Why does our school heating come on too early in the morning?

Blog post by Claudia Towner

It is common in schools for the heating to come on too early in the morning. There are a couple of common reasons for this:

Problems with the optimum start control

Many schools have ‘optimum start control’ configured which looks at the outside and inside temperatures and automatically schedules the heating to start earlier in colder weather and later in milder weather.

Unfortunately, this does not work properly at most schools and is the cause of heating coming on too early, often before 4am. This can be due to boiler thermostats being positioned in draughty, hard to heat areas such as corridors or sports halls. As a result, the corridors or hall might come up to temperature by the time the school opens but the classrooms have wastefully been up to temperature since the middle of the night! We generally recommend, if this is the case, to turn ‘optimum start control’ off and try switching to fixed times e.g. 6.30am to 3.30pm and see how it goes.?Involve your pupils in?monitoring classroom temperatures?to help you monitor comfort levels.

Another issue with ‘optimum start control’ is that the time you set in the boiler controller is the ‘Occupancy time’ and not when you want the boiler to turn on. So, you should typically set it to 8:15am, on the basis that you want the school up to temperature for 8:15am and not, for example, 5:30am in the mistaken belief that this is when the boiler will come on. If you set it to 5:30am, all that will happen is that the ‘optimum start control’ will start the boiler earlier to get the school up to temperature for 5:30am!

Poor Thermostatic Control

For a school with good thermostatic control there should be a strong correlation between how cold it is outside and the daily consumption.?You can check this on Energy Sparks by comparing your gas or storage heater consumption with?degree days.

Poor thermostatic control can be due to

• a poorly located boiler thermostat e.g. in a hard to heat area such as a corridor, school hall
• windows being opened when the heating is on
• thermostatic radiator valves (TRVs) being poorly set
• communication problems between the thermostat and the boiler

To improve thermostatic control try to:

• move the central heating thermostat to a classroom or office
• if it is not possible to move the thermostat try setting the central thermostat to a lower temperature. Involve the pupils?monitoring classroom temperatures?to check temperatures are similar across the school.
• introduce a policy to prevent windows and doors being left open when the heating is on
• inspect thermostatic radiator valves on a weekly basis to check they have not been changed by pupils and staff

For more tips on how to get pupils involved in saving energy in your school this winter. See our two new heating programmes:

• Smart Schools Stay at 18 degrees | Energy Sparks
• Watch Out for Heating Waste! | Energy Sparks