.


Wincon Test incense rising

•             If the smoke rises naturally, that means there is no leak and that the membrane has been installed properly, but if the smoke is pulled in the direction of the window or joint, it means that there is a leak in this area.  Once the weakness is noted in the envelope, it is sealed with a specialized polyurethane foam or tape.

intello tape

Specialized tape for sealing Proclima Intello membrane


Like Germany, France’s regulation in residential construction is demanding and one of the precursors to the international standards of energy-efficient construction.

The Evolution Wincon Test is similar to the process used in France, with a minor difference in the technique used to find leaks.

Whilst Evolution uses smoking incense sticks to identify potential penetrations in the envelope on the inside of the building, the French method requires two operators as the house is depressurized and smoke enters weak spots from the outside.

The end result is the same, giving builders the opportunity to address any areas of weakness and ensure maximum airtightness in the home.


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