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 you exhaled, you got a thin stream of vapour from the three piece cigalike.
That was back in 2008.
Fast forward nine 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.
Sub Ohm Vaping
- 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
- Practical Guide
- Inhaling Differences
- Resistance: How log can you go?
- Nicotine Levels
- Priming Coils
- Sub Ohm Hardware
- Temperature Control
- E-Liquid Choice
- Considerate Sub Ohm Vaping
When you push electricity through a conductor (such as a coil) it meets resistance.
This resistance is measured in Ohms (Ω).
And 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 couple of years ago, safe & sub ohm capable batteries like the Innokin TC100 were not readily available. The only way to experience sub ohm was by building coils and using them with a mechanical mod.
But sub ohm vaping has matured…
Mechanical mods are still popular, 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 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 way motorway than you are along a country road. Replace the cars with electrons and the road with coils and you should be there 🙂
For more detailed information on how sub-ohm vaping works, including ohms law, see our post The Vaper’s Guide to Voltage, Watts and Ohms.
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 air flow = Better for mouth to lung, more flavour, stronger throat hit and warmer vapour.
- More air flow = Better for direct to 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 which 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 deck, and again once the wick has been installed.
However, if you’re using-pre made coils from a manufacturer like Aspire or Kanger, 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 in our store 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 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 on the wattage/temperature range that can be used with different coils.
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 Furytank coil runs best at 30watts, but a 0.4 triton coil can handle 50w.
(This could be for a number of reasons – amount of wraps on the coil, spacing between wraps and quality of material 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 beautifully 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. That’s controversial – and many 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
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 a minimum of fuss, things are a lot safer as long as you buy quality equipment from reputable brands.
The Very Basics
Screw in a low resistance coil to an appropriate tank. 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 from an e-cigarette.
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 to 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.
You can go very, very low (Aspire Cleito 120 coils, for example, go to 0.16ohms) 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 even 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 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.
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 five minutes, preferably longer.
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.
Enter temperature control (TC) vaping.
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.
Batteries and Box Mods
A great entry level mod for people who want to dip their toes in the sub ohm pool is the Coolfire IV 40W. With power up to 40 Watts, the Cool Fire will support coils with a resistance down to 0.3ohms.
For those who want to use temperature control, the Aspire Archon offers easy to use temperature control. Unlike other mods, these devices automatically detect the type of coil being used making them very simple to set up.
Want to start pushing the boundaries? The Coolfire IV TC100 offers plenty of power and can handle more extreme resistances, making it perfect for tanks like the Cleito 120 with a 0.16 ohm resistance atomiser. But to really push the box, try the Wismec Reuleaux RX2 21700, which comes with a massive maximum wattage of 220 watts.
Pen Style Sub Ohm Devices
Pen-style devices have traditionally been used for a restricted, mouth-to-lung vape. However, we’re increasingly seeing brands like Smok starting to bring out devices which combine the traditional pen-style design with the power to produce some serious clouds of vapour.
One example is the Smok Stick V8. Easy to use, this combines a serious battery life (3000mAh) and a voltage range of 3.4V – 4.2V with 0.4 ohm resistance coils, making it suitable for fans of large clouds of vapour. The new Smok Stick V9 takes this even further with a mesh coil and improved airflow.
Sub Ohm Tanks
When looking for a sub ohm capable e-cig tanks, 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 ecig, 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 written, heat resistance have 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.
If you switch from a higher resistance coil to a sub ohm coil you might find that your regular strength of e-liquid will be too strong, as your device will produce more vapour.
PG:VG ratio can also make a difference in sub ohm devices. An e-liquid with a PG:VG ratio of 50:50 should be fine, but some will find PG heavy liquids (above a 50:50 ratio) too harsh.
Along with the PG:VG ratio, nicotine strength plays a big part in delivering throat hit and satisfaction. Sub ohm devices produce a lot more vapour, and it you may need to reduce nicotine strength so you don’t get too much.
For example, if you move from a 1.8ohm coil with 1.8mg strength e-liquid in a beginner tank like the CE5 to a sub ohm tank like the Falcon II, you might find that 0.6mg or even 0.3mg are strong enough for you.
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!
Steam Engine – For ohms law calculations, coil wrapping and battery drain calculators.