Shielded lights focus illumination for plants and paths. Enter fixture lumens, area, height, and losses. Get fixture count, predicted lux, and glare reduction guidance.
| Scenario | Area (m) | Target (lux) | Fixture lumens | Shield % | CU | LLF | Required fixtures |
|---|---|---|---|---|---|---|---|
| Path border lighting | 6 × 4 | 15 | 800 | 85 | 0.60 | 0.80 | Ceil((15×24)/(800×0.85×0.60×0.80)) = 2 |
| Seating corner | 4 × 4 | 30 | 600 | 90 | 0.55 | 0.75 | Ceil((30×16)/(600×0.90×0.55×0.75)) = 3 |
| Wide planting bed | 10 × 3 | 10 | 1000 | 80 | 0.65 | 0.85 | Ceil((10×30)/(1000×0.80×0.65×0.85)) = 1 |
1) Area
A = L × W
2) Shielded lumens
Lm_shielded = Lm_fixture × (Shield% ÷ 100)
3) Delivered lumens per fixture
Lm_delivered = Lm_shielded × CU × LLF
4) Required fixture count
N_required = (E_target × A) ÷ Lm_delivered
Rounded planning count: N_rounded = ceil(N_required)
5) Predicted average illuminance for your chosen fixture count
E_avg = (N × Lm_delivered) ÷ A
6) One-point estimate at target center (simple reference)
Distance: d = √(h² + offset²)
E_center ≈ Lm_delivered ÷ (4πd²)
Notes: CU and LLF simplify real-world behavior. For critical layouts, validate with manufacturer photometrics, aiming angles, and on-site measurements.
Shielded luminaires direct most output downward, reducing glare and spill. In gardens, this improves visual comfort on paths, protects neighboring windows, and limits insects circling bright sources. It also preserves dark adaptation, so plants and textures stay readable. A higher shielding percentage increases useful light per fixture and strengthens night‑sky stewardship.
Illuminance should match the activity and risk. Simple wayfinding often performs well around 5–20 lux, while steps, seating, or tool areas may need 20–50 lux. Very bright scenes can feel harsh in greenery and waste energy. Higher targets raise fixture count and load. Use the predicted lux to compare scenarios before buying, and keep color temperature modest for comfort.
Coefficient of utilization represents how well light lands on the intended area after aiming and distribution. Light loss factor captures dirt, aging, lens yellowing, and voltage effects. When conditions are dusty, coastal, or irrigation is frequent, choose a lower LLF. Conservative factors prevent under‑lighting after months of use. If you have fixture photometrics, adjust CU based on beam spread and aiming angle.
Spacing influences uniformity more than raw lumen totals. The calculator estimates average spacing from area and fixture count, then provides a maximum spacing guideline based on mounting height. If spacing exceeds the guideline, add fixtures or raise mounting height carefully to avoid hot spots and shadows. For path edges, stagger fixtures to smooth brightness transitions. Validate with a simple lux meter at midpoints and corners.
Use the rounded required fixture count as a planning baseline, then test with temporary placement at night. The connected load estimate helps size transformers, drivers, and circuits, and the efficacy figure supports product comparisons. Exporting CSV or PDF keeps a clear record for clients, crews, and maintenance plans. Record fixture model, shielding rating, and aiming notes alongside results. This documentation simplifies future expansions and troubleshooting over time.
It estimates the percentage of lumens directed downward into useful light. Higher values usually reduce glare and spill, but actual performance still depends on aiming, mounting height, and the fixture’s optical design.
Start with 0.50–0.70 for typical garden layouts. Use the lower end for narrow beams or poor aiming. Use the higher end for well‑aimed wide distributions covering the area evenly.
Lighting design must meet the target even with losses and unevenness. Rounding up provides a practical purchasing quantity, then you can dim, re‑aim, or space fixtures to refine the final look.
No. It is a simplified reference using distance and delivered lumens. Real results vary with beam angle, shielding geometry, reflections, and obstructions. Measure on site when accuracy matters.
Plants do not require lux at night for growth. Use lighting for people: safe walking, focal points, and task zones. Keep levels modest to reduce disruption to wildlife and neighbors.
Increase shielding, lower output per fixture, and aim away from eye lines. Use lower mounting heights, add louvers, or choose wider distributions for smoother brightness. Avoid exposing bright sources directly to viewpoints.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.