Lighting Grids & Room Lux Mapping

A lighting grid divides a room into a structured layout of cells, allowing you to record measured lux values at each point. This creates a complete map of light distribution across the space.

Benefits of using lighting grids:

• Visualise where illuminance is high, low, or meets target levels
• Identify dark spots that need additional fittings
• Document compliance with lighting standards (e.g., 500 lux for offices)
• Generate professional heat map reports for clients
• Plan new installations with data-driven decisions

Each cell in the grid typically represents 1 square metre. Match your grid dimensions to your room size:

• Small office (4m × 5m): Use a 4×5 grid
• Meeting room (6m × 8m): Use a 6×8 grid
• Warehouse (20m × 30m): Use a 20×30 grid or sample at 2m intervals with a 10×15 grid
• Corridor: Use a long narrow grid like 2×10 or 1×15

You can add or remove rows and columns at any time, so start with your best estimate and adjust as needed.

Recording lux values is simple and intuitive:

• Tap any cell in the Room Grid View to open the input screen
• Position your phone at that location in the room (typically at desk height or 0.85m from floor)
• Take a lux reading using the main lux meter function
• Enter the value in the cell input field
• Add a light reference (optional) to note nearby fittings
• Tap Save to store the measurement

Pro tip: Long-press a cell to clear it if you entered the wrong value.

Total lux is the sum of all lux values recorded across the entire grid. It gives you an overall measure of the light output in the space.

Average lux is the total divided by the number of cells with values, giving you the mean illuminance level for the room.

Why average lux matters:

• Compare against required standards (e.g., 500 lux for offices, 300 lux for general areas)
• Identify if the overall lighting meets design specifications
• Demonstrate compliance to clients and auditors
• Plan whether additional fittings are needed

Yes! Tap the PDF export button in the Room Grid View to generate a professional heat map report. The PDF includes:

• Visual grid layout with all lux values
• Colour-coded heat map showing light distribution
• Total and average lux statistics
• Job reference and client address
• Survey date and time
• Your contractor logo and contact details

PDFs are perfect for client presentations, compliance records, and project documentation.

Absolutely! Lighting grids are excellent for documenting emergency lighting illuminance. Here's how:

• Create a grid for each escape route or open area
• Switch the building to emergency lighting mode
• Record lux levels at each grid point along escape routes
• Verify minimum levels: 1 lux on escape routes, 0.5 lux in open areas (BS 5266-1)
• Export the PDF as evidence for fire risk assessments

The grid documentation provides clear visual proof of compliance for auditors and enforcing authorities.

Lux Meter Pro offers two visual styles for grid cells:

• Square cells: Traditional spreadsheet appearance, good for precise layouts and technical documentation
• Circle cells: Cleaner heat map look, better for client presentations and visual impact

Both display exactly the same data - choose the style that works best for your reports and client preferences. You can switch between them at any time without losing data.

Correcting values is easy:

• To edit: Tap the cell, enter the new correct value, and save
• To clear: Long-press the cell to remove the measurement completely
• To see better: Pinch to zoom the grid for easier selection of specific cells

All changes are saved automatically to your grid's CSV file, so you never lose your work.

Your lighting grid data is stored securely on your device:

• Grid metadata (job reference, address, dates) saved in grids.json
• Lux values for each grid saved in individual gridId.csv files
• Cloud sync available with Professional subscription for backup and multi-device access

You can return to any saved grid at any time, add more measurements, regenerate PDFs, or continue a survey you started earlier.

The basic lighting grid feature is included in Lux Meter Pro. Here's what's available:

• Free tier: Create grids, record lux values, view totals and averages
• Professional subscription: Unlimited grids, PDF export with your branding, cloud sync, priority support

Lux Meter Pro is rated 4.9 out of 5 stars by 199 professionals. Try the grid feature today and see how it transforms your lighting surveys!