Difference Between High Bay-Low Bay and Flood Light Fixture


  • In the lighting industry, the term “bay” means to illuminate any large area.
  • High Bay fixtures and Low Bay fixtures are used to for illumination in Buildings with higher ceilings like warehouse lighting, industrial lighting, Commercial lighting, retail lighting, and gym lighting.
  • High Bay Lighting and Low Bay Lighting are mounted at high level via a pendant, chain, or directly to a ceiling or ceiling girder.

Type of Lighting Fixture for Larger Area Illumination:

  • There are three type of lighting fixture to illuminate large open Area
  • Low Bay Lighting Fixtures
  • High Bay Lighting Fixtures
  • Flood Lights

 (1) Low Bay Light Fixture.

  • As the name says, these bay lights are often used with lower ceilings in open areas.
  • Low bay lights are designed to illuminate open areas with ceilings Between 12 foot to 20 foot.
  • Anything use over this height treat as high bays, and anything lower is very uncommon in large open area facilities, and would require a different type of light fixture.
  • The reflectors or lens for low bays also spread the light far out to maintain a desired lighting level.



  • Ware House.
  • Petrol Station.
  • Retail Store.

(2) High Bay Light Fixture.

  • As their name implies, high-bay lights are used to illuminate spaces with high ceilings. That usually means ceilings ranging from 20 feet to 45 feet.
  • These light is effective at high Ceiling Level to provide well distributed and uniform light for open areas.
  • They need specifically reflectors (for HPS / MH bulbs) or lens angles to ensure light reaches the floor evenly and reduces wasted light. Different kinds of reflectors can accomplish different kinds of illumination tasks for high-bay lights. Aluminum reflectors make light from the fixtures flow directly downward to the floor, while prismatic reflectors create a more diffused lighting useful for illuminating shelves and other elevated objects in a space.
  • High-ceiling location has more space to fill, hence a high-bay by definition is a powerful light source that can brighten up a large area.
  • High-bay lighting is provides clear, uniform lighting of what’s below it with little glare.
  • Numerous types of fixtures can be used as a high-bay lights like LED lights, induction lights, metal halide lights, and fluorescent lights.
  • For instance, LED lights offer extremely long life and energy efficiency but require a bigger initial investment, while traditional incandescent lights are less expensive to purchase initially but don’t last as long and use more energy.
  • There are several types of fixtures available for high-bay lights. Round high-bay lights, linear high-bays, architectural high-bays and grid-mount high-bays.



  • Whenever a large indoor space needs to be illuminated, high bay lighting is usually appropriate. These area is typically vast and cover a lot of vertical as well as horizontal space. This need powerful lighting to provide the appropriate Lux levels to adequately illuminate.
  • High bay lighting fixtures typically hang from the ceiling via hooks, chains or pendants, or they may be fixed to the ceiling directly (similar to troffer lights).  
  • Various industries and facilities require high bay lighting. Some of the most common are
  • Industrial facilities.
  • Manufacturing facilities.
  • School and university gymnasiums.
  • Municipal facilities like community centers or recreation centers.
  • Commercial applications like department stores.
  • Airport hangar or any large open area industrial and commercial space with relatively high ceilings

Choosing the Correct High Bay & Low Bay Fixture

  • Choosing the right High Bay fixture can make the difference between a successful lighting project or
  • A light designed for a warehouse is a totally different than a light designed for a gymnasium or a factory floor. In gymnasium or a factory floor, a light can distribute in the area evenly while in a warehouse, a light can light up the face of the shelves and on the path way between two shelves.

(A) Lumen Output of Lamps:

  • We cannot be assumed that 100% of the lamp output will be emitted from the fitting or that the light output will be constant over its operational lifetime.
  • The actual total illumination levels that can be provided by an installed commercial light fitting will depend on the Light Output Ratio:
  • As an example, an industrial or warehouse high bay light fitting with a LOR of 70%, this indicates that 30% of the lamp’s light output is lost due to the design of the fitting.
  • The light output ratio is need to be consider in commercial lighting installation because when a lamp is positioned in a light fitting (such as an industrial 400W metal halide high bay) losses of light occur within the fitting itself.

(B) Beam Angle:

  • For maximum light coverage, we need to select a beam configuration that matches the height of the high bay light.


  • The common beam angles used for high-bay lighting are 60°, 90° and 120°.
  • The narrow beam angle creates a more focused beam enabling a high lux level on the floor or the platform.
  • The wider beam angle ensures large open areas with lower roof heights receive an excellent spread of light.


Beam Angle

Beam Angle

Ceiling Height


Up to 4 meter


4 to 6 meter


6 to 8 meter


8 to12 meter


Beam Angle & Applications

Beam Angle



Spot Lights Stadium Lights


Spot Lights Stadium Lights


Residential and Architectural Lighting


Commercial and Industrial Lighting


Commercial and Industrial Lighting


Low Ceiling Gas Stations and Public Spaces


Industrial Lighting Parking Garages


Beam Angle & Fitting Type

Beam Angle

Type of Fitting

4° To 9°

Spot Light

20° To 35°

Flood Light

36° To 49°

Wide Flood Light

More than 60°

Very Wide Flood Light

(C) Glare:

  • When there is an excessive contrast between the dark areas and bright areas in the direction of viewing, then glare can occur. When there is too much light, it will cause glare.
  • Glare can happen during daytime and nighttime. Examples of where glare can occur includes moving from a shaded location into bright sunlight, and the reflection of light from a surface which is shiny.


(D) Fixtures Shape

  • Circular fixtures creates circular beams; rectangular fixtures creates rectangular beams.
  • Round LED high bays certainly have their universal application, but if we are going to illuminate a long workbenches or a production line, we may get more efficient results from a rectangular linear high bay

(3) Flood Light Fixture.

  • A floodlight is called Flood Light because it illuminate evenly a large area with high intensity of Light.
  • Flood lights are a general method for illuminating areas where a conventional mounting arrangement of Fixtures may or may not be an available and we can also change direction Light or tilt Angle.


  • The flood light have an asymmetric throw of light which can be angled into the space to be illuminate.
  • Flood light illuminate uniformly in all directions and its exposure range can be adjusted.
  • Flood Lights utilizing light bulbs of high power to illuminate a big outdoor location.
  • Flood light is able to equably shine in all directions. Besides, the shine angels could change freely and is able to generate shadow. It is most widely used to illuminate the whole area.
  • When we install floodlights, we should need to care about glare because the brightness of the fitting is high and it angled close to horizontal.
  • Flood Light is different from spot light. Its light beam is highly diffuse without direction. Therefore, its shadow is gentle and transparency.


  • Floodlights are broad beamed, high intensity lights often used to illuminate outdoor playing fields while an outdoor sports event.
  • Flood light is a good choice for lighting and decoration of construction sites, squares, parks, arts venues.
  • Flood light also use as a object Lighting.
  • Factory buildings, stadiums, golf courses, shops, hotels, subway stations, gas stations, buildings.
  • Sculptures and other indoor and outdoor applications.

Difference between High Bay and Low Bay Lighting.

  • Normally, there is a confusion between high bay light and low bay light because both looks like same and having same applications except installation height and intensity of illumination and lumen output.
  • High bay and low bay fixtures both are typically suspension mounted using chains or hooks, but they may also have the option of being surface mounted depending on the fixture.
  • Actually both are not same lights. There are some differences between them.
  • The wattage
  • The wattage or applications of both are different. The wattage and application determines whether to call them high bay or low bay.
  • If the wattage used is above 100 Watts then it is called  high bay. Those using below 100 Watts are called low bay fixtures.
  • The Mounting Height
  • The  low bay light fixtures are used in areas where the bottom of the fixture is up to 20 feet or less above the floor.
  • They are usually spread the light evenly. They also contain optical refractors which cover the lamp thereby reducing glare. Their widespread distribution improves the vertical illumination and also permits spacing as much as 2 or more times the mounting height.
  • High bay lighting fixtures, they are mostly used in areas where the bottom of the fixture is 20 feet or more above the floor.
  • They allowing for a more concentrated beam spreading with a prominent downward component. High wattage is needed so as to illuminate the space properly.


Spacing between lights



15 feet

12 feet to 15 feet
20 feet

15 feet to 18 feet

30 feet

20 feet to 25 feet


Height and lumens


10 to 15 feet

 10,000 to 15,000 lumens

15 to 20 feet

16,000 to 20,000 lumens
25 to 30 feet

 33,000 lumens


Low Bay / High Bay Lighting Fixtures


Installation height Distance Fixture To Fixture
50 Watt 3 Meter

3 To 6 Meter

90 Watt

4 Meter 6 Meter

120 To 150 Watt

5 Meter 6 To 8 Meter
200 Watt 7 Meter

9 To 10 Meter

300 Watt 8 Meter

More than 10 Meter

Difference between Spot Light and Flood Light.

  • A spotlight casts a narrow beam of light, usually no wider than 45°. This beam is more concentrated and easier to point and control.
  • A floodlight can have a beam spread of up to 120°. It can illuminate a larger amount of space with the same wattage and lumen output as a spotlight.
  • Flood Lights is generally utilized for highlighting the architectural appearance of an outstanding or historically Building.
  • By utilizing flood lights, we can boost the in-depth framework of a building.

Determining beam width:

  • The width of a light’s beam in degrees is not always helpful. It should be much easier to know the beam width in feet, from a given distance away.
  • There is a simple formula to know Beam width
  • Beam Width =Angle of Beam x 0.018 x Distance from Light Bulb
  • If we have an 80 degree floodlight, and we want to know how wide the beam will be from 10 feet away.
  • Beam Width = 80 degrees x 0.018 x 10 feet = 14.4 feet wide

LED Vs Metal Halide

LED Watt

Metal Halide Watt
20W to 50W


30W to 75W

40W to 125W


50W to 175W


60W to 225W


80W to 250W


100W to 350W


120W to 400W

150W to 500W



About Jignesh.Parmar (B.E,Mtech,MIE,FIE,CEng)
Jignesh Parmar has completed M.Tech (Power System Control), B.E(Electrical). He is member of Institution of Engineers (MIE) and CEng,India. Membership No:M-1473586.He has more than 16 years experience in Transmission -Distribution-Electrical Energy theft detection-Electrical Maintenance-Electrical Projects (Planning-Designing-Technical Review-coordination -Execution). He is Presently associate with one of the leading business group as a Deputy Manager at Ahmedabad,India. He has published numbers of Technical Articles in “Electrical Mirror”, “Electrical India”, “Lighting India”,”Smart Energy”, “Industrial Electrix”(Australian Power Publications) Magazines. He is Freelancer Programmer of Advance Excel and design useful Excel base Electrical Programs as per IS, NEC, IEC,IEEE codes. He is Technical Blogger and Familiar with English, Hindi, Gujarati, French languages. He wants to Share his experience & Knowledge and help technical enthusiasts to find suitable solutions and updating themselves on various Engineering Topics.

6 Responses to Difference Between High Bay-Low Bay and Flood Light Fixture

  1. KULDEEP says:


  2. Narendra Singh says:


  3. Tojo says:

    We have 105 x 38 feet indoor cricket nets. The height is 20 ft in the middle and 14 ft in the end. Please suggest whether we shall go for Highbay or floodlight

  4. Steave says:

    Really useful information. Thanks for sharing

  5. Rajendra Chavan says:

    very nice information…

  6. Rajendra Chavan says:

    can i used Flood light 20–70 W in inside industry where machining parts manufactured.

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