A local space heater should come with an energy label indicating its energy efficiency on a scale from A++ (most efficient) to G (least efficient), applicable from 1 January 2018.

The relevant Regulation (EU) 2015/1186 can be found here.

The label provides important information such as the company that made or placed the product on the market, the model, the energy efficient class, the direct and if relevant the indirect rated heat output in kW, etc.