Higher electricity bills and finding the cash for staff pay is still a worry for a school with a million-pound buffer, its head teacher has said.
Ysgol Friars, in Bangor, Gwynedd, carried over £974,000 from last year as figures show the pandemic left school reserves up across Wales.
One union called the figures a "smoke screen" because most reserves are ring-fenced for specific projects.
The Welsh government said it recognised the pressure on public services.
A recent survey of head teachers has suggested pressures on school budgets could mean staff cuts across Wales.
The head of Ysgol Friars, Neil Foden, said the 1,400-pupil secondary school had seen its electricity bill double.
