What is the reason for the indoor temperature drop in cold weather?

The reason why the indoor temperature drops in cold weather: Because the outdoor temperature becomes lower, the indoor temperature is already high. According to the principle of heat transfer, high-temperature objects automatically transfer heat to low-temperature objects, and gradually the indoor temperature becomes the same as the outdoor weather temperature.

Heat transfer refers to one of the ways to change the state of the system in the thermodynamic process, and the other way is to do work. The phenomenon that energy migrates from a high-temperature object to a low-temperature object or that heat migrates from a high-temperature part to a low-temperature part in an object without doing work is called heat transfer. Heat is used to measure the change of internal energy of an object during heat transfer.

Heat transfer from high temperature to low temperature caused by the thermal motion and interaction of molecules or atoms that make up the system.

Macroscopic phenomena of heat transfer and heat conduction. Heat conduction can occur in three aggregation states of matter-gas, liquid and solid. The macroscopic law of heat conduction is Fourier law.