No Radiators, No Vents: Seeing the Secret of 'Ondol' with a Thermal Camera

 Looking beneath the floor of my apartment and planning for my apiary.

In the Korean winter, there is a reason why homes feel uniquely cozy. It’s not because of the warm air—it’s because the floor itself is warm.

We take this for granted in Korea, but I know that globally, our heating system, called 'Ondol,' is quite unique.

Today, I decided to use a thermal imaging camera to look beneath the surface of my apartment floor. I also want to share how this technology is influencing my plans for a future resting hut at my apiary.

1. The Anatomy of Warmth: How Ondol Works

When you step onto a warm Korean floor, you are standing on top of a sophisticated engineering system. This AI-generated image illustrates exactly what is happening beneath our feet.

Unlike Western homes that often use radiators to heat the air, our system starts with a boiler. It heats water and pumps it through a complex network of pipes—known as "XL pipes"—embedded in the concrete floor.

Think of it as a giant, invisible radiator lying flat under the entire room. This structural design is the true identity of the warmth we feel.

2. The Controller: A Modern Fire Pit

In the old days, our ancestors fed wood into a fire pit (Agungi) to heat stones under the floor. Today, we just press a button on this small controller on the wall.

As a former IT manager turned farmer, this device looks familiar to me. It reminds me of the temperature controllers in a server room! It acts as the commander, firing up the boiler and sending hot water rushing beneath our feet whenever the temperature drops.

3. Seeing the Invisible (Thermal Camera Reveal)

I couldn't rip up my apartment floor to show you how it works, so I used technology instead. I took a shot with my entry-level thermal camera.

Although the image is a bit rough, you can clearly see the red and yellow lines.

These are the "XL Pipes" (hot water heating coils). Like blood vessels in a body, they circulate hot water throughout the house, heating the concrete floor slab.

This is called a "Wet System." We lay the pipes and pour wet cement over them. Once the concrete heats up, it holds the heat for a long time (thermal mass). The glowing red lines in the photo are proof of that stored energy.

4. Evolution of Ondol: My Plans for the Apiary

But did you know that Ondol is evolving?

While my apartment uses the traditional "Wet System" (pipes in concrete), a new trend called the "Dry System" is rising fast.

Instead of pouring heavy cement, the "Dry System" fits pipes into pre-made modular panels. It’s easier to install and, most importantly, it heats up much faster.

This brings me to my current dilemma as a beekeeper.

I am planning to build a small resting hut (farm stay) at my apiary in Gokseong. For that space, I'm considering the "Dry System" instead of the heavy "Wet System" used in apartments.

Why? Because when I'm working with the bees in winter, I need the floor to get warm immediately when I step inside for a break. I don't need it to stay warm for 24 hours like a house; I need speed and efficiency.

5. Conclusion

What we saw today with the thermal camera is the "Ondol of the Present" (Wet System). What I hope to experience at my farm in the future is the "Ondol of the Future" (Dry System).

The principle remains the same: The floor must be warm. But the technology keeps moving forward.

When I eventually build that hut at the apiary, I promise to come back with a real installation review of the "Dry Ondol" system. Until then, I will gratefully endure this winter on the warm floors of my apartment.