A rocket mass heater is an exceptionally efficient type of wood-burning stove that uses minimal fuel to produce maximum heat. With the rise of open-source knowledge and the global DIY movement, rocket mass heaters have become something of an internet phenomenon.

This particular installation – composed of two rocket stoves and a mass heater – brings fire back into the public realm. It is the first of its kind to be built in a shared outdoor space, enabling people to spend more time outside during the winter months while staying cosy and warm. Local residents in Witten were invited to learn, experiment and build the heater together in a public setting. A video tutorial – How to Build a Rocket Mass Heater for Public Space – forms an essential part of the project, ensuring the free and open sharing of this innovative knowledge.

At the heart of the project lies a question: What is permitted in public space? And how can we reclaim our right to the city? Activities like sitting on a sofa or cooking are typically associated with the private sphere, the domestic household. By relocating them to public space, the project reimagines the household as a productive, socially engaged unit, one that is open, diffuse, and deeply connected to its urban context. It challenges the modernist notion of the household as a closed, private unit of consumption.

In this sense, HOT STUFF is a shared, critical public infrastructure – disguised as an artwork.