Lighting Q&A: how many high bay lights do i need

At PacLights, we often hear the question: “How many high bay lights do I need?” It’s a crucial consideration for anyone planning to illuminate large, open spaces effectively.

The answer depends on several factors, including ceiling height, room dimensions, and the specific lighting requirements of your space.

In this post, we’ll break down these factors and provide practical guidance to help you determine the right number of high bay lights for your project.

What Affects High Bay Lighting Needs?

Ceiling Height and Space Dimensions

The height of your ceiling is a primary consideration when planning high bay lighting. Higher ceilings require more powerful lights or a greater number of fixtures to achieve adequate illumination at ground level. A space with a 30-foot ceiling typically needs more lumens than one with a 20-foot ceiling.

Room size also plays a key role. A larger floor area naturally requires more fixtures to maintain consistent light levels throughout the space. The shape of the room matters too – long, narrow spaces might benefit from linear high bays, while square rooms might work better with UFO-style fixtures.

Light Intensity for Specific Tasks

Different activities demand varying levels of illumination. A warehouse used primarily for storage might require less intense lighting (around 10-20 foot-candles) compared to a manufacturing area where detailed work is performed (30-50 foot-candles or more).

The Illuminating Engineering Society (IES) provides specific recommendations for light levels in various industrial and commercial settings. These guidelines serve as an excellent starting point for determining your lighting needs.

Surface Reflectivity

The colors and materials of your walls, floors, and ceiling significantly impact lighting efficiency. Light-colored, reflective surfaces bounce more light around the space, potentially reducing the number of fixtures needed. Dark or matte surfaces absorb more light, often requiring additional fixtures to achieve the same illumination level.

A space with white walls and a light-colored concrete floor might need 20% fewer fixtures than a similar area with dark walls and flooring.

Fixture Specifications

The type and wattage of high bay lights you choose directly affect the quantity needed. LED high bays are typically more efficient than traditional metal halide fixtures, producing more lumens per watt.

A 150W LED high bay might replace a 400W metal halide fixture while providing similar or better illumination. This efficiency means you might need fewer LED fixtures to light the same area adequately.

Additionally, the beam angle of the chosen fixtures impacts coverage. A wider beam angle (like 120 degrees) covers more area but with less intensity, while a narrower beam provides more focused light.

These factors form the foundation for determining the right number of high bay lights for your space. However, complex or unique spaces often benefit from professional lighting design services to ensure optimal results. In the next section, we’ll explore methods to calculate the exact number of high bay lights needed for your specific requirements.

How to Calculate Your High Bay Lighting Needs

Understanding Light Measurements

To determine the number of high bay lights you need, you must first understand two key terms: lumens and foot-candles. Lumens measure the total light output of a fixture, while foot-candles measure light intensity at a specific point. High bay applications typically require 30 to 50 foot-candles for general tasks, and up to 100 foot-candles for detailed work.

To calculate the total lumens needed, multiply your required foot candles by the area in square feet. For instance, a 10,000 square foot warehouse needing 30 foot-candles would require 300,000 lumens (10,000 x 30).

The Room Cavity Ratio Method

For more precise calculations, lighting professionals use the Room Cavity Ratio (RCR) method. This method takes into account the room’s dimensions and reflectance values. The formula is:

RCR = 5 x H x (L + W) / (L x W)

Where H is the mounting height above the work plane, L is room length, and W is room width.

A lower RCR (usually below 2) indicates a space where light distributes more easily, potentially requiring fewer fixtures. Higher RCRs (above 4) suggest a space where light has difficulty reaching all areas, often necessitating more fixtures or higher output lights.

Advanced Lighting Design Tools

For complex spaces or when precision is critical, lighting design software like DIALux or AGi32 provides the most accurate results. These tools create 3D models of your space, factoring in all variables including obstacles, windows, and specific fixture photometrics.

While powerful, these tools often require specialized knowledge. That’s why many facility managers opt for professional lighting design services. Some lighting companies (including PacLights) offer free lighting layout designs to ensure you get the optimal solution for your space.

Professional lighting designers use advanced software and years of experience to create custom lighting plans. They factor in all the variables we’ve discussed, plus industry-specific requirements and energy efficiency goals. This service not only saves you time but also helps avoid costly mistakes in fixture selection and placement.

Real-World Considerations

While calculations provide a solid starting point, real-world factors may influence the final fixture count and placement. These factors include:

1. Specific task areas (which may require higher light levels)
2. Glare considerations (especially important in spaces with computer screens)
3. Future space changes (flexibility for potential layout modifications)
4. Energy efficiency goals (which may impact fixture selection)

Try to account for these factors when planning your high bay lighting setup. A professional lighting designer can help you navigate these considerations and create an optimal lighting plan for your unique space.

In the next section, we’ll explore common high bay lighting scenarios and provide specific recommendations for different types of facilities.

Real-World High Bay Lighting Examples

Warehouses and Distribution Centers

Warehouses require adequate illumination for safe navigation and efficient operations. A typical warehouse needs 20-30 foot-candles at floor level. For a 100,000 square foot warehouse with 30-foot ceilings, you’ll need approximately 2-3 million lumens total.

Many warehouses now opt for LED high bays with motion sensors. These can reduce energy consumption by up to 90% compared to traditional metal halide fixtures. An e-commerce fulfillment center recently replaced 1000W metal halide fixtures with 220W LED high bays, which cut their lighting energy use by 78% while improving visibility.

Manufacturing Facilities and Workshops

Manufacturing areas often need brighter lighting due to the detailed nature of the work. Try to achieve 50-100 foot-candles, depending on the specific tasks. In a 50,000 square foot facility with 25-foot ceilings, you might need 2.5-5 million lumens.

Consider task lighting for specific workstations to supplement general lighting. This approach can reduce the overall number of high bay fixtures needed while still providing intense light where it’s most critical.

An automotive parts manufacturer switched to LED high bays with task-specific lighting. This change reduced their fixture count by 15% while increasing light levels by 20%.

Gymnasiums and Sports Facilities

Sports facility lighting must balance visibility, glare reduction, and energy efficiency. The Illuminating Engineering Society recommends 30-50 foot-candles for recreational play and 75-100 foot-candles for competitive events.

A standard high school gymnasium (approximately 7,000 square feet with 30-foot ceilings) needs about 350,000-700,000 lumens for general use. However, uniformity and glare are important factors to consider. Many facilities now use LED high bays with wide beam angles (120 degrees or more) to ensure even light distribution.

A university recreation center upgraded to LED high bays, which reduced their fixture count from 48 to 36. This improvement increased light levels and achieved a 62% reduction in energy costs.

Retail Spaces with High Ceilings

Retail lighting creates an inviting atmosphere while showcasing products effectively. Try to achieve 50-100 foot-candles in general areas, with higher levels (100-200 foot-candles) for feature displays.

A 20,000 square foot retail space with 20-foot ceilings might need 1-2 million lumens. However, the distribution of these lumens is important. Consider using a mix of high bay fixtures for general lighting and accent lighting for product displays.

A national retail chain revamped their lighting strategy using LED high bays with color-tuning capabilities. This allowed them to adjust light color and intensity throughout the day, which led to a 15% increase in average transaction value and a 40% reduction in energy costs.

These examples provide general guidelines. Every space is unique, and factors like natural light, surface reflectivity, and specific task requirements can significantly impact your lighting needs. For optimal results, work with a lighting design professional or utilize free layout services offered by manufacturers (such as PacLights).

Final Thoughts

Determining the number of high bay lights you need involves multiple factors such as ceiling height, room dimensions, and task requirements. Professional lighting design proves invaluable in navigating these complex variables and optimizing your lighting layout for performance and energy efficiency. PacLights understands the intricacies of high bay lighting and offers expert assistance to answer the question “How many high bay lights do I need?”

Our team of lighting professionals can help you create a precise lighting plan tailored to your specific space and requirements. We offer free lighting layout designs and a comprehensive range of LED high bay fixtures to meet your illumination needs while reducing energy costs. Our solutions include optional features like daylight and motion controls for enhanced customization.

PacLights guides you through the entire process, from initial planning to final installation. We ensure you achieve optimal lighting performance in your facility while prioritizing safety, productivity, and energy efficiency. Contact us today to create a well-lit environment that enhances operations and contributes to the success of your business.