The heating system in some areas of Ninewells Hospital will be shut down until tomorrow afternoon to make way for emergency repairs.
The work will be done in phases overnight and into tomorrow. It is expected to be fully operational across the hospital by the afternoon of February 15.
Additional heaters will be placed to fight any chill.
A NHS Tayside statement said: “Patients should be assured that all of our services continue to run as normal and no procedures or outpatient appointments have been cancelled.
“Nursing staff have been informing patients and their families about the arrangements ahead of the repair and they will be on hand to answer any questions.
“NHS Tayside would like to thank patients and their families for their understanding.”