Because Albert Einstein was so well-known and regarded for his theory of relativity, his many other accomplishments are often overlooked. Einstein was interested in everything, and he spent part of his time figuring out how to improve existing gadgets. He held quite a few patents, including one for a refrigerator that would make the appliances much safer.
In the 1920s, nascent refrigerators used highly toxic, corrosive, or flammable compounds like sulfur dioxide or methyl formate as refrigerants. When passed through tubes and chambers while being pressurized and depressurized, these chemicals could efficiently cool a target chamber. However, moving them around required motors, and thus moving parts, which were subject to breaking down or leaking. When Einstein read a news article about an entire family in Berlin who died in their sleep by breathing in leaking refrigerant fumes, he resolved to do something about it.
He and his colleague Leo Szilard thus spent the early 1930s designing a refrigerator that utilized calmer chemicals – butane, ammonia and water – as well as an ingenious electromagnetic pump. The system required no internal moving parts and was completely sealed. All it needed was an external heat source in the form of a contained natural gas flame.
The refrigerator was a great idea, and might have been a success, if freon hadn't eclipsed it before the bugs could be worked out. Eistein also held patents for a hearing aid, a camera, and even a blouse. Read about all those inventions at Real Clear Science.