Pupils were left without heating after burglars caused damage during a raid on their school.
They interfered with the fuse board and heating during a break-in at Inglewood Junior School in Harraby, Carlisle.
Damage was also caused to two doors, said police. The children were left without heating during morning lessons.
Officers are appealing for witnesses who may have seen four teenagers in the grounds of the school and on its roof.
They were believed to be there between 9.50pm on Wednesday and 12.15am the next day.
A police spokesman said: "The group are believed to have been teenagers – three males and one female – wearing sport branded tops.
"One male was on a push bike."
Officers are appealing for information on 101.
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