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Daylight Harvesting Strategies

Video Tutorial

Watch the companion video Chapter 10: How to Configure Daylight Harvesting and Photocell Settings for a visual walkthrough of these steps.

Overview

Daylight harvesting automatically adjusts electric light output based on available natural light. When sunlight is plentiful, fixtures dim down. When it's darker, they brighten. This maintains consistent illumination while significantly reducing energy consumption—often by 30-60% during daylight hours.

How Daylight Harvesting Works

The Process

  1. Photosensors in the fixture measure ambient light levels continuously
  2. As natural light increases, the fixture dims down
  3. As natural light decreases, the fixture brightens up
  4. The goal is maintaining a consistent light level on the work surface

Energy Savings

Spaces with good natural light can achieve 30-60% energy reduction during daylight hours. Savings depend on window orientation, time of year, and weather conditions.

Two Ways to Daylight Harvest a Room

There are two distinct ways to daylight harvest a single room. Use one approach or the other — do not run both in the same group, or the sensors will conflict and produce erratic dimming.

Option 1 — Per-Fixture (LLLC Sensors)

Each fixture that has its own integrated LLLC (luminaire-level lighting control) photosensor measures the light at its own location and dims itself individually. Fixtures near a window dim more than those deeper in the room, giving the finest-grained response.

  • Use when: your fixtures have integrated photosensors and you want each light to react to the daylight at its own position.
  • How: enable daylight harvesting on each photosensor-equipped fixture (see Enabling Daylight Harvesting below).

Option 2 — Group-Wide (Area Sensor)

A single ceiling/area sensor — CS107S, CS107D, or BCS107 — measures the ambient light for the room and performs daylight harvesting for every light in the group mapped to that sensor. The entire group dims together from one reading.

  • Use when: your fixtures do not have their own photosensors, or you want one uniform dimming response across the whole room.
  • Required: When you use an area sensor for group daylight harvesting, you must disable daylight harvesting on every other device in the group — leave only the single area sensor performing daylight harvesting. If more than one device in the group has daylight harvesting enabled, they will fight each other and dimming will be erratic.

Note

Daylight-harvesting support on area sensors is version-specific — see the device's own help article (CS107S, CS107D, BCS107) to confirm the model you have supports it.

Enabling Daylight Harvesting — Per-Fixture (LLLC Sensors)

This is the setup path for Option 1 above — each fixture harvests daylight individually using its own integrated photosensor.

Prerequisites

  • Fixture must have a photosensor installed or connected
  • Do NOT enable on fixtures without photosensors (causes erratic dimming)

Step-by-Step Instructions

  1. Navigate to the Lights page.
  2. Long press on a photosensor-equipped light.
  3. Tap the Sensor Settings icon.
  4. Locate the Daylight harvesting toggle and enable it.
  5. Tap the settings button beside the toggle to configure strategy.
  6. Select your preferred strategy.
  7. Tap Save.

Repeat for each photosensor-equipped fixture in the space.

Enabling Daylight Harvesting — Group-Wide (Area Sensor)

This is the setup path for Option 2 above — a single area sensor harvests daylight for the whole group.

Configure daylight harvesting on the area sensor itself (not on each light), then bind the sensor to the light group. See the device's own help article for the full procedure:

Required: Disable daylight harvesting on every other device in the group — leave only the single area sensor performing it. Multiple daylight-harvesting sensors in one group conflict and cause erratic dimming.

The three pre-defined strategies (and the Custom option) described below apply to both setup paths.

Daylight Harvesting Strategies

The system offers three pre-defined strategies plus a custom option:

Soft Strategy

Parameter Setting
Response speed Slow
Minimum dim level 50%

Best for: Independent offices, parlors, reception areas, executive spaces

Characteristics: Gentle, subtle light adjustments that minimize occupant awareness of changes. Prioritizes visual comfort over maximum savings.

Mild Strategy

Parameter Setting
Response speed Medium
Minimum dim level 30%

Best for: Open offices, classrooms, meeting rooms, retail spaces

Characteristics: Balanced approach offering good energy savings while maintaining occupant comfort. Most commonly used strategy.

Aggressive Strategy

Parameter Setting
Response speed Quick
Minimum dim level = Low-end trim (1% or 10%)

Best for: Storage rooms, warehouses, utility areas, back-of-house spaces

Characteristics: Maximizes energy savings with rapid response to changing light conditions. May be noticeable to occupants but appropriate for utility spaces.

Custom Strategy

Allows fine-tuning of individual parameters for specialized applications.

Custom Strategy Parameters

Parameter Function Guidelines
DH Min Dim (%) Lowest dim level allowed Set higher (50%) for comfort; lower for savings
Delay Time (S) Seconds to wait before dimming down Longer delays (30-60s) prevent rapid changes
Speed (100ms) How quickly fixture dims Higher values = slower, smoother transitions

Minimum Dim Level

The minimum dim level (DH Min Dim) sets the lowest brightness daylight harvesting can reach.

Why It Matters

  • Prevents the "cave effect" if clouds suddenly block the sun
  • Ensures some electric light is always present
  • Provides a safety margin for sudden daylight changes

Relationship to Trim

If you set minimum dim level lower than low-end trim, the low-end trim value takes precedence as the actual minimum.

Strategy Selection Guide

Space Type Recommended Strategy
Executive office Soft
Private office Soft
Reception area Soft
Open office Mild
Classroom Mild
Meeting room Mild
Retail floor Mild
Storage room Aggressive
Warehouse Aggressive
Loading dock Aggressive
Utility area Aggressive

When to Disable Daylight Harvesting

Disable daylight harvesting in the following situations:

  • No photosensor: Fixtures without photosensors will dim erratically
  • Windowless spaces: No natural light to harvest
  • Consistent lighting required: Spaces where light level must not vary
  • Sensor-ready controllers without connected sensors: Will malfunction

Calibration

For best results, run auto calibration after enabling daylight harvesting:

  1. Navigate to More → Auto Calibration
  2. Select the group to calibrate
  3. Follow the calibration process

Calibration helps the system accurately measure ambient light and set appropriate working levels.

Troubleshooting

Issue Possible Cause Solution
Lights dim erratically No photosensor connected Disable daylight harvesting
Lights too dim in morning Min dim set too low Increase DH Min Dim
Lights don't dim in bright sun Not calibrated Run auto calibration
Rapid flickering Delay time too short Increase delay time
Noticeable stepping Speed too fast Increase speed value

Quick Reference

Strategy Response Min Dim Best For
Soft Slow 50% Private offices, reception
Mild Medium 30% Open offices, classrooms
Aggressive Quick Low-end trim Utility, warehouse
Custom Variable Variable Special requirements

Based on Keilton+autani App User Guide v9.7