12 May 2024
Hot Water Preheat function on a Combi Boiler
The pre-heat function on a boiler is designed to ensure that hot water is ready to flow to the taps at a moment’s notice.
It means the boiler always keeps a small amount of water hot.
It is a handy function when you want to wash your hands and do not want to wait for water to heat up, but it also means that the boiler is heating up water when you do not need it.
However over the course of a year this can really add up! An untimed pre-heat has been found to use about 5-10% of the average household's gas bill.
Is there another name for this?
Another name for this function is “Comfort mode” and “Eco button on/off”