A better approach to creating manufacturer air handling unit (AHU) Revit families using a single sophisticated and flexible module.

Last week we released a collection of Revit content for Passive House air handling units. These were modular AHUs from Menerga and Zehnder that have been certified by the Passive House Institute. Today we will delve into the technical aspects of how we created our Passive House AHU Revit families using a single base family.

Problems with Manufacturer AHU Revit Content

All of our Passive House AHU content is adapted from a single Revit family we created for a UK engineering company back in 2020. The motivation for making that family came from too much past experience dealing with manufacturer AHU models.

Especially when working on large projects, it's never nice to be on the receiving end of 20+ manufacturer AHU zip files. These are typically over-detailed DWGs that require a fair amount of cleaning up in order to make them useable. Then the AHUs may get re-sized, or the ventilation systems may get re-designed down the line, which means going through the whole process all over again.

Alternatively, sometimes you receive an AHU Revit family only to find out it's just nested CAD blocks with no connectors. Or even if it has connectors, its geometry may be too simple to use in a section or plan view. This then forces you to use an imported DWG file, slowing down your workflow.

A Better Approach Using Nested Families

Modular air handling units are perfect for using a nested Revit element. We started by creating a single sophisticated and flexible module that can change into any AHU component type, such as coil, filter, heat exchanger or even fan with duct connection.

This multi-purpose module can then be nested and duplicated many times without having a significant effect on file size. The nested family contains all the 3D and 2D geometry, so it's really just a case of configuring each component and aligning them. Once all the modules are configured, then we only need to add the connectors.

The goal for our master AHU Revit family isn't to have a "super family" with so many options that you end up thinking, "Damn I miss my DWG import!" Rather, the master family is designed with the following aims in mind:

  1. Simple geometry but with enough 2D to look good in deliverables.
  2. Smooth workflow within Revit projects.
  3. Easy to maintain with minimal effort.
  4. Shows details that are important for MEP coordination such as coil location and clearance zones.

A lot of the time involved in creating our master AHU module went into building the controls for the frame. With modular air handling units, you will often find some modules share the left or right frame of the adjacent module. Or on AHUs with a heat recovery fly wheel, for example, the frame may need to spread the entire width and height of the AHU to encompass all four air systems.

Some air handling units will still call for adding specific geometry to the host family. Typically, these are items that can differ from one manufacturer to another, such as base construction.

Once one AHU Revit family is created with all the required connectors, it becomes easy to adapt this to cover another manufacturer model. Any updates to the makeup, such as the addition or removal of modules, take just seconds to achieve.

Complete modular AHU Revit family in plan view.
Complete modular AHU Revit family in plan view.
Revit render of a Menerga modular air handling unit.
Menerga modular air handling unit.

Need Content?

If you company is looking for quality Revit content at an affordable price, give us a shout at hello@kinship.io. We'll be happy to provide a free, no obligation quote for your needs.