We have scheduled to replace the flues in the gas boilers as a pressure test and CCTV test have revealed there are leaks and gaps which is causing inefficiency. The flue will now be double skinned to improved energy efficiency and ensures that heat gets around the building better - we should also therefore see an improvement in boiler operation and will not have to have them on so long to heat the school.
This should result in a lower utility use and cost, improving energy efficiency for the school (and making sure everyone is warm, more importantly!)