Eco (Infrared) heater directly heats the walls, floor and ceiling of a building with thermal mass. Once the thermal mass is warm, the building itself retains the heat for a period of time, so the heater only needs to be on to top up. There is the reason we called 360° Degree heater
Most of the other types of heaters are convection heaters which primarily heat volumes of air, which then has to transfer its heat to the building in order to warm the thermal mass. The problem is that hot air rises to the ceiling (where you don’t want it) and easily escapes with draughts and open doors. The direct transfer of heat to the building is why Eco heaters are more efficient and save energy compared to convection heating. It also more comfortable because you don’t have cold floors and stuffy air.