Zones

Zones group spaces that share common HVAC equipment. A zone typically represents all the spaces served by a single thermostat or terminal unit.

Zone Concepts

What is a Zone?

A zone is a collection of one or more spaces that are:

• Controlled together by a single thermostat
• Served by a common terminal unit (VAV box, fan coil, etc.)
• Expected to have similar thermal conditions

Single-Space Zones

Many designs use one zone per space for:

• Maximum control flexibility
• Spaces with varying loads
• Critical comfort requirements

Multi-Space Zones

Combine spaces into zones when:

• Spaces have similar loads and schedules
• Cost constraints limit the number of zones
• Spaces are thermally connected (open plan)

Creating Zones

Automatic Zone Creation

HVAKR can automatically create zones from unzoned spaces:

1. Navigate to Building Model > Zones
2. Click Auto Create Zones (the wand icon) in the toolbar
3. HVAKR groups unzoned spaces into zones immediately — there is no strategy dialog — and shows a toast with how many zones were created and spaces assigned
4. Review the results on the canvas and adjust zone membership as needed

Create a Zone

1. Navigate to Building Model > Zones
2. In the Zones panel, click Create Zone (or press N)
3. A new zone named New Zone is added and selected automatically
4. Rename it and set its color in the Zone Data panel
5. Assign spaces to the zone (see below)

Zones are created empty — there is no space picker at creation. Assign spaces afterward using Assign Spaces.

Assigning Spaces

Assign Spaces to a Zone

1. Select a zone in the Zones panel
2. In the Zone Data panel, click Assign Spaces
3. Click spaces on the canvas to toggle their assignment — the hint bar reads Click a space to toggle zone assignment
4. Assigned spaces appear in the zone’s Spaces list; remove one with the ✕ button
5. Click Done when finished

A space can only belong to one zone.

Zone Properties

Zone Name

Use descriptive names that indicate:

• Location (East Wing, Floor 2)
• Function (Conference Rooms, Open Office)
• System (AHU-1 Zone 3)

Space Assignments

The list of spaces in this zone. Shows:

• Space names
• Space areas
• Space loads (when calculated)

Zone Load

The sum of all space loads in the zone. This determines:

• Terminal unit sizing
• Supply airflow
• Heating/cooling capacity

Zone Airflow

Peak Airflow

The maximum airflow required by the zone, based on:

• Peak cooling load
• Minimum ventilation requirements
• Heating airflow (if applicable)

Minimum Airflow

The lowest airflow the zone can receive:

• Ventilation requirements (ASHRAE 62.1)
• Minimum turndown ratio
• Heating airflow in VAV systems

Diversity

When zones peak at different times:

• System airflow may be less than sum of zones
• Diversity factor accounts for this
• Important for central equipment sizing

Zone Types

Interior Zones

Zones with no exterior exposure:

• Cooling-only in most climates
• Dominated by internal loads
• Relatively constant load

Perimeter Zones

Zones along the building exterior:

• Both heating and cooling loads
• Affected by solar and transmission
• Variable loads throughout the day

Special Zones

Zones with unique requirements:

• Conference rooms (variable occupancy)
• Server rooms (high cooling load)
• Laboratories (special ventilation)

Best Practices

1. Match controls - Zones should correspond to control zones
2. Consider orientation - Separate perimeter zones by exposure
3. Account for load diversity - Similar spaces can share zones
4. Plan for flexibility - Future changes may require zone modifications
5. Check ventilation - Ensure zones meet outdoor air requirements