Adjust your system regular boiler flow temperature for increased efficiency

Adjusting the flow temperature for a system boiler or regular boiler is different to a combi boiler. When you have a hot water cylinder, normally you set it to 55 degrees or 60 degrees on the thermostat to prevent legionella formation. When you set to these temps, the boiler flow temp must be higher in order to heat the cylinder and satisfy the cylinder stat, otherwise the boiler would not stop firing until the timer turns it off and the cylinder would never reach it’s intended temperature.

It is therefore suggested to change to a flow temp of 65 degrees at the boiler in order to maintain a difference of approx 5-10 degrees. If the difference is smaller, the time taken to reheat the water is longer.

If you have advance controls these can automatically have different flow temperatures for the hot water cylinder and heating. The usual advanced setup is called priority hot water setup. This is outside the scope for this page. Please contact us for more information on this, alternatively we will create an article on priority hot water.

Combi Boiler Condensing savings calculator

Select your boiler below to adjust the flow temperature.


BrandModels / FamilyBoiler TypeVideo
VaillantEcotec Plus/ Exclusive Post 2012System / RegularVideo

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