Updated: August 2023
I held on to the thin white tube, put it to my mouth and inhaled for the first time on an e-cigarette.
It wasn’t quite smoking, but it was certainly a good replication.
And when I exhaled, I got a thin stream of vapour from the three-piece cigalike.
That was back in 2008.
Fast forward 15 years and things are very different.
Sometimes I can’t even see the computer screen I am typing on now.
And one of our staff even managed to block the moon during an eclipse.
The production of these truly massive clouds of vapour is down to one thing.
- What is sub-ohm vaping?
- How does sub-ohm vaping work?
- Confused about resistance?
- Ohms Law
- Sub-ohm vaping power settings
- Why do vapers sub-ohm?
- Is sub-ohming safe?
- Practical guide
- Sub-ohm hardware
- Sub-ohm e-liquid
- Wrapping up
When you push electricity through a conductor (such as a coil) it meets resistance.
This resistance is measured in Ohms (Ω).
When you use coils with a resistance of less than 1 ohm, you are sub-ohm vaping.
Today, sub-ohm resistances are common in off-the-shelf tanks and pre-built coils, but it hasn’t always been this way.
Only a few years ago, safe & sub ohm capable batteries like the Smok Morph 3 were not readily available. The only way to experience sub-ohm vaping was by building coils and using them with a mechanical mod.
But sub-ohm vaping has matured…
Mechanical mods are still available, but battery and chip technology has moved on a great deal. The evolution of hardware has brought safe sub-ohm vaping to the masses.
There are two ways to increase the amount of vapour you get from your coil. One is to increase the power of your battery. The more power you provide to your coil, the hotter it gets and the more vapour you can produce.
But there are limits to the amount of power you can put through a coil before it stops producing more vapour and starts producing excessive heat.
Excessive heat can cause the vapour to get uncomfortably hot or even burn your wick. Burnt cotton doesn’t taste too good!
By combining a lower resistance coil with more airflow you can use more power before you start creating excessive heat.
To lower the resistance of your coil, you can use a thicker wire. If you apply the same power to two wires of the same length but different thickness, the thicker wire will heat up more slowly.
To reach a similar temperature in the same time with a lower resistance coil (thicker wire), you need to provide more power.
By increasing the thickness of the wire, you also increase the surface area of the coil contacting the wick. This allows it to vapourise more e-liquid and therefore produce more vapour – leading to those clouds sub ohmers love!
Think of a country road (high resistance) versus a three lane motorway (low resistance). You’re going to get a lot more cars along a three lane motorway than you are along a country road. Replace the cars with electrons and the road with coils and you should be there
But there is more to it than just resistance...
Larger air holes are also essential to allow enough airflow to cool the coil and the vapour.
When the vapour gets too hot it can be unpleasant, and the heat can be transferred to your drip tip if it’s metal.
Adjustable airflow on tanks allows you to adjust the airflow until it’s right for you. As a general guide:
- Less airflow = Better for Mouth-to-Lung, more flavour, stronger throat hit and warmer vapour.
- More airflow = Better for Direct-Lung, more vapour, less intense flavour, slightly cooler vapour
You’ll see a lot of talk about ohms law.
But there are plenty of sub ohmers who don’t understand ohms law.
If you’re into rebuildables or mechanical mods, a knowledge of ohms law is important for your safety.
Today, most regulated box mods come with in-built safety systems to stop you from using a coil with a resistance too low for the battery, or even worse, a coil that creates an electrical short.
A mechanical mod has no safety systems. If you attach a coil that is shorting, there is nothing to stop you from completing the circuit when you press the power button.
In my experience, shorts are quite rare when building coils but missing the target resistance is much more common. If you’re into building coils, you should be aware of the risk of shorts, and be on the lookout for any contact between the coil and base.
For this reason it’s important to check the resistance of handmade coils using an ohm meter before attempting to use them. I’ve always measured twice; once when the coils is fixed to the deck, and again once the wick has been installed.
However, if you’re using pre-made coils from a manufacturer like Aspire, Geekvape or Smok, there’s no need to measure the resistance before use, and the chances of a short are slim to none.
A short is bad because essentially you are making a direct connection between the positive and negative terminals of your battery.
All box mods available on E-Cigarette Direct are regulated with in-built safety, and will not work if the resistance of the coil is too low or there is a short.
Many vapers simply start at a relatively low wattage or temperature and with a low resistance coil, and slowly increase the wattage/temperature until they get satisfactory clouds. However, if you are inexperienced and go too high, you may burn out your coil.
A good starting point is the manufacturer’s instructions that come with sub-ohm tanks. Many of these advise the wattage/temperature range that can be used with different coils. You’ll also find these on the individual product pages on E-Cigarette Direct.
That may well beat using charts. That’s because coils from different manufacturers, but with the same resistance, often have slightly different ideal wattage/temperature ranges.
For instance, a 0.3 Ω Furytank coil runs best at 30 watts, but a 0.4 Ω triton coil can handle 50w.
(This could be for a number of reasons – the amount of wraps on the coil, spacing between wraps and the specific alloy used e.t.c.)
Most people sub ohm because they want more vapour. It can be very satisfying to see large plumes of vapour filling a room and dancing before your eyes.
It can also increase throat hit, although typically sub-ohm vapers use high VG e-liquid to offset the increased throat hit as a high PG e-liquid could be too harsh. The larger juice holes are also necessary to cope with VG e-liquids, which are much thicker than high PG e-liquids.
Some people also think that sub-ohm vaping leads to better flavour.
High PG e-liquids carry more flavour than the high VG e-liquids used for cloud vaping. However, when you sub-ohm, you get a lot more vapour, which can counterbalance any loss of taste.
Still, some of the recommendations in our guide to flavour chasing are completely opposite to what you need to do for sub-ohm vaping.
Sub-Ohm Vaping Pros
- Tonnes of vapour
- May produce more flavour
- Warmer vapour
Sub-Ohm Vaping cons
- Uses more e-liquid
- May require a change in inhale technique
- Battery will be drained much faster
- Coils don’t last as long
Sub ohming has a bad reputation when it comes to safety.
But much of the danger occurs when people build their own coils and mods or use mechanical mods. If you want to go down this route, ensure you are fully clued up first.
If you just want to achieve large clouds with minimum fuss, things are a lot safer as long as you buy quality equipment from reputable brands.
Screw in a low resistance coil to an appropriate tank. Ideally, you’ll use a mesh coil, as this has a larger surface area than standard coils. You want to use a coil much lower than one ohm.
You’ll also need a vape battery that can handle higher power.
Starting at a low power setting, slowly crank the wattage/temperature up in small increments until you are getting satisfactory vapour. Refer to the manufacturer’s recommendation if available, but remember that the setting provided might not be the right settings for your personal taste.
There’s essentially two ways to inhale when you vape.
The first is Mouth-to-Lung, where you take the vapour into your mouth and hold it there briefly before inhaling.
The second is Direct-Lung, where you inhale the vapour directly into your lungs.
Most sub ohmers inhale the vapour directly into their lungs. That’s because:
- You can take in more vapour; the volume of your lungs is much greater than the volume of your mouth.
- Direct to lung reduces the throat hit as you have a constant flow of air cooling down the vapour.
For more information see our complete guide to vaping inhale techniques.
Coils have evolved since we first wrote this post.
There was a time when anything below one ohm was considered low resistance. Nowadays, many MTL coils use a resistance of below one ohm, and true cloud chasing coils are much lower.
You can go very, very low (Smok RPM 2 coils, for example, go to 0.16 Ω) but you need to ensure that you have the power to be able to make use of them.
A 0.16 ohm coil, for example, is probably not going to fire on less than 50 watts, and to get a decent use out of it you are probably going to need to go to 70 watts and above.
If you’re just starting, you’re probably better off using a less extreme coil and lower wattages, as you’re less likely to burn the coil out at the outset.
Because you take in a lot more vapour when you sub ohm, your body absorbs a lot more nicotine than it does with regular vaping. As a result, you’ll find most sub ohmers use very low levels of nicotine – 0.3% is quite common.
Be careful before using your regular level of nicotine for sub ohming – you could find yourself experiencing an unpleasant nicotine rush.
Whether you are sub-ohm vaping or not, dry hits are unpleasant.
When changing your coil, always make sure you leave a few minutes between filling your tank and vaping. You can speed this up slightly by priming the coil before filling your tank. (You should prime all coils, but it’s particularly important with sub ohm coils.)
Priming is simple. Drop some e-liquid into any juice holes on your coils and onto the mesh in your coil. Attach your coil, add e-juice and allow to soak for at least ten minutes.
Learn more: How to prime vape coils
After playing around with your device in wattage/voltage mode, you may think you have found the perfect resistance/wattage combination.
But there’s one problem…
When your press your fire button, a constant current flows through your coil.
If you've set your battery to 70 Watts, your battery will send a constant current to the coil while you hold the button down.
This can become a problem if you take very long draws from your device; your coil will continue to heat up while you hold down the button. Once the temperature gets too high, you can lose flavour or even burn the wick in your tank.
TC devices constantly measure the resistance of your coil, and from that can work out the temperature of your coil.
The device will then reduce the power going through the coil in order to maintain a constant temperature, massively reducing the risk of burnt out coils.
TC devices were originally tricky to use, but new devices are getting progressively easier to use and better at applying temperature control.
One good option if you are starting out is the Eleaf iStick Power. This works with almost any type of temperature control coil. We also like the fact that, if you’re overdoing things with temperature, you get a message saying “You’re too hot, slow down”.
Eleaf iStick Power
- Compatible with almost any Temperature Control coil type
- Easy-to-use menu
- Remembers power settings for up to 10 different coils
- Massive 5000mAh battery
Sub-ohm pod mods
Since we first wrote this guide, pod mods came on to the scene. A cross between a pod and a mod device, these combine some of the simplicity of a pod system with some of the power of a mod system. That makes them a great choice for people starting out with sub-ohm vaping.
Our current favourite for sub-ohm vaping is the Voopoo Drag E60. The device provides simply superb flavour, can deliver up to 60W and has a beginner-friendly Smart Mode option.
For more options see our Best Pod Mods roundup.
Sub-ohm vape kits
A great entry level mod kit for people who want to dip their toes in the sub ohm pool is the Innokin Adept Zlide, which is easy to use and works with coils as low as 0.3Ω.Want to start pushing the boundaries? Try the Smok Morph 3, which comes with a massive maximum wattage of 230 watts.
Smok Morph 3 Mod
- Up to 230W of adjustable power
- Powered by dual 18650 batteries (not included)
- Stylish metal & leather design
- Includes both Power & Temperature Control modes
- TFT screen displays all vaping data
Sub-ohm vape pens
You’d usually use a vape for a restricted, Mouth-to-Lung vape. However, there are options that combine the traditional vape pen design with more power and low resistance coils.
The Geekvape Mero Aio combines ease of use (it has just three power settings) with a 0.4Ω coil. It’s not going to block the sun out, but it will make a great introduction to sub-ohm vaping.
The Voopoo Doric 60 is still easy to use, but takes things a bit further. It has a single 60 watt output setting and works with 0.2Ω coil to produce some serious clouds of vapour.
Sub ohm tanks
What is a sub-ohm tank?
Strictly speaking, a sub-ohm tank is any tank which works with coils with a resistance of lower than 1 ohm. In reality, though, there’s a lot more to it than that.
So when looking for a sub ohm capable vape tank, think about the following factors:
Due to the increased heat generated by sub-ohm vaping, most sub-ohm tanks offer greater airflow. You’ll usually find larger air-holes (often adjustable) and some tanks feature both top and bottom airflow controls.
When you use your vape, the metal around the tank will heat up. If you use your device enough, this can become a problem if you have a metal drip tip, but not with derilyn or acrylic.Update: Since this post was first written, heat resistance has improved with innovative Mesh and Plexus coils. The increased surface area of these coils mean there is a larger and more even interface between the coil and the e-liquid. They also come with a host of other benefits. See our Mesh and Plexus coil guides for more information.
Drip tips for tanks are often much wider than regular drip tips in order to allow more vapour to flow through.
You’ll also find larger holes in the coil. These ensure enough e-liquid flows through to the coil even when it is working at high temperatures, and help avoid coil burn out. They are also able to handle thicker high VG e-liquids.
Top tanks for sub-ohm vaping
Since we last update this, the Vaporesso iTank II has replaced the Horizon Falcon as our favourite tank for cloud vaping. In fact, it's the best sub-ohm tank we've even seen.
Unlike most other cloud-vaping tanks, it doesn't experience problems with leaking, and the coils can last up to 7 days. It produces great flavour, has superb build quality and the quick release button makes it easy to use.
A great runner up is the Geekvape Zeus Tank, which comes with large wicking holes to absorb high VG e-liquids and excellent airflow controls.
When you sub ohm, you need to think about the VG:PG ratio of your e-liquid. In a nutshell, the higher the VG, the more clouds you will get. On the other hand, higher VG juices are harder on coils, so you do have to balance your desire for clouds against shorter coil life.
Can you use e-liquids with a VG:PG ratio of 50:50 in a sub-ohm tank?
I’ve often been asked if you can use 50:50 e-liquids in a sub-ohm vape tank. If you are using a tank designed for clouds, with low resistance coils and high power levels, you will probably find that the throat hit is too harsh.However, you can use 50:50 e-liquids in a sub-ohm tank if you really lower the wattage. In general, though, you are best off using 50:50 e-liquids in a Mouth-to-Lung tank such as the Innokin Coolfire Z60.
Some vapers are completely opposed to sub-ohm vaping.
The massive clouds that are produced can upset non-vapers and worry people who think that vaping is unhealthy. (A proportion, according to data from Action on Smoking and Health, that is growing).
It’s also more likely to lead to bans in pubs and companies, and could lead to difficulties for people who just want a quiet vape using a regular device.
And when we surveyed vapers on vaping etiquette, only 3% thought it was acceptable to blow large of clouds of vapour anywhere.
Obviously it’s fine to sub-ohm at a vaping convention, and not in a school playground, but there’s a whole range of places where you will need to use your best judgement!
Sub-ohm vaping used to be the preserve of the vape nerd, but advances in technology have made clouds available to more people.If you are just starting out, it’s well worth starting with a mid-range device, so you can get used to working with higher power levels and low resistance coils. As you gain in confidence and skill, you can then go for higher power and lower resistance - and really ramp up the clouds.
Steam Engine - For ohms law calculations, coil wrapping and battery drain calculators.