TILLUME lighting pre-planning tool

24V LED Spot Planner

Estimate how many 24V LED spots a room may need by combining target lux, lumen demand, beam angle, mounting height, spot spacing, power supply size and basic controller notes.

Input

Use realistic dimensions and the actual spot beam angle from the product data sheet.

Room and target lux

Room dimensions

Room dimensions - top and side view

Spot and system data

Result

The main result is a practical residential recommendation. A conservative reserve check is shown separately below.

How to read this result: The target lux is used as a minimum planning threshold. The final estimated lux at 100% output may be higher because the spot count is rounded up and the layout also checks beam-angle-based spacing. In DALI, KNX, Loxone or PWM systems, daily brightness can usually be reduced by dimming.
9Practical recommendation
3 x 3Suggested grid
96 WMinimum PSU class

Spot layout

Calculated grid - top view with dimensions
Brightness check
Spacing check
24V system check

Planning values

Dimming scenario preview

Note: Estimated lux values are simplified linear lumen estimates. Actual perceived brightness depends on the dimming curve, controller settings, PWM behaviour, room surfaces and human visual adaptation. 1% is a reference for very low-level scenes and depends on the selected controller, PWM frequency and parameters.

System notes

Cable length and voltage drop: After choosing the spot quantity and power supply size, check cable length and voltage drop with the dedicated calculator. Open voltage drop calculator
Important: This calculator provides a practical pre-planning estimate for 24V LED spot systems. It does not replace professional lighting design according to DIN EN 12464-1. For workplaces and norm-critical projects, photometric data, UGR, maintenance factor, room reflectance and uniformity must be checked separately.

How to use the TILLUME 24V LED Spot Planner

This planner estimates the number of TILLUME 24V LED Spot modules, approximate illuminance, beam coverage, layout spacing, and 24V power load for a room. Use it for early layout comparison before detailed lighting design and site verification.

The result is a planning reference, not a final lighting certificate. Room geometry, surface reflectance, luminaire housing, and controller behaviour must still be checked for the project.

1

Input Guide

01

Room dimensions

Enter the usable room length and width in metres. For L-shaped rooms, galleries, sloped ceilings, or strongly divided zones, calculate each practical lighting zone separately.

02

Ceiling and working-plane height

The planner uses the difference between ceiling height and working-plane height to estimate beam diameter at the useful plane. For desks or kitchen worktops, the working plane is usually higher than the floor; for corridors it may be close to floor level.

Common working-plane heights
Kitchen worktop 0.90-0.92 m Typical UK/US residential kitchen reference; US kitchens often use 36 in / about 0.91 m.
Dining table 0.74-0.76 m Use for dining areas or multifunction tables.
Desk / home office 0.72-0.75 m Use for desks, study rooms and home-office work surfaces.
Coffee table / low task area 0.40-0.45 m Use only when the visual task is close to a low table.
Corridor / circulation 0.00-0.20 m Use floor level or a low plane when no working surface is relevant.
03

Target illuminance

Enter the target lux for the room task. The calculated full-output lux may be higher than the target because the number of Spots is rounded up and spacing is checked against practical layout limits.

04

Surface brightness

Use 0.70 for mostly light, matte rooms such as white plaster, light painted walls, pale wood or light tile floors. Use 0.60 for mixed interiors with medium wood, coloured walls, grey floors or some dark furniture. Use 0.50 for dark walls, dark wood, concrete, black ceilings or large dark furniture areas.

05

Spot type and output mode

Select the TILLUME 24V LED Spot module used in the project. Beam angle, lumen value, and wattage are loaded automatically. For SKU 81061M04, use Wattage balance mode for normal two-channel planning and Max brightness mode only when the controller configuration supports that operating mode.

06

Utilisation and maintenance factors

These factors keep the calculation conservative. Utilisation factor accounts for room geometry and surface reflectance. Maintenance factor accounts for light reduction over time from ageing, dust, and real installation conditions.

2

Result Guide

Recommended number of Spots

The number is rounded upward to meet the selected target illuminance and then checked against approximate spacing logic.

Estimated lux at dimming levels

The preview shows approximate illuminance at 100%, 50%, 20%, 10%, and 1% output. Real low-end dimming depends on the PWM controller, DALI/KNX actuator, parameters, and load behaviour.

Spot layout

The layout diagram distributes Spots evenly across the room and shows approximate dimensions. Use it as a starting point before checking furniture, ceiling cut-outs, joists, beams, and luminaire housings.

24V power load

The planner estimates LED load and recommended power-supply capacity with reserve. Check voltage drop separately for the final cable route.

3

Calculation Method

1

Required maintained lumens

Lumens = Area × target lux / (UF × MF)

2

Spot quantity

Number of Spots = ceiling(required lumens / lumens per Spot)

3

Beam diameter

Beam diameter = 2 × mounting height × tan(beam angle / 2)

4

Power supply planning

Recommended PSU = total LED wattage × 1.20

A 20% reserve is a practical planning value for 24V power supplies.

!

Important Limitations

  • Use the planner for preliminary room and product comparison only.
  • Confirm the final layout with room geometry, surface colours, ceiling construction, and the selected luminaire housing.
  • Check wiring, voltage drop, controller channel load, and power-supply position separately.
  • For DALI, KNX, Loxone, or other smart-home systems, confirm that the final controller provides a suitable 24V PWM output.
  • Final installation and electrical design must be verified by a qualified professional.

TILLUME 24V LED Spot Planner — Version 1.0 — June 2026