Hot water supplied by gas boilers is surprisingly inefficient in schools. On average, schools on Energy Sparks are only 15% efficient at providing hot water. This is because, in order to deliver water quickly to taps, hot water is continuously circulating on a network around the school called a ‘circulatory hot water system.’ Even if this network is well insulated, it is continuously losing heat. As a result, the gas used to heat hot water is very inefficient. On average, heating hot water consumes 40% of a school’s overall gas consumption.
A short term solution is to ensure that the hot water is only circulating during the school day and is turned off out of hours, at weekends and during holidays (subject to Legionella flushing at the end of long holidays).
A long term solution, and one which is much better for the climate, is to remove the circulatory hot water system altogether, replacing it with point of use electric hot water heaters. This is often best done on a gradual basis over a number of years e.g. as toilets are refurbished.
Energy Sparks provide estimates of the efficiency of your hot water system and the benefits and costs of making changes to it.