Technological advances during industrialisation brought major changes to the kitchen. Iron stoves, which enclosed the fire completely and were more efficient, appeared. Early models included the Franklin stove around 1740, which was a furnace stove intended for heating, not for cooking. Benjamin Thompson in England designed his "Rumford stove" around 1800. This stove was much more energy efficient than earlier stoves; it used one fire to heat several pots, which were hung into holes on top of the stove and were thus heated from all sides instead of just from the bottom. However, his stove was designed for large kitchens; it was too big for domestic use. The "Oberlin stove" was a refinement of the technique that resulted in a size reduction; it was patented in the U.S. in 1834 and became a commercial success with some 90,000 units sold over the next 30 years. These stoves were still fired with wood or coal. Although the first gas street lamps were installed in Paris, London, and Berlin at the beginning of the 1820s and the first U.S. patent on a gas stove was granted in 1825, it was not until the late 19th century that using gas for lighting and cooking became commonplace in urban areas.