What is the Sharia ruling on wearing only underwear while sleeping and sitting alone at home?

There is no harm in remaining in underwear, with the rest of the body uncovered, if one is alone. However, it is better to cover oneself due to the Prophet's (peace and blessings be upon him) saying: "Allah is more deserving that one should feel shy before Him." Some scholars have explicitly stated the permissibility of uncovering the awrah in solitude for the slightest reason, such as cooling off or protecting one's clothes from dirt.