Technicall....That's just called either convection, conduction, or radiation for transferring the heat from a heater (where heat is generated by electrical resistance), with a different term depending on the method of heat transfer (likely convection+conduction). Combustion requires a chemical change, of which there is none in the process of making vapor, and therefore there is no reaction (in a chemical sense)
Combustion is the act or process of burning. It is a chemical combination attended by production of heat and light. A battery is a device that stores electrical energy in the form of chemical energy, and convert that energy into electricity. The chemical process that allows the release of that energy is called oxidation reduction (or Redox). Combustion is a type of oxidation reduction, but so is rusting.
I'm seriously thinking about relocating to a state where it's legal, but I'm waiting to see if Trump is gonna get mixed up in that business first...I know he is all about businesses that flourishes but I'm not sure where he stands on legalizing marijuana...