Germany's insurers fear increased house fires in the winter. The reason is the run on replacement heating systems this year, from wood stoves to radiators.

"We see with concern what adventurous means some tenants and homeowners resort to," said Jörg Asmussen, the general manager of the General Association of the German Insurance Industry (GDV) on Sunday. "We strongly advise against dangerous experiments."

The insurance association sees the greatest risk in open fire, whether candlelight or so-called tealight ovens. Gas-powered radiant heaters generally have no place in closed rooms. Aside from the increased risk of fire, Asmussen warned of toxic combustion gases, including deadly carbon monoxide poisoning.

Electric heaters can also be dangerous

But electric heaters connected to the socket can also be dangerous, according to the GDV. If too many of these devices are connected to the network, the contacts could become extremely hot and catch fire. "Before using powerful electric heaters, you should definitely consult a specialist," said Asmussen. Fireplaces or stoves that have not been used for a long time should be properly connected and checked by a chimney sweep before being used again.

Fears of a lack of gas and the rapid rise in energy prices have caused demand for wood-burning stoves, radiators and other alternative heating systems to rise sharply this year.