How to tag air terminals in Revit

Load a tag family that matches the Air Terminals category, then use Annotate > Tag > Tag by Category to tag a diffuser or grille. For the remaining visible terminals, use Annotate > Tag > Tag All and choose the air terminal tag category. I'd place and check one tag first because its label may read a different parameter from the one your mechanical plan needs.

The controls below follow full Revit 2027 in English on Windows. Revit LT isn't intended for MEP engineering modeling; these steps assume a full Revit mechanical project with air terminals already present.

Separate the terminal data from the tag's label

The terminal is the model element. The tag family defines the label that reads its parameters, and the placed tag identifies that terminal in a drawing. Changing the information a label displays and changing the terminal's information are different actions.

Set it here	It changes	Choose it when
Tag family's label	Displayed fields	Choosing what to report
Terminal parameter	Model value	Correcting verified data
Placed tag / leader	Drawing position	Making the view legible

Tag labels read the corresponding element parameters. Choose a field that matches the information required on the plan and in its existing schedule. Don't substitute Type Mark for Mark, or add a flow field, just because another project's tag uses it.

Load the tag for the correct category

Open the mechanical view containing the terminals you want to annotate and check that the terminals you need are visible. Tag All works on visible elements in the current view, and Tag by Category needs a terminal you can highlight, so a ceiling diffuser that doesn't show in a floor plan can't be tagged there.

When terminals are missing, work through Autodesk's checklist for objects that aren't visible in this order:

• Click Reveal Hidden Elements on the View Control Bar. Terminals hidden in this view display in color; select one and use Unhide Element or Unhide Category.
• Open View > Graphics > Visibility/Graphics and confirm the Air Terminals category is visible and no applied filter hides it.
• On the Properties palette, click Edit for View Range. Elements outside the view range don't display, so compare the plan's range with the height of the terminals.
• Tag ceiling terminals in the reflected ceiling plan when that is the view the drawing set uses. An RCP looks up from its cut plane, and tags placed in the floor plan don't appear there, so run Tag All in the RCP itself.
• For terminals in a linked model, make sure the link is loaded, then check the Revit Links tab of Visibility/Graphics: the link's Visibility check box, and Display Settings set to By Linked View or Custom, which can keep the terminals out of the host view.

Once the terminals show, open Annotate > Tag panel drop-down > Loaded Tags and Symbols.

1. Look for the annotation style associated with Air Terminals.
2. If the required family isn't loaded, click Load and browse to an appropriate tag family.
3. Check the style shown beside the category. Use its drop-down to choose the required default if several styles are loaded.
4. Click OK.

The project template determines which tags are already loaded. The last style loaded for a category becomes its default unless you change it, so check the assignment before placing tags across the view. Use the family supplied for your project standards; there's no single installed filename that every template must use.

In Revit 2027, Multi-Category tags can also be defaults for supported categories. Tag by Category uses the assigned default, and Tag All Not Tagged follows the category organization and defaults in Loaded Tags and Symbols. Check the assigned style even when you already have an Air Terminal Tag family loaded.

Place one tag, then tag the remaining terminals

Choose Annotate > Tag > Tag by Category. While the tool is active, set the orientation and choose Leader on the Modify | Tag tab or in the Properties palette if the tag needs one. Highlight the terminal and click to place the tag. You can reposition the tag and leader after placement.

Compare that first label with the terminal's corresponding value and the same field in an existing schedule. Check that an instance field identifies the individual terminal, or that a type field reports the correct type information. A familiar-looking tag symbol doesn't establish that its label reads the right parameter.

Once the first tag reports the right information, use Tag All Not Tagged for the rest:

1. Keep the target view open. Select a subset of terminals first if you only want to tag those elements.
2. Choose Annotate > Tag > Tag All.
3. In Tag All Not Tagged, choose All objects in current view or Only selected objects in current view.
4. Select the air terminal tag category. Set Leader, Leader Length and Tag Orientation as needed.
5. Click OK, then review the tag positions and reported values in the view.

This operation applies to untagged elements in the selected scope of the current view. If Revit reports that the tag category or its object type is hidden, click OK to let Revit turn on visibility. If an assigned view template blocks the tag category, click OK to open Assign View Templates and resolve the relevant visibility before tagging.

When the drawing standard calls for one tag on a group of identical diffusers instead of one tag each, attach the extra terminals to a single tag. Start Tag by Category, then click Modify | Tag > Host > Add / Remove Host, click each terminal the tag should cover and click in empty space to finish.

Each host gets its own leader. After the first leader, a window selection keeps only elements of the tag's category, and Modify | Tag > Leaders > Merge Leaders snaps the leaders together. The same Add / Remove Host tool adds or drops hosts on a tag that is already placed. To print how many terminals the tag covers, add Host Count to its label, as shown in the Edit Label steps below. Multi-leader tags arrived in Revit 2022, and Revit 2023 added Add / Remove Host during tag placement.

For terminals you haven't placed yet, Systems > HVAC > Air Terminal has Tag on Placement on the ribbon, which adds the tag as each terminal goes in. The annotation still needs the same parameter check.

Edit the label when it reads the wrong information

Select a placed tag and choose Modify | <element> Tags > Mode > Edit Family. In the Family Editor, select its label, then use Modify | Label > Label > Edit Label. To add a label, use Create > Text > Label and click to place it.

In Edit Label, Label Parameters lists the fields displayed in the label. Select the unwanted field there and click Remove Parameter. Keep any other fields the label needs. Select the required field in Category Parameters, then click Add Parameter to include it in Label Parameters. For a tag with several hosts, pick Multi Leader Tags in the category drop-down and add Host Count the same way.

Parameter options vary by category. Use only fields available for this tag and host. A Flow field isn't universal, and neither are size or Type Mark fields. Click OK when the definition is ready.

Start with the terminal, not the tag, when a Flow label reads 0 or stays blank. Select the terminal and read the same parameter in Properties. If it shows 0 or nothing there too, the label is reporting the model correctly: a diffuser's air flow comes from its HVAC connector's Flow Configuration, which defaults to Preset, a user-defined value, while System assigns a share of the system air flow through Flow Factor. That value belongs to whoever owns the mechanical design. If Properties does show a value, check that Label Parameters holds that same parameter and how Edit Label formats it.

Save the revised tag family under a separate name so the original remains available. Return to the project and load the saved family through Loaded Tags and Symbols. Select its style as the category default for subsequent placements. The existing tag needs a separate change.

Select the original placed tag in the drawing area, then choose the corrected tag style in the Type Selector. Compare the value on that same tag with its host and the corresponding schedule column before using Tag All. The family editing workflow covers broader family changes; keep this edit focused on the annotation label.

Take care when clicking an editable label in the project: editing it can change the element's parameter value. A label containing several parameters can open Change Parameter Values. Correct the tag definition when the presentation is wrong; don't alter design airflow or other engineering data to make the annotation look right.

Tag terminals in a linked model from the host view

Revit supports tagging linked and nested model elements from most categories in a host-model view. Confirm that the terminal category is available in this view. Use Tag by Category for a controlled selection, or select Include elements from linked files in Tag All Not Tagged. Check that the tag refers to the correct linked terminal.

Keep corrections to linked source data in the model that owns that data. If a tag becomes orphaned, Revit remembers its previous host and can rehost it when that host becomes available again. Check the link and host before replacing a tag that has lost its reference.

The route stops at what the host view can display. Terminals in an unloaded link, or in a link whose display settings hide them, stay out of reach of Tag All until they show, and Revit LT tags elements in links but can't customize linked-model visibility. When the next task concerns the system rather than its tags, continue with the MEP model workflow; the structure and MEP guide archive holds the related pages.