Generally, schools need heating from mid-October to early April but often their heating season is much longer mainly because schools forget to turn the heating off in milder weather. If the heating is left on in milder weather, classrooms get too hot, and windows are opened, rather than radiators being turned off, to compensate. The heating season should be significantly shorter at school than at home as 30 pupils in a classroom generate several radiators’ worth of heat. As a result, once the school is open, there should be sufficient ‘internal gains’ to keep a classroom warm without heating in all but cold weather.
Heating in schools only needs to be on between 85 days (south west of England) and 110 days (far north of Scotland) per year. How many days did your school leave its heating on last year? Energy Spark's seasonal control analysis will tell you.
Improving this is not always straightforward:
Asking your caretaker or building manager to be proactive at switching off the heating during milder weather works in many schools and is probably the best approach
In milder weather, some building managers change the boiler timings to run for a couple hours only in the morning before the school opens
Some boiler controllers have a setting, often called ‘day time setback,’ which will turn the heating off when the outside temperature is above a certain level e.g. 14C