How Do Vapes Work? A Simple Guide to Modern Vaping

How do vapes work? At first glance, today's devices can look completely different from one another. One might be a tiny refillable pod with no buttons at all, while another has a screen, adjustable airflow and enough settings to make it look suspiciously like a piece of camping equipment.

Pre-filled big-puff vapes are different again. They're designed to provide much of the convenience people once associated with disposable vapes, but the battery is rechargeable and the e-liquid supply can be replaced rather than throwing the entire device away.

Underneath all of those differences, though, how vapes work is fundamentally the same.

A battery supplies electricity to a heating element called a coil. E-liquid is held against that coil by an absorbent wick. When you inhale or press the fire button, the coil heats the liquid and turns some of it into an aerosol, which travels through the device and out of the mouthpiece.

No tobacco is burned, and the e-liquid isn't supposed to burn either.

How Do Vapes Work? Step by Step

Regardless of whether you're holding a £12 refillable pod or a much larger vape kit, a puff follows roughly the same sequence.

1. You inhale or press the fire button. An automatic vape detects your puff with an airflow or pressure sensor. A button-operated vape starts when you press the button.
2. The chipset activates the coil. Electricity flows from the battery through the device's electronics to the heating element.
3. The coil heats up. The heating element reaches the temperature needed to vaporise the e-liquid held against it.
4. The wick supplies e-liquid. Cotton or another absorbent material continuously draws more liquid from the pod or tank towards the coil.
5. An aerosol forms. Some of the e-liquid changes into tiny airborne droplets as it is heated.
6. Air moves through the device. Your inhale pulls fresh air through the airflow openings and past the coil.
7. You inhale the aerosol. The air and aerosol travel through the chimney or pod and out through the mouthpiece.

The whole process happens almost instantly. That's why a modern draw-activated pod begins producing vapour almost as soon as you inhale.

Do Vapes Produce Smoke?

No. A correctly functioning vape doesn't burn tobacco or produce smoke.

It heats e-liquid to create an aerosol.

Most people simply call this “vapour,” and that's perfectly understandable in everyday conversation. Technically, however, vape aerosol isn't a gas in the same sense as water vapour. It's a mixture containing tiny droplets and other constituents suspended in air.

That distinction matters because vaping isn't harmless simply because nothing is burning. Current NHS guidance describes vaping as substantially less harmful than smoking for adults who switch completely, but not risk-free. It isn't recommended for children or people who don't smoke.

What Are the Main Parts of a Vape?

Modern devices can contain plenty of extra features, but almost every vape needs the same basic components.

What Does a Vape Coil Actually Do?

The coil is where the main event takes place.

Despite the name, many modern “coils” don't look much like traditional coiled wire. Mesh heating elements are now extremely common in pods and larger vape kits.

The heating element sits in close contact with absorbent wicking material. The wick draws e-liquid from the surrounding reservoir and holds a thin supply of liquid against the metal.

When the device sends electricity through the heating element, its electrical resistance causes it to generate heat. That heat vaporises some of the liquid touching the wick.

As soon as you finish your puff, the heater switches off and the wick begins drawing replacement e-liquid towards the coil ready for next time.

Why Do Modern Vapes Use Mesh Coils?

Mesh allows manufacturers to create a relatively large heating surface without needing a huge coil.

That can help produce:

• Fast heating when you inhale.
• Even vapour production.
• Good flavour from a compact pod.
• Consistent contact between the heating element and wick.

This is one reason small modern pod kits can produce far more flavour and vapour than the tiny cigarette-shaped e-cigarettes people used years ago.

How Does the E-Liquid Reach the Coil?

It doesn't normally need a pump.

The wick absorbs e-liquid naturally and carries it towards the heating element through capillary action.

Look at a refillable pod and you'll usually see small openings around the coil where the wick is exposed to the e-liquid inside the reservoir.

As the coil vaporises liquid, the wick absorbs more to replace it.

This continues automatically as long as:

• There's enough e-liquid in the pod.
• The wick hasn't become clogged or worn out.
• The liquid isn't too thick for the coil.
• You aren't vaping so rapidly that the wick can't resaturate between puffs.

How Does an Auto-Draw Vape Know When You're Inhaling?

Many modern vapes don't need a fire button at all.

Inside the device is a sensitive sensor that detects the change in airflow or pressure created when you inhale through the mouthpiece.

The chipset sees that signal and sends power to the coil.

Stop inhaling and the device stops firing.

Modern auto-draw systems can respond extremely quickly, which is why there may be almost no noticeable delay between beginning your puff and feeling vapour.

Some refillable pod kits include both automatic activation and a fire button, allowing you to use whichever method you prefer.

How Do Refillable Vapes Work?

A refillable vape allows you to add bottled e-liquid yourself.

The most popular modern version is the refillable pod kit. Instead of a traditional glass tank screwed onto a large metal mod, a compact plastic pod clicks or slides into the top of the battery.

The pod may contain:

• A built-in coil that stays in the pod.
• A removable coil that can be replaced separately.

Fixed-coil pods have become particularly popular because they're so simple. You fill the pod through a small port, vape until the coil eventually wears out and then replace the entire pod.

The battery section stays with you and is recharged through USB-C.

What Happens When You Use a Refillable Pod?

A simple draw-activated refillable vape works something like this:

1. You fill the pod with suitable e-liquid.
2. The wick absorbs the liquid around the coil.
3. You put the pod into the device.
4. The device detects the resistance of the pod and may automatically choose an appropriate power level.
5. You inhale through the mouthpiece.
6. The draw sensor activates the coil.
7. The coil vaporises e-liquid from the wick.
8. You stop inhaling and the heating cycle ends.

That's essentially it.

A device might have a display, adjustable airflow or several power modes, but those features are controlling the same basic process.

How Do Pre-Filled Pod Vapes Work?

A pre-filled pod vape removes the filling step.

The reusable part contains the battery and electronics, while the pod arrives already filled with e-liquid and contains the coil and wick.

You attach the pod to the battery and vape. When the liquid is gone or the coil is finished, you remove that pod and attach another one.

From the user's point of view, this is about as simple as vaping gets:

• No e-liquid bottle.
• No filling port.
• No separate coil replacement.
• No wattage setting on most basic models.

The battery is simply recharged and used again.

How Do Big Puff Vapes Work?

Modern disposable vape alternatives — often called big puff vapes — are a development of the same pre-filled idea.

Old disposable vapes contained a battery, coil and e-liquid supply permanently sealed inside a device that was thrown away when the liquid ran out. Those single-use vapes can no longer legally be sold in the UK.

Today's alternatives are designed to be reusable. The battery can be recharged, and the e-liquid-containing components can be removed and replaced.

What makes many big-puff systems unusual is the way they manage their e-liquid supply.

2 ml Pod + Refill Container

A common design combines a small 2 ml pod containing the coil with a larger replaceable refill container.

The refill section doesn't generally dump all of its liquid into the pod at once. Instead, an internal feeding or wicking system gradually supplies the working reservoir as you vape.

So from the outside, the vape can look like one large pre-filled unit, but internally there are separate parts performing different jobs:

• The rechargeable battery supplies power.
• The 2 ml pod contains the coil and active vaping reservoir.
• The refill container holds additional e-liquid.
• An internal liquid path keeps the pod supplied.

When the e-liquid is finally exhausted, you replace the pre-filled pod/refill assembly rather than throwing away the battery.

Are Big Puff Vapes Basically Disposable Vapes?

They can feel very similar to use, but there's an important structural difference.

That's why big-puff systems have largely taken over the convenience-vape category in the UK following the disposable vape ban.

Why Were Disposable Vapes Banned?

Single-use vapes became illegal for UK businesses to sell or supply from 1 June 2025.

For a vape to qualify as reusable under the current rules, it must have a rechargeable battery and a refillable or replaceable e-liquid container. If its coil is a separate component, that also needs to be replaceable.

This is why the modern replacement for a disposable isn't simply a disposable with a USB-C port.

The e-liquid system also has to be designed for reuse.

What Is Inside Vape Juice?

Most e-liquid is built around two main carrier liquids:

• Propylene glycol (PG)
• Vegetable glycerine (VG)

Flavourings are added to those base ingredients, and nicotine may be included if the product is intended to contain it.

Some formulations can contain small amounts of other ingredients, but describing vape juice as mainly water — as older vaping guides sometimes did — isn't accurate.

PG and VG also affect the way a vape behaves.

PG is relatively thin and is commonly used in liquids for small MTL pods. VG is much thicker and produces dense visible vapour, making higher-VG liquids well suited to more powerful RDL and DTL devices.

How Does Nicotine Get from a Vape into Your Body?

If an e-liquid contains nicotine, that nicotine becomes part of the aerosol produced by the device.

When you inhale the aerosol, nicotine is absorbed into the body.

The amount you receive from a puff doesn't depend on the bottle strength alone.

It can also be affected by:

• How much vapour the device produces.
• The power and coil design.
• Your puff length.
• Your airflow setting.
• How frequently you vape.
• The nicotine formulation.

This is why high-strength e-liquid is normally paired with smaller, lower-powered MTL devices, while high-output DTL vapes generally use much lower nicotine strengths.

What Do PG and VG Actually Do?

What Does Coil Resistance Change?

Coils have an electrical resistance measured in ohms (Ω).

Modern pod ranges might offer several versions such as:

• 1.2Ω
• 0.8Ω
• 0.6Ω
• 0.4Ω

In general, higher-resistance pods are commonly designed for lower-powered, cooler MTL vaping. Lower-resistance pods can usually operate at higher power and produce warmer, more abundant vapour.

Don't read too much into the resistance number on its own, though. Coil construction, airflow and recommended wattage matter as well.

A modern 0.8Ω pod can be technically sub-ohm while still behaving like a compact MTL vape.

How Does Adjustable Wattage Work?

Some vapes let you decide how much electrical power goes to the coil.

That setting is measured in watts.

Increasing power within the coil's recommended range can generally make the vapour:

• Warmer.
• Denser.
• More intense.

It also causes the coil to use e-liquid and battery power more quickly.

Many beginner-friendly devices remove this decision entirely. Insert the pod and the chipset detects its resistance, then selects a suitable output automatically.

That's one reason modern pods can have surprisingly sophisticated electronics despite having only one button — or none at all.

How Does Adjustable Airflow Work?

Airflow controls how much air reaches the coil while you inhale.

Close the airflow and the draw becomes tighter. Open it and the inhale becomes looser.

This helps create the three main modern vaping styles:

The basic heating process remains exactly the same in all three cases. You're simply changing the amount of air and vapour moving through the system.

Why Do Some Vapes Crackle and Pop?

A gentle crackling noise is often completely normal.

You're hearing e-liquid rapidly vaporising on the hot surface of the coil.

Large or powerful coils may sound louder than tiny MTL pods because they're vaporising more liquid at once.

A sudden loud spit of hot liquid is different. That can mean excess e-liquid has flooded the coil, allowing liquid droplets to reach the mouthpiece before they've been fully vaporised.

Why Does a Vape Stop Working When the Pod Is Empty?

The device itself may still switch on, but a coil can't work properly without e-liquid.

The wick needs to remain wet so that the heating element vaporises liquid rather than overheating the cotton.

If you continue vaping an empty pod, you'll eventually get a dry hit and can permanently damage the coil.

A transparent pod is useful for exactly this reason: you can see how much liquid remains rather than having to guess.

Why Do Vape Pods Eventually Need Replacing?

A coil doesn't remain clean forever.

Every time e-liquid is heated, some non-volatile material can remain behind on the heating surface and wick. Sweetened liquids can produce particularly noticeable residue.

Eventually, you may notice:

• Weaker flavour.
• Reduced vapour production.
• A darker-looking wick.
• A burnt or stale taste.
• More frequent leaking or gurgling.

With a fixed-coil pod, you replace the pod. With a traditional tank or replaceable-coil pod, you can replace the coil separately.

Why Do Vapes Leak?

The e-liquid reservoir needs air openings so that you can inhale through the device, which means a vape can never simply be a completely sealed bottle.

Leaking can happen if liquid gets into parts of the airflow system where it shouldn't.

Common causes include:

• A worn-out pod or coil.
• Damaged seals.
• Overfilling.
• Using liquid that's too thin for the coil.
• Leaving the vape in extreme heat.
• Flooding the coil by drawing too hard.

Modern pods use increasingly sophisticated internal structures to reduce leaking, but no liquid-filled vaping device is completely immune to it.

Why Does a Vape Need a Battery?

The battery provides the electricity needed to generate heat.

Small modern pod systems usually have an internal rechargeable battery. Larger devices may also use removable rechargeable cells.

The battery powers more than just the coil. Depending on the vape, it may also run:

• The screen.
• LED indicators.
• The puff sensor.
• The control chipset.
• Power regulation.
• Battery and coil protection systems.

This is why even very simple vapes are really small electronic devices rather than passive e-liquid holders.

Why Does My Vape Have a Screen?

A screen isn't necessary for vaping, but it can show useful information such as:

• Battery level.
• Coil resistance.
• Selected wattage.
• Puff count.
• Power mode.
• E-liquid level on some pre-filled systems.

In other words, the screen doesn't fundamentally change how the vape works. It simply gives you more information and, on adjustable devices, more control over what's happening.

Are Modern Vapes More Complicated Than Older E-Cigarettes?

Internally, yes. From the user's point of view, often the opposite.

An old refillable e-cigarette could require separate coils, complicated filling methods and manual power adjustment.

A current refillable pod can automatically:

• Detect which pod you've inserted.
• Select a suitable power level.
• Activate when you inhale.
• Monitor the battery.
• Stop firing when something isn't right.

You may only need to fill it and inhale.

Modern big-puff vapes simplify things even further because the e-liquid is supplied in pre-filled replacement components.

How Are Vapes Different from Cigarettes?

The most fundamental difference is combustion.

A cigarette burns tobacco. Burning produces smoke containing thousands of chemicals, including tar and carbon monoxide.

A vape doesn't contain burning tobacco. It heats an e-liquid to produce an aerosol instead.

That's why NHS guidance says vaping exposes users to fewer toxins and at lower levels than smoking and can be useful for adults switching away from cigarettes.

That doesn't make vaping completely harmless, and vaping isn't recommended for non-smokers or children.

Refillable Vape or Pre-Filled Vape: Which Works Best?

Mechanically, neither is inherently more advanced. Both can use excellent modern coils and electronics.

The real difference is how much involvement you want.

Whichever type you choose, the actual puff is produced in essentially the same way: battery, coil, wick, e-liquid and airflow all working together.

Frequently Asked Questions

The Bottom Line: How Vapes Work

Modern vapes look very different from the cigarette-shaped e-cigarettes that introduced many people to vaping, but the underlying idea is surprisingly straightforward.

A battery powers a coil. A wick keeps that coil supplied with e-liquid. The coil heats the liquid to create an aerosol, and your inhale carries that aerosol through the mouthpiece.

Everything else — mesh coils, adjustable wattage, automatic draw sensors, refillable pods, pre-filled pods and big-puff refill systems — is essentially a different way of making that same process more convenient, efficient or customisable.

So if you've ever looked at a modern vape with a colour display, airflow slider and three different power modes and wondered whether you need an electronics qualification to understand what's going on, you don't.

Underneath it all, the device is still doing the same five things: storing e-liquid, moving it to a coil, heating it, mixing the resulting aerosol with air and giving it somewhere to come out.