Indoor heating refers to the methods used to maintain a comfortable temperature inside buildings during cold weather. Common systems include furnaces, boilers, and heat pumps, which generate warmth through various means, such as burning fuel or using electricity. These heating systems distribute warm air or water throughout the space, ensuring even heating. Proper insulation and sealing of windows and doors are also important to enhance efficiency and reduce energy costs. Regular maintenance of heating systems helps ensure safety and optimal performance during the winter months.