16 May and the laser that changed everything

If you’ve ever wondered why the International Day of Light is celebrated on 16 May, the answer lies in one of the most important scientific breakthroughs of the 20th century.

On 16 May 1960, physicist Theodore Maiman successfully operated the world’s first laser. And while a laser may sound like something distant or confined to scientific laboratories, that discovery paved the way for many of the technologies we rely on every day.

Fibre-optic internet, telecommunications, optical readers, certain medical treatments… all of that came later.

That’s why UNESCO chose this date to celebrate the role that light plays in science, innovation, and development.

And while lasers may seem complex, advances in lighting technology have also transformed something much closer to home: our houses. And above all, the way we consume electricity.

The 2026 theme: Light for a Sustainable Future

The theme of the International Day of Light 2026 is ‘Light for a Sustainable Future.’ At its core, it’s about something we are all becoming more mindful of: how to use energy more intelligently.

Years ago, lighting a home meant much higher energy consumption. Light bulbs didn’t last as long, used more electricity, and were far less efficient than the ones we use today.

Today, the situation has changed dramatically.

LED bulbs consume up to 80% less energy than traditional light bulbs and last for many more years. That means lower energy use, fewer bulb replacements, and a smaller environmental impact.

And that is perhaps the most interesting part: sustainability often doesn’t begin with major decisions. It begins with small everyday changes that require almost no effort.

Lighting at home: the 20% of your electricity consumption that’s easiest to reduce

Lighting accounts for around 20% of a household’s total electricity consumption. And even though we don’t always think about it, it is one of the easiest areas to save money.

The best part is that you don’t need to do major renovations or remodel half your home. Sometimes, a few small habits are all it takes. These include:

• Replacing old bulbs with LED ones.
• Turning off lights you don’t actually need.
• Adjusting lighting depending on the room.
• Using sensors or timers.
• Or simply making the most of natural light and switching off artificial lighting when it isn’t needed.

They may seem like small habits, but when repeated every day, they end up making a real difference.

And if you want to go one step further, here you can discover the 15 most effective ways to reduce electricity consumption at home.

LED: the technology that connects the Day of Light with your savings

If one technology perfectly captures everything the International Day of Light celebrates, it’s LED lighting. And not just because it uses less energy.

LED bulbs last longer, generate less heat, and help reduce energy consumption without compromising lighting quality. In fact, in many cases, the opposite happens: the overall lighting quality at home actually improves.

That’s why LED lighting continues to be one of the easiest ways to start saving energy right away. In fact, replacing half of your light bulbs with LEDs can save around €24 per year.

And if you’re still unsure which type of lighting to choose, it may help to understand the difference between incandescent, halogen, and LED bulbs.

Also, if you’re thinking about making the switch at home, here you can see how to replace your household bulbs with LEDs and how much you can save step by step.

Because sometimes saving energy starts with something as simple as changing a light bulb.

Three things you can do today to celebrate the Day of Light in a practical way

You don’t need to make major changes to take part in the International Day of Light. In fact, it’s often the smallest choices that end up having the greatest impact.

1. Replace the bulbs in the rooms you use most

The living room, kitchen, or one’s workspace usually account for many hours of lighting every day. Starting with those rooms is often the most cost-effective option.

2. Make better use of natural light

It may sound obvious, but we often use artificial lighting even when we don’t really need it.

Opening the blinds fully, rearranging some furniture, or opting for lighter colours can help you make the most of daylight throughout the day.

3. Lower your screen brightness

Energy efficiency is also about those tiny details we usually overlook.

Reducing screen brightness can help you cut down on energy consumption almost without you noticing.

Because using energy more efficiently doesn’t mean living less comfortably. Very often, it simply means paying a little more attention to how we use energy every day.

FAQ

Why is the International Day of Light held on 16 May?

This date was chosen because on 16 May 1960, Theodore Maiman successfully operated the world’s first laser. UNESCO used this milestone as the basis for this celebration to remind us how vital light is to everything, from science to sustainable development.

What Is the theme of the International Day of Light 2026?

The theme of the International Day of Light 2026 is ‘Light for a Sustainable Future,’ focusing on energy efficiency, innovation, and responsible energy consumption. The goal is to remind us that technology can also help us consume less and more efficiently, even in everyday actions as simple as lighting our homes.

How much can I save by replacing all my bulbs with LEDs?

There isn’t an exact figure because it depends on each household, but LED bulbs can use up to 80% less energy than traditional ones. The good thing is that you don’t have to replace them all at once, since even switching them gradually can make a noticeable difference on your electricity bill.

What percentage of a home’s electricity consumption goes to lighting?

On average, lighting accounts for around 20% of a household’s total electricity consumption. While this can vary depending on the size of the house and usage habits, it’s one of those areas where small changes can have a significant impact.