How can you adequately heat your school while minimising energy waste?

Either on or off

The highest level of heating control in a school is whether the system is simply on or off (sometimes ‘winter’ or ‘summer’). Some schools will wait as long as possible to use any heating, while others may feel heating needs to be on sooner. Others have never switched the heating off and rely solely on the thermostat to determine when heating comes on.  What is the case in your school?

Heating set times

Besides on / off, heating is controlled with set times and target temperatures. Most schools set heating times to match when users are at the school. For example, heating only on weekdays just before users arrive and turning it off just before they leave for the day.   

Some schools may also choose to heat at certain points within the day – for example, turning the heating on for a short period in the morning and again around lunch – particularly in milder weather.

Other schools have never checked their heating set times or rely on a heating engineer to set these in September. When was the last time that your school checked the set times for heating?

If in the past you needed heating on for some evenings or weekends (e.g., for an evening class), a review of heating times may reveal that you are using more heating than is needed. Adjusting these times can cut your energy waste significantly. If someone at the school is able to check heating times weekly, adjusting as needed, potentially even more savings can be made.

Crucially, check your heating is not accidentally set to continuous, where any set times are ignored as this wastes 12 to 16 hours of heating per day (and the full 48 hours on weekends) – a huge amount of heating that isn’t needed which is costing your school money.

The thermostat and set temperature

Most school heating systems have one thermostat; you may or may not know where it is located.  The settings will include a ‘target’ temperature, such as 19 degrees.  Your heating will only switch off when it reaches (and remains at) this temperature.

However, if the thermostat is near an external door, draughts from the door may switch the heating on unintentionally.

Equally, if the thermostat is in an overheated or poorly heated area, the heating may switch on or off unexpectedly.  Try to locate your thermostat or ask a heating engineer where it is and check the temperature set point on your heating controls.

Radiators

Many schools with boilers have radiators, most of which will have a thermostatic radiator valve (TRV), usually labelled from 0 to 6. TRVs allow local control of heating, but do not override on / off, heating times, or target temperature.  TRVs can be set low in spaces of short-term use such as corridors and toilets. It is recommended that you set TRVs to medium in most other spaces.

If TRVs are left on high throughout the heating season, some energy waste may occur. To avoid this needless waste of heat and carbon, re-set TRVs regularly when possible.  Ideally (Covid-19 protocols notwithstanding), encourage staff and students to turn down TRVs first before opening windows when they are too hot.

Maintenance

All boilers will have regular scheduled maintenance to ensure function and safety.  However, these heating engineers can also make checks on efficiency. While there may be an additional cost, consider asking for checks on flue efficiency or burner efficiency. The age of your thermostat can also be a problem causing energy waste: if your thermostat is more than 4 or 5 years old, ask if this can be tested for accuracy as older temperature sensors can stray by 2 to 4 degrees, making a big difference to when your heating comes on.

Managing heating is not about being uncomfortable, it means ensuring heating is not accidentally on when the school is unoccupied and making best use of controls and settings. There are many small changes that can be made that save energy without breaking the bank.

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