I have a central heating system with natural gas (atmospheric) heater warming the water going through the closed loop to radiators.
I can set the temperature of the hot water in a fairly broad range, 30-57C.
As I have added a thermostat which turns the heater on/off depeding on surrounding air temperature (set to 21C), I was wondering, if there was difference in efficiency (in terms of gas usage), depending on whether I set the heater temperature higher or lower.
Obviously, the lower I set the temperature, the slower the rooms will heat up, and the longer the heater will run. On the other hand, it will need to maintain lower temperature in the pipes, and probably burn less fuel that way.
Apart from keeping an eye on the gas meter for some time, (and interpreting the readings with adjustment for outside temperature), is there some way to figure out, what might be the best settings for using least gas, or even if it matters?