What is BS EN 13141-8 - Performance testing of un-ducted mechanical supply and exhaust ventilation units about? 
BS EN 13141 is a European Standard that discusses the performance testing of components/products for residential ventilation.
BS EN 13141-8 is the eighth part of the series that specifies test methods on ventilation system package and permits to avoid tests on each component separately.
BS EN 13141-8 specifies methods for the performance testing of components used in residential ventilation systems to establish the performance characteristics as identified in EN 13142.
BS EN 13141-8 specifies the laboratory test methods and test requirements for the testing of aerodynamic, thermal and acoustic performance, and the electrical power of an un-ducted mechanical supply and exhaust ventilation unit used in a single room. The purpose of BS EN 13141-8 is not to consider the quality of ventilation but to test the performance of the equipment. It is assumed that better values are achieved on-site when the ventilation system package is installed in accordance with the manufacturer's instruction and within the limits of the test conditions given in BS EN 13141-8
Who is BS EN 13141-8 - Performance testing of un-ducted mechanical supply and exhaust ventilation units for? 
BS EN 13141-8 on un-ducted mechanical supply and exhaust ventilation units is relevant to: 
- Ventilation and air-conditioning system manufacturers and designers
- Ventilation product/component manufacturers and designers
- Quality control and testing personnel
- Architects and contractors
- Residential building developers and planners
Why should you use BS EN 13141-8 - Performance testing of un-ducted mechanical supply and exhaust ventilation units?
Indoor air is kept clean and fresh with proper ventilation systems, that ensure that fresh air enters and bad air exits, such that moisture, smells, gases, dust, and other contaminants are removed. For this reason, it is essential that the exhaust ventilation system be tested for optimal performance and effectiveness, to make living spaces comfortable for its inhabitants.
BS EN 13141-8 provides you with best industry performance testing of aerodynamic characteristics, external leakages and electrical power.
By complying with BS EN 13141-8, you can ensure the un-ducted mechanical supply and exhaust ventilation units, are fit for purpose and that they play a positive role in the performance of the overall mechanical ventilation systems. As a result, incidents of product failures can be minimized.
What’s changed since the last update?
BS EN 13141-8:2014 supersedes BS EN 13141-8:2006. BS EN 13141-8:2014 includes some editorial changes with respect to BS EN 13141-8:2006. These include: 
- Alternating ventilation units including a storage type heat exchangers have been included
- Measurement of the deviation of air flow rate due to façade pressures in normal use has been introduced
- Temperature conditions have been modified to be the same as in EN 13141-7 that is to say 7 °C / 20 °C
