What are sub-ohm e-cigarettes? How they work, simply explained

You read “sub-ohm” very often on atomizers and coils. In our shop in Freiburg, many adult vapers ask us what exactly it means and whether it suits them. In this guide we explain what lies behind the term, how sub-ohm vaping works and how it differs from classic vaping.

What does sub-ohm mean?

Sub-Ohm means “below one ohm”. This refers to the electrical resistance of the heating coil: if it is below 1.0 Ohm, it is called sub-ohm.

Ohm is the unit of electrical resistance. The lower the resistance of the coil, the more current flows at the same voltage and the more power (watts) is converted into heat. As a result, more liquid is vaporised per inhale.

Is every device with a coil below 1 Ohm a sub-ohm device?

Strictly speaking yes, but in everyday use “sub-ohm” usually means vaping with low resistances and higher power in direct lung inhales . Many pod systems have pods with 0.6 or 0.8 Ohm and are therefore technically below 1 Ohm too, but they are used more for mouth-to-lung or loose lung inhales.

How does sub-ohm vaping work?

Low resistance, higher power, more airflow. The coil is heated more, vaporises more liquid, and an open air intake allows a direct lung inhale.

With a direct lung inhale (DL), you inhale the vapour straight into your lungs without first holding it in your mouth, similar to a deep breath. Sub-ohm atomizers need a wide air intake for this. This differs from the mouth-to-lung inhale (MTL) that many people know from smoking a tobacco cigarette.

What power does a sub-ohm coil need?

That depends on the specific coil. The manufacturer states a power range on the packaging or in the description, which you should stick to. An example: according to the manufacturer, the Vaporesso GTi Dual Mesh Head with 0.4 Ohm is designed for 50 to 60 watts. Too much power can overheat the coil and lead to a burnt taste; too little power results in weak vapour. We explain how to set watts and ohms correctly in the guide How many watts at how many ohms?.

Which devices are suitable for sub-ohm?

Box mods with a sub-ohm tank and powerful pod mods. What matters is adjustable power, a suitable atomizer and a battery that can deliver the required power.

A typical example is the GeekVape Aegis Legend 5 kit with the Z Subohm Tank 5: according to the manufacturer, the mod delivers 5 to 200 watts and requires two external 18650 battery cells. The kit includes Z XM Mesh Coils with 0.2 and 0.4 Ohm for direct lung inhales. Some pod mods also work with replaceable sub-ohm heads, such as the Vaporesso GTX or GTi heads. Further devices and their technical data are shown in the overview of e-cigarettes.

What do you need to watch out for with battery cells?

With box mods with replaceable cells, you should only use intact batteries with undamaged wrapping and follow the manufacturer’s instructions. Damaged cells should no longer be used and should be properly disposed of. Replacement cells can be found in the overview of accessories.

Which liquid suits sub-ohm?

Liquids with a high glycerin (VG) content and usually a lower nicotine strength.

Sub-ohm atomizers vaporise considerably more liquid than mouth-to-lung devices. Thicker liquids with lots of glycerin suit the larger openings in the coils better. Because more vapour is produced per inhale, many sub-ohm vapers choose a lower nicotine strength. The available nicotine strengths and mixing ratios are shown in the overview of 10 ml liquids. We explain more about mixing ratios in the guide Which base for vaping?.

What speaks for and against sub-ohm?

More vapour and flavour on the one hand; more liquid and battery consumption and more technology on the other.

• Vapour and flavour: The higher power produces more vapour; flavours are often perceived more intensely.
• Consumption: Sub-ohm devices use more liquid and more battery power.
• Inhale style: A direct lung inhale feels different from smoking a cigarette. That is why many switchers start with a mouth-to-lung device.
• Operation: Power, coil and liquid must match. This requires a little more familiarisation.

If you are just switching, a simple pod system is often the easier way to start. Read more in the guide What is a pod system?.

Which questions do we hear most often in the shop?

Is sub-ohm vaping more dangerous?

There are no clear study results on this that we can responsibly cite. The BfR generally points out that e-cigarette vapour can contain harmful substances and that more pollutants can be produced when the coil overheats. So stick to the power range specified by the manufacturer.

Can I vape sub-ohm on any box mod?

Only if the box mod and battery cells support the low resistance and the required power. You can find the permitted resistance range in the user manual.

How often do I need to change a sub-ohm coil?

There is no fixed interval. At the latest when the flavour fades or tastes burnt, a new coil is due. More on this in the guide What is a coil in the atomizer?.

Is a sub-ohm tank allowed to hold more than 2 ml in Germany?

The legal requirements for tanks and refill containers are set out in § 14 TabakerzG and § 14 TabakerzV (see sources). The tank volume information in our product descriptions comes from the manufacturer.

Note: This guide is intended exclusively for adults. We sell all products only to persons aged 18 and over. Nicotine is a highly addictive substance. This article does not replace medical advice. If you want to quit smoking, you can find free help on the rauchfrei portal of the German Federal Institute for Public Health.

About the authors – Team Dampfstelle Freiburg: We are an owner-managed specialist shop in Freiburg-Zähringen and have been advising customers in our shop every day since August 2022. Our team has been vaping for over 10 years and knows the devices, liquids and typical problems from personal experience.

Last updated: 14.10.2026 · Product examples and data based on the shop range as of 14.10.2026

Which sources is this article based on?

1. German Federal Institute for Risk Assessment (BfR): E-cigarettes: anything but harmless – questions and answers, as of 08.04.2025 (in German). https://www.bfr.bund.de/fragen-und-antworten/thema/e-zigaretten-alles-andere-als-harmlos/
2. German Cancer Research Center (DKFZ): Facts on smoking – health risks of e-cigarettes, 2024 (PDF, in German). https://www.dkfz.de/fileadmin/user_upload/Krebspraevention/Download/pdf/FzR/FzR_2024_E-Zigaretten.pdf
3. German Tobacco Products Act (TabakerzG), § 14 (in German). https://www.gesetze-im-internet.de/tabakerzg/__14.html
4. German Tobacco Products Ordinance (TabakerzV), § 14 (in German). https://www.gesetze-im-internet.de/tabakerzv/__14.html
5. German Federal Institute for Public Health: rauchfrei portal (in German). https://www.rauchfrei-info.de/
6. Product data: manufacturer information in the product descriptions on dampfstelle-shop.de (retrieved 14.10.2026).