Hot air rises because gases expand as they heat up. When air heats up and expands, its density also decreases. The warmer, less dense air effectively floats on top of the colder, denser air below it. This creates a buoyant force that causes the warmer air to rise.

The cooler air stays more dense, but as the hot air loses temperature it becomes more dense causing it to fall. In terms of how this heats a room, this exchange of gas of different density causes a convection current around the room and as the air passes the radiator that will warm it causing it to rise.

A modern space heater can be very safe to keep on for long unsupervised periods of time, including while sleeping. Be sure your heater is certified by one of the three major testing organizations and has features like automatic shutoff, tip over protection, a shut off timer, and adjustable thermostat.

Convection currents are created when the air above your radiator heats and then cools and is then heated again. This process happens continuously whilst you have your heating on and the current moves the heat around the room making it nice and warm and toasty.

The sun’s radiation strikes the ground, thus warming the rocks. As the rock’s temperature rises due to conduction, heat energy is released into the atmosphere, forming a bubble of air which is warmer than the surrounding air. This bubble of air rises into the atmosphere.

Throughout the universe, it’s natural for energy to flow from one place to another. And unless people interfere, thermal energy — or heat — naturally flows in one direction only: from hot toward cold. Heat moves naturally by any of three means.

Heat flows from hot to cold objects. When a hot and a cold body are in thermal contact, they exchange heat energy until they reach thermal equilibrium, with the hot body cooling down and the cold body warming up. This is a natural phenomenon we experience all the time.

Cold air flows downward according to hot air because it is more dense and sinks while hot air rises. In hot room the air will be much thinner thus reducing the pressure so the air flows from cold room to hot rooms.

The atoms of hot body have higher Kinetic Energy than that of cold body. So the atoms of hot body move and collide with the atoms of cold body and transfer heat. So the atoms of hot body move and collide with the atoms of cold body and transfer heat.

In physics, the second law of thermodynamics says that heat flows naturally from an object at a higher temperature to an object at a lower temperature, and heat doesn’t flow in the opposite direction of its own accord.

The atoms of the system with higher temperature will gain the heat energy and the vibration of these atoms will increase. The atoms or molecules on the system with lower temperature have lower temperature and are not vibrating. So, we can say that heat always flows from higher temperature to a lower temperature.

Heat is always transferred from the object at the higher temperature to the object with the lower temperature. For a gas, the heat transfer is related to a change in temperature. The temperature, pressure, and volume of the gas determine the state of the gas.

Complete answer: Thus, heat energy always flows from a body at higher temperature to a body at lower temperature.