{"id":1396,"date":"2015-05-13T08:39:16","date_gmt":"2015-05-13T08:39:16","guid":{"rendered":"http:\/\/vertia.fi\/?page_id=13"},"modified":"2023-11-01T09:51:03","modified_gmt":"2023-11-01T07:51:03","slug":"ilmanvuotoluku","status":"publish","type":"page","link":"https:\/\/vertia.fi\/en\/tiiveysmittaus\/ilmanvuotoluku\/","title":{"rendered":"Air leakage rate"},"content":{"rendered":"

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Leak test<\/a> The result is a building air leakage rate qE50<\/strong>. The air leakage rate indicates the amount of air leakage relative to the surface area of the building envelope (floor, roof, exterior walls, including doors and windows). The lower the number, the better the airtightness.<\/p>\n

Air leakage rate qE50 =<\/div>
How many cubic meters (m\u00b3) of air leak through one square meter (m\u00b2) of the building envelope per hour when the pressure difference is 50 pascals? The actual air leakage rate under normal conditions is lower, since when ventilation is set to normal levels, the dwelling is very close to a zero pressure difference.<\/div><\/div>\n

The air leakage rate is used to calculate a building\u2019s energy consumption and heating power requirements, and when preparing an energy certificate during the building permit phase. If a value lower than 4 is to be used, the airtightness of the building must be demonstrated through an airtightness test or, in the case of prefabricated homes, through a so-called declaration procedure, which is now a rather rare practice. The air leakage rate planned during the design phase is therefore usually verified by an airtightness test before the building is completed, and the measured air leakage rate is updated in the energy certificate. A good airtightness rate demonstrated by measurement is also a valuable document when considering the resale of the home.<\/p>\n

A low air leakage rate is easily achieved by carefully sealing the building envelope, so a good airtightness rating is, above all, an indicator of construction quality. It also signifies a low risk of moisture and mold damage and helps reduce drafts. In an airtight house, ventilation also works better, as uncontrolled air leakage does not occur through the structures. A modern, energy-efficient house consists of thick insulation, mechanical ventilation with heat recovery, and excellent airtightness. In particular, all three components of this triad must function well for the system to work effectively. This ensures that the structures remain sound, the indoor air stays clean, and the building achieves high-quality energy efficiency. In an airtight house, the ventilation system must be in continuous operation.<\/p>\n

The Effects of Airtightness on Energy Consumption<\/h2>\n

Use the calculator below to estimate the impact of airtightness on a building\u2019s energy consumption. The calculator is based on the Ministry of the Environment\u2019s decree on the energy efficiency of new buildings and is intended as a guide.<\/p>\n