In fact, the percentage of foreigners renting courtyards is about 10 to 20 percent, according to Joanna Real Estate's business data.

"A key factor living in a siheyuan was the temperature of the house," Marc said. "I never had to use the air-conditioning in the summer because the temperature was kept low in the courtyard. And it was not very cold in the winter because the walls are quite thick."

Wealthy foreign expats can also renovate siheyuan according to their tastes and needs as long as they respect the structure of the building.

Naturally, there are drawbacks to living in a courtyard house. Parking space can be scarce and Western amenities sometimes out of reach.

"It was difficult to find a parking space close to my courtyard," said Marc. "But in the end I managed to find a car park that belonged to another residential building close by."

Still, for those who have money to spend but believe that a courtyard is not the ideal place for them, villas and luxury apartments, with hotel-like services, remain the favorite choice for the affluent expats.

"If foreign families have children attending international school, they might prefer villas, as these usually have spacious living areas," Cai, of Joanna Real Estate, said. "They are also close to international schools.

"But if foreigners focus more on their work, they may choose apartments or serviced apartments that will offer a more convenient lifestyle."