Rules for NRVU units

NRVU stands for Non-Residential Ventilation Unit

NRVUs are air handling units with a nominal airflow of over 1000 m³/h.

The Directive

The requirements in the Ecodesign Directive primarily relate to:

  • Fan power consumption (SFP)
  • Output of the used heat recovery

Even though the definition of the power consumption’s threshold values are somewhat complex, the minimum requirements for heat recovery are clearly defined and laid down as follows:

From 2018: Plate heat exchangers at least 73%, however, for liquid-coupled batteries only 68%.

As stated previously, the directive lays down specific requirements for electricity consumption (SFP). This is described in a formula which is dependent on a number of factors, including the actual temperature efficiency.

VEX overview

To make this easy to understand and use, EXHAUSTO has provided a table of step-by-step calculations on the basis of a nominal operating point. This table contains data for the VEX compact program. The link for the VEX overview is shown on the bottom if the page.

Calculation programs

Our calculation programs shows you whether a specific air handling unit meets the requirements of the Ecodesign Directive for a specific operating point. All EXHAUSTO NRVUs comply with the 2018 requirements.

The Ecodesign guidelines do not apply here:

In general, a ventilations system must comply with the Ecodesign Directive. In other words:

  • Ventilation for people = is covered
  • Process ventilation = can be exempt

The Ecodesign Directive guidelines do not normally apply to "clean” process ventilation, in corrosive environments, at air temperatures above 100°C and with the transport of combustible gases and vapours.
 Example of places where the Ecodesign requirements do not normally apply:

  • Industrial cooker hoods , where the ventilation system does not also cover the room ventilation (for people)
  • Data centres, server rooms
  • Recirculation unit (<10% outdoor air)

Read more here:

Implementation guide from EU (English)
FAQ about the Ecodesign Directive 2009/125/EC (English)


Local requirements

Individual EU country requirements for temperature efficiency are obsolete. They are replaced by the requirements in the Ecodesign Directive, whereas the requirements for SEL/(SFP) continue to apply in individual EU countries, since these apply to the completed ventilation system installation, incl. pressure drop in the ducts, fittings, roof cowls etc., i.e. the completed installation. 

An example is shown below of an Ecodesign declaration - here for VEX340T

Image of Ecodesign Declaration for Institute pages


Get free advice on ventilation products and system solutions

Export Requests:
Odensevej 76
DK 5550 Langeskov

Tel +45 6566 1236

Calculation programs

Use EXHAUSTO's free calculation programs for calculating ventilation plant and system solutions

Go to Calculation Programs
Vex overview

VEX Summary

Get a quick overview of our entire range of compact VEX air handling units with heat recovery.

View the VEX summary here