Blower Door

Blower Door test

We provide Blower Door test – to help determine a home’s airtightness. The testing method is in accordance with ČSN EN ISO 9972. We are authorised provider of the Nová zelená úsporám project.

The Blower Door test is mostly required for passive and low energy consumption houses. We recommend to make the test during the building process, just after installation of all windows and entrance doors. At this time it is quite simple to detect and repair possible leaks. Before the test, we prepare the building by temporarily sealing air-conditioning conduits, woodstove air inlets, drain outlets etc. During the test we lower or increase the air pressure inside the building (pressure range 20 – 70 Pa). The result including the n50 value is protocoled.
We measure also apartment buildings and industrial objects, where more measuring sets are needed.

Three flats measurement

Use of two fans

Measuring with three fans

Together with the test we offer detection of air leaks. We use several methods (except initial palm detection):


Smoke pencil

Thermal imaging camera

We can advice how to fix and seal leakes.

What we need from you:

  • House documentation to determine inside cubic capacity and floor area. If not available, we will measure on spot.
  • Details of air inlets and outlets of the ventilation. These must be temporarily sealed during the test.

Buildings readiness:

Duct leakage test:

For the right functioning of air exchange it is important to have right installation of duct conduits. To check how good they are we use special measurement instrument Minneapolis DuctBlaster.

Price list:

  • Blower Door test with full protocol for “NZÚ”: 4000Kč/per house
  • Blower Door test without protocol: 2500Kč/per house
  • Blower Door test of huge objects and apartment buildings: price calculated individually
  • Duct conduits check: 3000Kč/per family type house, bigger buildings: price calculated individually
  • Air leaks detection: 350Kč/h
  • Project consultancy, air leaks repairs: 350Kč/h
  • Transport: 5Kč/km
  • We aim to solve possible air leaks immediately on spot.
Sample Protocol