Session vs On Demand Vaporizers

Once you’ve made the decision to start vaping, there are a lot of different choices you have to make. Do I want a stay at home dry herb vaporizer or a portable one? Do I want a high-tech, smartphone enabled vaporizer or a more basic, simple vape? Dual use or single use? Once you have sorted through the choices and made your decision, you’re confronted with one more, session or on demand?

This may seem like a fairly easy decision since there are only a few on-demand vaporizers available, but they offer a lot of features that session vaporizers don’t. So what is an on demand vaporizer? And is it any better than a session vaporizer? Everything will get a lot clearer once you finish this article.

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Session Vaporizers

Session vaporizers

These are the most common vaporizers, and therefore the most widely available. They are called session vaporizers because once you turn them on, they heat your herb continuously for a “session”. A Typical session is 5-10 minutes, and some vaporizers will allow you to customize the length. But no matter how long the session lasts, once you start vaping, you have to use all the herb that’s in the chamber.

There is no stopping and starting here. The oven of these vaporizers will continue to heat the herb whether you’re inhaling or not, so if you stop inhaling, you will just end up squandering the herb as it wastes away under the hot air.

“Session” vaporizers have no learning curve and are simple and easy to use. We recommend these to all new vapers. A Session vaporizer with a small “solo-size” oven, will be just as efficient with your herbs as an on-demand vaporizer. A couple of good examples are the Arizer Solo 2 and the Atmos Astra 2.

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On-Demand Vaporizers

On-demand vaporizers

On-demand vaporizers only heat up when you inhale from them and cool down as soon as you stop. So instead of having to vape all of your herb during a single session, you can take a hit whenever you want. These types of vapes are sometimes called one-hitters, though the truth is that you can take as many hits as you like, whenever you like, until your herb is cashed. On-Demand vapes tend to have smaller bowls with a lower herb capacity, than session vaporizers.

On-demand vapes typically use convection heating system. This means that the heat is generated away from the oven (and herb), and then pulled into the oven with each inhale. No Air = No Heat. To put that in contrast- “Session” vaporizers typically use conduction heating system- meaning that the heat is generated in the oven.

On-demand vaporizers are relatively rare and they are usually more expensive than session vaporizers. Most also have a learning cureve– such as the Firefly’s inhaling techniche or the Ghost MV1’s loading/ cleaning procedure.

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Session VS Demand, Which One Is Better?

The better type of vaporizer really comes down to personal preference since they both have their ups and downs.

Session Vaporizers:


  • Common and widely available at a variety of different price points
  • They are generally very easy to use
  • They usually provide a consistent vaping experience for the length of the session
  • Most have large bowls that can hold a lot of herb
  • Some of them allow you to set your session length


  • You need to vape all the herb in one session or some of it goes to waste
  • You don’t have a choice in how much—or how little—you want to vape
  • The constant heating means that some session vapes can run hot
  • The constant heating is also a drain on the battery

On Demand Vaporizers:


  • They allow you to use the amount of herb that you want
  • You can vape whenever you want
  • Near instantaneous heat up times
  • Since the heating isn’t constant, battery life is much longer
  • These vaporizers tend to stay cool to the touch


  • They are typically more complex to use than session vaporizers so are not recommended for beginning vapers
  • They are usually more expensive than session vaporizers
  • Since heating is intermittent, vapor quality is not always consistent
  • Small bowls may rankle some users

Oron has been vaping for over ten years, and been 100% combustion free since early 2016. He has tried and tested hundreds of vaporizers with every functionality imaginable. Some of Oron's favorite vapes are the Mighty, Solo 2, and Juul. After switching to vaping, Oron experienced first hand the benefits of being smoke-free and decided to help as many people as possible to make the switch. When Oron is not vaping, he is passionate about photography, technology, gadgets, health & nutrition, physical activities.

  1. An excellent write-up.
    Very much useful information for both the beginner and aficionado.

    S&B would argue their Crafty is a hybrid, (60/40) Convection/Conduction but this is subject to interpretation.
    For my purposes I consider it a Convection Vape, one of the few that you mention in a small band of Convection Vapes that aren’t on-demand.

    However, every unit you highlighted are the trailblazers in their respective categories.
    The info from the write-up is exactly what helps educate the new vape users on choice.
    Great job.

  2. Beginner –

    Is on demand and convection the same thing or different (this is starting to confuse me)? Is the arizer solo 2 on demand/convection. Being new to vaping herb for medical purposes; is there a lost of on demand / convection units (all in composing) I’ve spent hours searching but can’t find such a list.

    I would like the ability to come and go from the vap without having to consume all the product at once.

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