Conduction vs convection — the two heating systems

TL;DR

• Conduction: herb touches the heating surface. Cheap, fast start.
• Convection: hot air flows through the herb. Cleaner, more even.
• Hybrid systems combine both (Mighty+, Volcano Hybrid).
• Convection = gold standard for flavor and efficiency.

Which system, when?

Conduction fits micro-dosing and entry-level devices (PAX 3, DaVinci IQ2). Downside: uneven extraction, top layer chars faster.

Convection delivers the purest aroma and best extraction (Volcano Hybrid, Mighty+, Arizer XQ2). Price: CHF 200–700, longer heat-up (30 s–2 min).

Heat transfer: contact versus airflow

With conduction, the material lies directly against the heated chamber wall. Due to the design, this is simple, inexpensive, and heats up quickly, but it leads to a temperature gradient: hot on the outside, cool on the inside. Without stirring, the material is depleted unevenly, and during longer sessions, the outer zone roasts. Conduction devices also react sluggishly to temperature adjustments because the chamber mass retains heat.

Convection passes heated air through the material, which ideally does not touch the walls. The extraction is more even, the flavour cleaner, and the temperature control more precise, as there is barely any residual heat between draws. The trade-offs are higher device costs, greater power consumption, and a draw technique that requires a steady, slow pull. Hybrid devices combine both and currently dominate the mid-price segment.

• Conduction: quickly ready to use, cheaper, stir material in between
• Convection: more even and aromatic, more expensive and slower
• Hybrid: practical compromise for most applications
• Adjust grind size to the design — convection requires a loose pack

What this means for choosing a device

For occasional use with short sessions, a conduction device is usually sufficient and significantly cheaper. Those who vape regularly, pay attention to terpene profiles, or use expensive material will get more out of convection and hybrid devices — not only in terms of flavour, but also in yield per gram, which offsets the extra cost over time.

In Switzerland, the following applies: cannabis products with less than 1 % total THC (THC + THCA × 0.877) are not narcotics and are freely available. Liquids and vaporizers also fall under the Tobacco Products Act (TabPG) — sales to minors under 18 are prohibited, and advertising is restricted. The analyzed value of the final product is always decisive, not the information on the packaging.

The correct draw technique in direct comparison

The choice between the two heating systems largely determines how users must inhale in everyday use. With conduction devices, handling is very intuitive because the herb chamber is already heated, and short, shallow draws immediately deliver dense vapour. Anyone using a pure convection device, on the other hand, must actively adjust their draw technique. Since the plant material is only heated by the airflow passing through it, long, slow, and steady draws lasting several seconds are absolutely necessary. Drawing too quickly cools down the heating element, resulting in hardly any vapour.

A common practical mistake is packing the herb chamber too tightly in convection vaporizers. While conduction devices benefit from a tight pack to maximize physical heat contact with the chamber walls, packing too tightly in convection blocks the airway. The hot air can no longer flow freely through the plant material, leading to incomplete vaporization. Users should therefore always pack the material loosely into the chamber so that the convection heat can flow evenly around every single particle.

• Conduction allows short, sip-like draws without much effort.
• Convection requires deep, continuous draws for optimal heat transfer.
• Packing too tightly blocks the necessary airflow in convection devices.
• Conduction chambers usually need to be completely filled for efficient heat transfer.

Cleaning effort and longevity of the systems

The structural difference between the two systems has a direct impact on daily maintenance. With conduction vaporizers, plant resins deposit directly onto the hot inner walls of the herb chamber. Due to the constant exposure to heat, these residues literally bake on, leading to stubborn crusts if not regularly cleaned with isopropyl alcohol. These residues not only impair the flavour of subsequent fills, but can also noticeably reduce the heating performance of the device due to the resulting insulating layer.

Convection devices prove to be significantly easier to maintain in this respect, as the herbs have no direct contact with the heating element. Here, contamination is usually limited to the screen and the airway in the mouthpiece, where the vapour condenses. The cleaning effort is therefore lower in daily use, which increases long-term operational readiness. Nevertheless, due to their more complex airflow, convection models require careful handling to permanently prevent the fine air nozzles from becoming clogged by very fine herb particles.

• Conduction chambers tend to develop stubborn encrustations due to direct material contact.
• Convection paths remain cleaner, but require regular cleaning of the screens.
• Neglected maintenance leads to permanent loss of flavour in conduction.
• Fine particles can block the sensitive air nozzles in convection devices.

Road traffic and legal aspects in Switzerland

For consumers in Switzerland, the choice of vaporizer is also relevant in the context of legislation. Regardless of whether active ingredients are vaporised via conduction or convection, a strict zero-tolerance policy applies to Swiss road traffic. The legal limit is 1.5 micrograms of THC per litre of blood. Anyone who consumes cannabis products must be aware that this limit can be exceeded even after vaporising seemingly legal CBD cannabis with a total THC content of less than 1 percent, leading to an inability to drive.

Since August 2022, medical cannabis in Switzerland has been directly prescribable by doctors without an exceptional permit from the Federal Office of Public Health (BAG). For patients, the precise dosing capability of convection devices is often of great advantage, as it enables exact temperature control. This prevents the formation of harmful substances and allows for a controlled absorption of the active ingredients. Nevertheless, even a medical prescription does not automatically protect against the criminal consequences of participating in road traffic under the influence of THC.

• Strict zero tolerance in Swiss road traffic with a limit of 1.5 µg/L of blood.
• Even CBD cannabis with less than 1% total THC can exceed the limit in the blood.
• Medical cannabis has been directly accessible via medical prescription since August 2022.
• Convection offers patients the most precise dosing and minimisation of harmful substances.

Minimising health risks through temperature control

A key advantage of vaporising compared to traditional smoking is the absence of combustion products. Convection vaporisers offer the highest level of safety here, as the temperature of the air flowing through can be precisely regulated. At temperatures below the combustion threshold, only the desired active ingredients and terpenes are targeted and released. With conduction devices, on the other hand, the direct contact with the hot chamber walls poses a higher risk of localised overheating, which can unintentionally release harmful substances if the material is heated for too long.

Precise temperature selection also makes it possible to control the release of specific compounds in a targeted manner. While volatile terpenes vaporise at low temperatures, other active ingredients require higher temperatures. Convection systems distribute the heat so evenly that the entire plant material is extracted homogeneously. This is gentler on the respiratory tract and minimises the risk of harmful by-products being generated by local hot spots in the chamber, as can occur with poorly designed conduction devices during continuous operation.

• Convection prevents local hot spots and combustion through an even airflow.
• Precise temperature control enables the targeted release of specific active ingredients.
• Conduction devices carry a higher risk of partial smouldering at maximum heat settings.
• Minimising harmful substances is most reliably achieved at temperatures well below the combustion threshold.

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