The Floor is Lava: Guide to Korean Floor Heating (Ondol)

In Ohio, winter means dry air blowing from vents and cold feet. You wear socks to bed. In Korea, winter means your floor turns into a giant heating pad.

It is called Ondol. It is the greatest heating invention in human history. Hot water pipes run underneath the floor, making the entire room toasty warm. It is why Koreans take off their shoes indoors.

But be warned. If you treat an Ondol floor like a normal floor, you will pay the price. I destroyed $50 worth of cosmetics to learn this lesson.

Welcome to Level 1. Let me tell you about the time I cooked my own handbag.

The Facepalm Files: The Melted Lipstick

Flashback: 3 years ago. My first winter in Seoul.

I came home from shopping. It was freezing outside, so I cranked up the thermostat dial to 30°C (86°F). I was tired, so I dumped my shopping bags on the floor and went to take a shower.

An hour later, I opened my bag. My new chocolate bar felt like a squishy sponge. Worse, my favorite MAC lipstick had turned into red soup. It leaked all over my bag.

I touched the floor. It was burning hot. I realized then: The floor is not a shelf. The floor is a slow cooker.

Enter “Ssam” (The Boiler Engineer)

I called Ssam (my mentor), crying over my ruined bag. “Ssam, my apartment is trying to cook me! Why is the floor so hot?”

Ssam laughed. “Alice, you set the boiler to Sauna mode.”

He explained the Science of Ondol: “Heat rises. By heating the floor, the whole room stays warm without dry air. But you must respect the floor. It is alive.”

Level 3 Wisdom: How to Tame the Beast

Ondol is amazing, but it can be dangerous for your belongings (and your gas bill). Here are the rules.

1. The “No-Melt” Zone

Never place these items directly on the floor in winter:

Cosmetics: Lipstick, creams, lotions (they will separate).
Food: Chocolate, fruits (they will rot faster), kimchi.
Electronics: Laptops or phones (they can overheat).
Solution: Put them on a table, a shelf, or a chair. Raise them up!

2. The “Dried Squid” Warning

Sleeping on the warm floor (Yo mattress) feels amazing. It’s like a hug. BUT, if you sleep there all night with the heat on high, you will wake up dehydrated. Your throat will be dry, and your skin will be crispy. We call this feeling “Dried Squid” (Mareun-ojingeo).

Tip: Keep a glass of water by your bed (but not on the floor).

3. The Money Saver: “Oechul” (Going Out) Mode

Look at your boiler control panel on the wall. Find the button that says 외출 (Oe-chul).

What it is: “Going Out” mode.
When to use it: When you leave the house.
Why: It keeps the water just warm enough so pipes don’t freeze, but it doesn’t heat the room. If you turn the boiler OFF completely, reheating the cold water later costs more gas.

Alice’s Bottom Line: Take Off Your Socks

The best feeling in the world is coming home from a snowy Seoul day, taking off your boots and socks, and stepping onto a toasty Ondol floor. It melts your stress away.

Just remember: Enjoy the heat, but don’t let it melt your lipstick.

Survival Hangul: Boiler Control

“보일러 어떻게 켜요? (Boiler eotteoke kyeoyo?)”
- Meaning: “How do I turn on the boiler?” (Ask your landlord this on Day 1).
“난방 (Nan-bang)”
- Meaning: “Heating” (Look for this button).
“온수 (On-su)”
- Meaning: “Hot Water” (You usually need to press this specific button to get hot shower water).

Read This Next (Before You Make Another Mistake)

Your house is warm? Good. Now let’s fix your social life.