Germany's unique chimney sweeps, clad in black brass-buttoned jackets and sporting top hats, may seem like glimpses of a bygone era, but the head of their association says they are the key to the country's transition to green energy.

The Ukraine crisis has accelerated the change for the country's 21,000 sweeps, said Alexis Gula from the board of the Federal Association of Chimney Sweeps: "It has been clear to us for some time that this is a transformation process for our profession."

More than 10,000 chimney sweeps in Germany are already trained and certified building energy consultants, he said. "The need for advice among the population is insanely high."

Many new buildings do not have a fireplace and chimney because they are heated either with an electric heat pump or by district heating, but in addition to the classic activities of sweeping and carrying out safety checks, Gula is convinced that many chimney sweeps will specialize in energy and ventilation technology in the future.

Chimney sweeps have more than 200,000 customer contacts in Germany every day and are a neutral contact for their customers.

"They enjoy an insane amount of trust," Gula said.

Sweeps are also seen as a symbol of good luck, with many Germans clamoring to shake their hands or touch their clothes as they ply their trade on the nation's streets.

Customer satisfaction is 98%, Gula said: "The energy and heat revolution will not be possible without the chimney sweep trade."

Chimney sweeps could also look after heat pumps because this is also about efficiency and operational safety.