How to Calculate the Wattage Requirements for Your Home Lighting

Proper lighting not only creates visual comfort, but also contributes to energy efficiency and the overall atmosphere of a room. Most people often choose lights based solely on brightness without considering the ideal lighting requirements for the size and function of the room. In fact, each room has different lighting requirements depending on the activities that take place within it.

Therefore, it is important for homeowners, interior designers, and electrical installation technicians to understand how to accurately calculate lighting wattage requirements. Knowing the wattage needed for a room helps avoid using lights that are too bright or too dim, while also optimizing energy savings. This article will help you understand the basics of calculating lighting wattage requirements and how to apply them to various rooms in your home.

Why Is It Important to Calculate Lighting Wattage Requirements?

Calculating light wattage is not just about aesthetics, but also related to comfort, safety, and energy efficiency. Lighting that is too dim can disrupt activities and cause eye strain, while light that is too bright can cause glare and energy waste. Understanding how much power (watts) is needed allows you to determine the most appropriate number and type of lights.

Formula for Calculating Light Power Requirements

To calculate the power requirements for lighting in a room, you can use a simple formula:

Total lumens required = Room area (m²) x Lighting level (lux)
Total light power = Total lumens / Lumens per watt (lm/w)

Explanation:

• Lux: Unit of lighting intensity per square meter.
• Lumen: Unit of total light emitted by a light source.
• Lumens per watt: LED light efficiency, typically ranging from 80-100 lm/w depending on the type of light.

The following are standard lighting levels (lux) based on types of residential rooms according to SNI-03-6197-2000:

Sample Calculation of Power Requirements for Each Room

Let's calculate the power requirements for various types of rooms in the house:

1. Terrace

For example, your terrace measures 3 meters x 6 meters = 18 m²

The ideal lighting level is 60 lux.

Using LED lights with an efficiency of 100 lm/w

Total lumens = 18 x 60 = 1,080 lumens
Power requirements = 1,080 / 100 = 10.8 watts

Therefore, you can use one 10-watt LED light or two 5-watt LED lights for more even lighting.

2. Living Room

For example, your living room measures 4 meters x 5 meters = 20 m²

Ideal lighting level: 120 lux

Using LED lights with an efficiency of 100 lm/w

Total lumens = 20 x 120 = 2,400 lumens
Power requirements = 2,400 / 100 = 24 watts

This means you can use two 12-watt LED lights or three 8-watt lights for even lighting.

3. Dining Room

For example, a dining room measuring 3 x 3 meters = 9 m²

Ideal lighting level 120 lux

Using LED lamps with an efficiency of 100 lm/w

Total lumens = 9 x 120 = 1,080 lumens
Power requirements = 1,080 / 100 = 10.8 watts

Then, it is recommended to use one 10-watt LED lamp or two 5-watt LED lamps so that the light can be more evenly distributed.

4. Workspace

For example, your workspace measures 2 x 3 meters = 6 m²

Ideal lighting level 120 lux

Using LED lamps with an efficiency of 100 lm/w

Use LED lights with an efficiency of 100 lm/w

Total lumens = 6 x 120 = 720 lumens
Power requirements = 720 / 100 = 7.2 watts

In this case, you can use one 7-8 watt LED light for your workspace.

5. Bedroom

For example, your bedroom measures 3 x 4 meters = 12 m²

Ideal lighting level 120 lux

Using LED lights with an efficiency of 100 lm/w

Total lumens = 3 x 120 = 360 lumens
Power requirements = 360 / 100 = 3.6 watts

The recommended lighting for a bedroom is 3 watts.

6. Bathroom

For example, a bathroom measuring 2 x 2 meters = 4 m²

Ideal lighting level 150 lux

Use LED lights with an efficiency of 100 lm/w

Total lumens = 4 x 250 = 1,000 lumens
Power requirements = 1,000 / 100 = 10 watts

Therefore, you can use one 10-watt LED light, especially above the mirror or main ceiling.

7. Kitchen

For example, a kitchen measuring 3 x 2 meters = 6 m²

Ideal lighting level 150 lux

Using LED lights with an efficiency of 100 lm/w

Total lumens = 6 x 250 = 1,500 lumens
Power requirements = 1,500 / 100 = 15 watts

If the kitchen requires bright light, you can use two 8-watt LED lights or one 15-watt light.

8. Garage

For example, your garage measures 3 x 5 meters = 15 m²

Ideal lighting level 60 lux

Using LED lights with an efficiency of 100 lm/w

Total lumens = 15 x 60 = 900 lumens
Power requirements = 900 / 100 = 9 watts

Thus, you need to use one 9-10 watt LED light or two 5 watt LED lights for more even lighting in your garage.

More Tips for Lighting Efficiency

• Use LED lights because the energy-efficient and longer lifespan compared to incandescent or CFL bulbs.
• Use light colors according to the needs of the room: warm white for comfort (bedroom), cool white for activities (kitchen/workroom).
• Pay attention to the ceiling height and wall color, as they can affect light distribution.
• Use multiple light sources in large rooms to ensure more even light distribution.

Use High-Quality Cables to Support the Lighting System

In addition to selecting the right lights, reliable electrical installations require safe and standard-compliant cables. Use high-quality electrical cables from Wilson Cables to ensure stable and interference-free power flow. Wilson Cables products are SNI-certified and designed for long-term durability in various conditions.

Conclusion

Calculating the power requirements of lights based on the size and function of the room is an important step in creating efficient and comfortable lighting. Follow these simple steps and understand the appropriate lighting standards to determine the ideal type and number of lights for each room in your home. Don't forget to use high-quality cables, such as those from Wilson Cables, for your electrical installation to ensure that your lighting system functions optimally and safely in the long term.