The first known central heating systems date back to Ancient Rome, where heating in public baths was provided by underfloor heating, water was heated in furnaces and circulated through stone channels, keeping homes warm.
In the US, about 55% of homes use gas for heating, with gas being the most widely used heating source in the country.
In 17th century Europe, rich people hired servants to sleep in the beds before them to keep them warm, due to the lack of efficient heating systems.
According to the World Bank, around 2.7 billion people around the world use unhealthy heating methods, such as open fires or inefficient combustion appliances, leading to serious health and environmental problems.
In Japan, some traditional houses use the "kotatsu" technique, where the room is surrounded by charcoal in a hole in the floor, allowing the heat to spread throughout the room.
In the late 19th century, the invention of radiators changed the way homes were heated. Originally created to heat steam locomotives, these metal devices quickly became popular for home use.
Denmark is home to the "Copenhagen Geothermal Network", which is the largest in the world. It uses geothermal energy to heat nearly 97% of homes and 99% of public buildings in Copenhagen.
Norway is the first country in the world to introduce a ban on the sale of new domestic heating appliances that run on liquid fuel (such as diesel and oil) in order to reduce harmful emissions.
In the winter of 1940, when Denmark was occupied by the Nazis, people used hot water from the local power station to heat their homes as German soldiers controlled gas and coal supplies.
In China, balls of dried yak feces are produced and sold. They are used as an alternative to wood fuel for heating and cooking.
In 1980 in Georgia, USA, the use of charcoal heaters was banned due to the danger of carbon monoxide poisoning.
In Germany, there is a tradition of building "fireplace devils", which are small ceramic figurines representing little devils that are placed in fireplaces to make it look like the devil is releasing fire.
