At the beginning of the last century there were no centralized heating systems and all rooms were heated by stoves, fireplaces. St. Petersburg is too raw a city most of the year. Without them it is not to do. Wealthy citizens could afford to have fireplaces in every room of their mansions. It was the duty of the servants to heat the stoves. This mansion had a long history. It was originally built in 1740 for the court tailor of the Imperial court. Later it was an apartment house. Then the building changed owners several times. Later, in 1904 - 1907 this house was reconstructed, but all the stoves and fireplaces were preserved. Thanks for Your question, @georgeboya . It's always nice to see interest :))