Ventilation and Air Conditioning: Ducts, Extract Fans, MVHR and Split Systems

Its three tools

Open **CAD tools** in the tool rail and then **Ventilation**. The group has three tools, and each has a command you can type.

**Catalogue** (`VENTILATION`): browse the trade's fittings by system, with each one's plan symbol. Picking one arms Place with it.

**Duct** (`DUCT`): draw a run. Click each point; press Enter to finish. The run starts on the trade's usual size, and its size, system and levels are in its panel afterwards.

**Place** (`PLACEAIR`): put down the fitting you picked. Each fitting stands at its usual height, which its panel can change.

A run snaps to the connection points (ports) of fittings, so a pipe or a cable that starts on a fitting is joined to it. A fitting that should be connected and is not is listed in the Issues tab as not connected.

What is in the catalogue

**Ventilation**: MVHR units, inline and centrifugal fans, transfer grilles, external louvres, silencers, filters, humidity sensors.

**Dampers**: balancing, volume control, fire, smoke, fire and smoke, relief and backdraft dampers.

**Extract**: extract fans.

**Air conditioning**: supply diffusers, return grilles, registers, air handlers, split systems and units, rooftop units, VAV and CAV boxes, cooled beams, chillers, dehumidifiers, humidifiers and coils.

**Refrigeration**: compressors, condensers and evaporators.

Ducts

**Shape**: round or rectangular, with its size. A rectangular duct shows its **Aspect** and the **Equivalent round** it matches.

**Air**: a duct's panel shows the air through it and its speed. The air is read from the terminals behind it, back to the fan or unit that serves them.

The checks

**Shape**: a rectangular duct flatter than 4 to 1.

**Speed**: a duct too small for its air, so the air runs too fast and noisy.

In 3D and on paper

**3D**: runs are built as real cables, pipes and ducts at their levels, and fittings stand at their mounting heights. In 3D you can drag a run's end or its body, and it snaps to corners and to other fittings' ports.

**Through walls**: a run that crosses a wall or a floor cuts its own hole through it, and the hole moves with the run.

**Showing and hiding**: the Layers tab has a switch for each trade, and an X-ray switch that shows the services through the building.

**Sections**: a run cut by a section is drawn as its section, and the ones beyond it along their line.

**Schedules**: the Schedules tab lists runs by size, fittings by kind and boards by circuit. See [Sheets and schedules](/docs/sheets-and-schedules).

Read next

• Plumbing and heating
• Electrical
• Checks and issues
• Sections and elevations

Frequently asked questions