Hydronic Shell Technologies aims to simplify and reduce the cost of retrofitting old buildings for energy efficiency. The startup designs prefab panels with integrated insulation, heating, cooling, and ventilation, attached externally to old apartment buildings. The innovation was inspired by a New York City law requiring large buildings to cut energy use.

Founder David Goldstein's design uses heated water pipes in the facade for warmth, cutting energy use by over 90%. The company plans a pilot project in Syracuse, New York, with the goal of making the retrofitting process more economical and feasible for the widespread transformation of existing buildings.