They are the modern-day "desert" lands of Singapore. Miles and miles of lifeless back alleys behind shophouses crammed with unsightly air-conditioning units which can ramp up the temperature to 50 deg C.
But these lanes - a familiar sight in places like Duxton, Rochor and Jalan Besar - could come alive with alfresco dining and tree-lined walking paths if an ambitious idea to remove these units is adopted by the authorities.
The Future Cities Laboratory (FCL) - a research centre jointly established by the National Research Foundation and the Swiss Federal Institute of Technology - is proposing integrating multiple air-con condensing units into single units on top of shophouse rooftops.
This would eliminate the hot and noisy split units from alleys, freeing them up for uses other than goods delivery access.
The Straits Times understands that the Urban Redevelopment Authority (URA) has contacted the FCL to find out more about its research, which will be on display until the end of the year in the Create Tower within the National University of Singapore.
It is part of a larger study the FCL is conducting in the Rochor area, to analyse its urban use and identify changes in the neighbourhood.
The URA did not comment further.
Conservation guidelines state that condensing units are to be situated at the rear of shophouses. For example, they "can be neatly or compactly placed at the rear and lined along the parapet, party walls or rear service block walls".
This strict requirement to protect the authenticity of historic shophouse facades makes the problem more extreme in Singapore.
Researcher Marcel Bruelisauer said many back alleys are lined by shophouse rears of "just a blank wall without a single window, and many split units". He added: "It destroys opportunities to make them into more vibrant spaces."
Shophouse tenants would also benefit from reduced air-conditioning bills if the split units are integrated. "Clustering of split units heats the alleys up and the air-cons have to work harder to deliver the same amount of cooling," he said.
The researchers have recorded temperatures of up to 50 deg C at split units in back alleys.
They presented their work on Tuesday at the Sustainable Building Singapore conference at Marina Bay Sands.
"This has not been done before elsewhere in the world," said Mr Bruelisauer. "The technology already exists. None of this is rocket science."