Otago District Health Board property services manager Warren Taylor said the $460,000 project to replace the towers on the top of the hospital's ward block was necessary because the existing units were about 30 years old and getting beyond their useful life.
It was essential expenditure for the health of the building and those in it, but the existence of the towers would not usually be something people would be aware of, he said.
They were used to rid the ward block of excess heat including that caused by clinical machines, and kitchen cool rooms.
Such heat could not be recycled within the building because of the risk of infection.
The fibreglass towers were more energy efficient and would be much easier to clean than the existing wood-slatted ones.
Mr Taylor said the new towers, which should be in place by late August, were being installed during the winter because they were not all needed during cooler months.
