My boiler was set to heat my radiators to 75 degrees. When I had my annual check done, the engineer said it should be set to 60 degrees because that is a more efficient temperature.
What I don’t understand is why is that more efficient in the long run. Yes, the water is heated to a lower temp saving fuel, but now I have to run the heating for longer to get the house warm. Does having the heating on for longer not just cancel about any benefit from lowering the flow temp?