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Aug 30 2019 2 Comments

Ohm’s Law and Sub Ohm Vaping vs Regular Vaping


Sub-ohm vaping is one of the most popular choices amongst vape users but why is it better than regular vaping and is it safe? Today we explore these questions to help you decide if sub ohming is the right choice for you. So let's get started.


Ohm's Law

ohms law

The last time you heard anything about Ohm's law may have been a high school science class but it’s time to bone up on the concepts before you go on your next vaping adventure.


Understanding Ohm's law is an integral part of mastering sub-ohm vaping and in turn, learning to produce the very best build possible.

Put simply, Ohm's law is used to determine current, voltage and resistance in any circuit.

Your personal vaporizer is, indeed, a circuit unto itself and your device probably has variable settings that will allow you to adjust each of these aspects individually.

By extension, once you learn Ohm's law, you can also learn about power and wattage, which is the much more common way of measuring how well a vaporizer will perform.

The Basics

sub ohm for vaping

Ohm’s law itself simply says that I = V/R.


I is the current in your device, measured in amperes. Current is basically the amount of electricity flowing through your device.

V is the voltage.

Voltage is actually a measurement of the potential difference in energy between two points in your circuit.

Some of today’s devices have a variable voltage setting, so it is important to understand how changing the voltage will change your overall performance in this equation.

R is resistance, measured in ohms.

Many vape users are familiar with the term “sub-ohm vaping,” meaning vaping with a total resistance of less than one ohm.

The amount of resistance in your circuit obviously has an impact on the amount of power you are getting out of your device.

The Ohm's law equation can be rewritten and rearranged following the standard rules of math to create the following two equations as well:

· V = I/R

· R = V/I

Using this method you can input any two variables to determine the third, or work in reverse.

Finding Power

The equation for finding power is actually just an extension of the Ohm's law equation that looks like this: P = VI.

P is power, measured in watts.

All manufacturers advertise the wattage of their devices, indicating the amount of power that you will get out of them.

In general, the more power, the bigger the clouds and the stronger the vape.


Okay, we’ve explained Ohms law in general terms but we have yet to explain Ohm's law for vaping and why it’s important.


Ohm's Law for Vaping

1. Battery safety

Vape battery safety is one of the most important aspects of sub-ohm vaping. Batteries are rated at a specific resistance level, and some early sub-ohm vapers encountered battery explosions and overheating because they were not careful to measure the resistance they were working with.

Using the power formula and Ohm's law, you can now do the math yourself to ensure that you are working within the limits of your equipment to prevent dangerous accidents.

In addition,atomizers and cartomizers are sold with pre-set resistance ratings.

If you are curious how these components will impact your vaping, you can plug the numbers into an Ohm's law calculator and see for yourself.

Since Ohm's law is based around a fraction, the impact of changing resistance is not necessarily linear or positively correlated.

This means that less resistance actually creates a higher output instead of the other way around.

That’s why sub-ohm vaping has become so popular.

2. Efficiency

While Ohm's law is certainly about the safety of your build and keeping you away from exploding batteries, it also has implications for the efficiency of your device as well.

Every piece of your circuit has its own impact on the way your device performs, so understanding Ohm's law can change the way you choose your coil wires or the type of battery you use.

If you are trying to get more heat out of a coil with less battery consumption, using a thinner wire will help you out.

This set-up actually preserves some battery but also cools down faster, which may impact the evenness of your vape.

3. Coil type

On the other hand, adding a second coil will heat up slower and take a little more power but will also provide a wider surface area for heating your e-liquid which greatly increases the amount of vapor you produce.

It is also worth noting that resistance is divided between coils, rather than added up, so the more coils you add in the circuit, the lower your resistance goes.

For instance, two 1 ohm coils actually split the resistance in half, so you only have 0.5 ohms to contend with now.

Again, this is in keeping with the fact that lower resistance and more coils create more vapor.

In the beginning Ohm's law can be a bit difficult to understand in terms of how your vaporizer works.

However, there are tons of online resources by experienced builders who can show you exactly what you should be looking for in a balanced build.

There are also charts and calculators designed to help you measure the safety of your device.

When it comes time to buy your new vape tanks or vape mods you can now consider exactly how the whole set-up will perform before you test it out.

4 Key Differences Between Sub-ohm Tanks and Regular Tanks

sub ohm vape tank


Viewing them for the first time, it might appear that there is precious little difference between sub-ohm tanks and regular tanks On further inspection though, there are some major differences that impact the sub-ohm vaping experience.

So what are the critical differences between sub-ohm tanks and regular tanks.

1. Coil Resistance

A regular vape tank uses a coil with a resistance greater than 1 ohm whereas a sub-ohm tank employs an atomizer with a resistance below 1 ohm. This lower resistance of the sub ohm coil means a more rapid heat transfer which results in the production of more vapor and intensified flavor.

2. Airflow

nexMESH sub ohm tank blue


Another major difference that separates sub-ohm tanks from regular tanks is the type and customization of airflow.


As a general rule sub ohm tanks have greater airflow intake with most new sub ohm tanks having three slotted airflow holes to give you all the oxygen you need to make those giant vape clouds.


In contrast the standard regular vape tank only features one or two slotted airflow intake holes.

3. E-liquid Usage

While sub ohm tanks produce a thicker, richer, more flavorful vapor they also have some disadvantages. Often cited as the downside to sub-ohm vaping, a sub ohm tank uses much more e-liquid than a regular tank. This is a result of higher wattage vaping using a coil with less resistance.

4. E-Liquid Mixtures

As sub-ohm vaping vaporizes e-liquid at a much faster rate and generates a much larger volume of vapor, e-liquid choice is important for a satisfying user experience.

Firstly, sub-ohm tanks work better with liquids with a higher vegetable glycerin (VG) to propylene glycol (PG) ratio.  

Secondly , due to the high volume of vapor production it is recommended to use an e-liquid with lower concentration of nicotine. As a guide most sub-ohm vapers use e-liquids with less than 6mg of nicotine. Anything higher than this delivers too much nicotine which can result in the user feeling a little nauseous.  

Sub Ohm Vaping vs Regular Vaping


When looking at the differences between sub ohm vaping and regular (above ohm) vaping the main and determining factor is whether or not the atomizer’s resistance is above or below one ohm.

Consequently, in terms of the overall vaping experience, there are three additional critical differences that come from the increased performance of a sub-ohm device.

These differences combined are the major factors in why sub ohm vaping is popular.

Bigger Clouds

vape clouds with sub ohm tank

If more performance has a meaning for vapers, that meaning can be condensed to larger and more vigorous clouds and expansive hits of flavor.

For those who cloud chase or those who just prefer more flavor on each hit, comparing the performance of a sub ohm device to an above ohm device is similar to comparing the performance of an F1 vehicle to an everyday car.

More Flavor

As the equation goes the more vape produced equates to more flavor.

Therefore as sub ohm vaping requires more e-liquid than vaping at a higher resistance, sub ohm vapers are able to optimize the flavor of their favourite juice on each and every pull.

Warmer Vape

Sub ohm vaping requires more performance resulting in a typically warmer vape than an above ohm experience.

Commercial devices and tanks that provide ample airflow, ensure that the vape experience is pleasurable so as not to cause discomfort but instead, enough to ensure that each hit is warm enough and smooth enough.

Three Ways to Sub Ohm Vape

For those who decide to sub-ohm vape, the choice of an atomizer with a resistance of under an ohm will be necessary.

When breaking down how to sub ohm vape, there are three choices available:

Rebuildable Dripping Atomizers (RDAs)

RDA rebuildable drip atomozer

Before 2012, if you wanted to sub ohm vape, a rebuildable dripping atomizer would have been your only option.

These atomizers allow vapers to build their own coil and wrap their own cotton. Instead of a tank, users would simply drip e-liquid onto the wick.

Rebuildable Tank Atomizers (RTAs)

RTA rebuildable vape tank atomizer

RTAs and RDAs both allow individuals to build and customize their own coils but with an RTA the coils are built within a tank so that dripping your e-juice is not required.

Instead, your e-juice is stored in a tank resulting in a far greater time span between juice refills.

Sub Ohm Tanks

sub ohm vape tank

Commercial tanks have revolutionised sub ohm vaping, making it far more appealing to a larger market.

Since commercial coils are "plug and play", sub ohmers no longer need to build them or maintain them leading to their increasing popularity.

Instead of installing a coil and wicking cotton through it, users can simply install a commercial coil into the tank, top up the tank with e-liquid and begin a sub ohm vaping experience immediately.

Which is better for Sub Ohm Vaping an RBA or a Sub Ohm tank

Not so long ago the answer to this question was quite simple, an RBA will out perform a sub ohm tank every time.

However in recent times, the advances in vaping technology and especially the design of sub ohm tank coils has bridged the gap between the performance of rebuild-able tank atomizers (RBA's) and sub ohm tanks.

While vaping purists will argue that you can't beat an RBA the new conical mesh coil technology employed in the Wotofo nexMESH Sub-Ohm Tank delivers a vaping experience that is set to rival the performance of the best RBA's without the inconvenience of difficult coil builds and wicking configurations.

The Takeaway

The goal of this post was to introduce you to the world of sub ohm vaping and give you a basic education around the topic, however there is a lot more to learn to fully understand the sub ohming phenomenon.

If you're looking for more in-depth information about Ohm's law and sub ohming check out our sub ohm vaping center.

Finally, we'd love to know your views on sub ohm vaping and if you're already a sub ohm vape user what's your favorite sub-ohm tank?

Feel free to join the conversation and comment below.

Happy sub-ohming!

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  • uu on

    This is the best vaping product I have purchased in a long time. The quality is a world better than the other RTA’s and RDA’s I have tried. My only complaint is that the instructions should include how to fully take it apart. I initially was turned on to this RTA . Essentially when ever you need to remove a part make sure to use the top and the vent segment as the points of contact to remove the tube. Also, close the vent holes when filling the tank (you will thank me later).

  • ck on

    This is the best vaping product I have purchased in a long time. The quality is a world better than the other RTA’s and RDA’s I have tried. My only complaint is that the instructions should include how to fully take it apart. I initially was turned on to this RTA from Rip Trippers on youtube. He did show how to correctly swap parts. However, in my excitement I did not remember some of it. Consequently I broke the glass tube it shipped with (the good news is they are super cheap to replace). This was while trying to rebuild it with the bigger tube it comes with. Essentially when ever you need to remove a part make sure to use the top and the vent segment as the points of contact to remove the tube. Also, close the vent holes when filling the tank (you will thank me later).

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