Ultimate Guide to Controlling Glare in Landscape Garden Lighting

Glare is an enduring topic in lighting. As long as there are light sources, glare will persist.

So, how can we reduce glare in night landscape lighting?

As a professional outdoor lighting manufacturer, ADNLITE is here to answer this question for you.

Causes of Lighting Glare

Glare arises under specific conditions within our visual field. It occurs when there is extremely high brightness or when the contrast in brightness is significant. These conditions can impair visual function and cause discomfort to the eyes.

To control glare, it is essential to reduce the extreme brightness and minimize the contrast in brightness across the visual field. One primary cause of high brightness levels is directly looking at light sources. When the brightness ratio reaches 20:1, it can make the eyes uncomfortable and lead to glare.

At night, the natural environment is inherently dark; for example, a full moon provides only 0.22 lux on the ground. When landscape lighting is activated, the illuminance can surge to dozens or even hundreds of lux, which generates glare.

Creating a Glare Control Distribution Diagram

Glare Control Distribution Diagram

To address glare effectively, it is crucial to study the distribution of high-rise buildings, vehicular movement paths, and pedestrian pathways. The goal is to create diagrams that include high-rise building glare control, vehicular movement control, and pedestrian movement control.

Minimizing directly visible light sources

One key measure to reduce glare is minimizing directly visible light sources. Here are some strategies:

Lowering the Beam Angle of Street and Garden Lights

Landscape Light Posts as a Source of Glare

Short Column Lights Emitting Light from the Top

Short Column Lights Emitting Light from the Top

Excessive and Bright In-ground Lights

Excessive and Bright In-ground Lights

Specific Measures to Reduce Glare:

  • Using Cut-off Luminaires for Precision Lighting Control
    • These fixtures are designed to precisely control where the light is cast, significantly reducing glare.
Using Cut-off Luminaires for Precision Lighting Control
  • Using Reflective Type Luminaires
    • These fixtures do not direct light downwards, which helps in minimizing glare.
Using Reflective Type Luminaires
  • Employing Strictly Controlled Low-level Luminaires
    • Low-positioned lights help reduce glare as they keep the light directed more towards the ground.
Employing Strictly Controlled Low-level Luminaires
  • Limiting the Size and Brightness of In-ground Lights
    • By restricting these parameters, glare can be further reduced.
Limiting the Size and Brightness of In-ground Lights

Control Glare from tree lighting

For a detailed look at measures to control glare from tree lights, click here.

Controlling Glare for In-ground Lights, Floodlights, and Wall Washers

Before positioning lighting fixtures, it is essential to consult the residential glare control diagram and the roadway glare control diagram. Based on the proximity of the light to the human eye, appropriate glare control measures should be taken.

In-ground Lights:

  • Install grilles to reduce wide-area high brightness glare or use polarizing filters to minimize direct light exposure.
In-ground Lights

Floodlights and Wall Washers:

  • While some of these lights come equipped with grilles, more often, they utilize shading covers to control spill light.

Specific Example with Floodlights:

Floodlights and Wall Washers
  • The diagram below shows a floodlight installed along the roadside. None of the anti-glare measures can prevent glare if the light is at eye level. However, mounting the light fixture on a pole above the eye level can prevent the light from shining directly into people’s eyes.
Specific Example with Floodlights

This strategic placement and the use of specific light-controlling accessories ensure that the lighting serves its purpose without causing discomfort or safety hazards due to glare.

Glare Prevention Measures for Guide Lights and In-ground Guide Lights

Guide lights and in-ground guide lights are often installed in the middle of roadways, some for decorative purposes and others for directional guidance. To ensure these lights are effective, they usually need to be quite bright, which can lead to glare issues. Additionally, lights installed in the middle of the road must be durable enough to withstand impacts and heavy pressure.

Given that these fixtures are small and low-cost, traditional glare prevention measures may not be suitable.

What can be done? Here’s an effective solution:

Change the Installation Location
  • Change the Installation Location:
    • Instead of installing the lights in the middle of the road, consider placing them along the sides of the road.
  • Adjust the Lighting Direction:
    • Shift from directing light upwards to laterally illuminating the road surface.

This approach not only significantly reduces glare but also enhances the visibility of the road surface while avoiding damage from vehicle traffic. By adjusting the position and direction of the lights, a practical and aesthetically pleasing lighting effect can be achieved, minimizing glare’s impact on drivers and pedestrians.

High Brightness Ratios in Landscape Lighting and Their Glare Prevention Measures

Overly Bright Sculptures and Water Features
  1. Overly Bright Sculptures and Water Features In landscape settings, lighting is often used excessively to highlight sculptures and fountains, resulting in localized areas of high brightness. This can create an extremely high brightness ratio between the landscape feature and its background, causing glare. After viewing these brightly lit features, it might be difficult to see the surroundings until the eyes adjust. A brightness ratio of around 10:1 is already sufficient to highlight the key lighting areas without excessive brightness.
  2. Inverted Brightness Ratios on Pathways and Along Roadsides If the sides of a path are too bright, it can be difficult for the eyes to focus on the road surface. Regardless of the lighting method used on the sides of the pathway, the road surface itself must have sufficient brightness to balance the brightness ratio. Highly reflective walls along the sides can reflect light onto the pathway surface, increasing its brightness and reducing the brightness ratio.
  3. High Brightness Ratio Between Water Surfaces and Pathways on Water Channels On water channels, the brightness contrast between the water surfaces on either side and the pathway can be too great, leading to discomfort.
  4. Narrow Beam Angles from Short Post Lights Roadside lights with too narrow an opening can create a high brightness ratio on the road surface, resulting in glare.
  5. Overly Bright Lights in Tunnel Bridges Floodlights illuminating tunnel bridges can be too bright and directed at too wide an angle, causing the light to directly hit the eyes of passersby. Adjusting the angle and power of these floodlights can achieve a more comfortable effect.

Call to Action

For professional guidance and solutions on managing glare in your landscape lighting projects, contact ADNLITE. We specialize in optimizing lighting setups to enhance both aesthetics and comfort, ensuring your outdoor spaces are beautifully illuminated without the discomfort of glare. For more details, visit us at ADNLITE. Our team is ready to assist you in achieving the perfect lighting environment for your needs.