Device for heating room air and a liquid

A device for heating room air and a liquid, comprising:

• an air inlet, an air outlet, a liquid inlet, a liquid outlet, an energy unit, a heat transfer device, a medium container, a medium line, a conveying device and a control unit,
• wherein room air to be heated enters the device via the air inlet,
• wherein heated room air exits the device via the air outlet,
• wherein liquid to be heated enters the device via the liquid inlet,
• wherein heated liquid exits the device via the liquid outlet,
• wherein the energy unit produces thermal energy,
• wherein the heat transfer device transfers the thermal energy produced by the energy unit to the room air and/or the liquid,
• wherein the medium container serves to receive the liquid,
• wherein the medium line serves to conduct the liquid,
• wherein the heat transfer device and the medium line are configured and arranged relative to each other such that the heat transfer device transfers thermal energy to liquid present in the medium line,
• wherein the conveying device serves to move liquid from the medium container to the medium line, and from the medium line to the medium container,
• wherein the control unit controls the conveying device and/or the energy unit, and
• wherein in case the device is intended to heat only room air in an air mode, the control unit, in a preparation step, controls the conveying device and/or the energy unit such that liquid runs out of the medium line due to the gravitational force and/or liquid in the medium line is heated up to an evaporation temperature of the liquid.