So i was down in the basement looking at the boiler since the thermostat was calling for heat and the pipes were cold. I noticed that the pump was hooked into a thermostat that was clamped to the feed pipe. It was set to turn on when the line temp reached
125 deg F.Is there a good way of calculating the best temperature for the feed?
The boiler is old and inefficient (I estimate the boiler is at least
50 years old), so i would think that getting the heat to the house quicker would result in a shorter boiler run time.We have several variables here.
1: cost of running the inefficient furnace 2: energy usage of the pump 3: efficiency of transfer of heat. (the 125F water in the pipes would trasnfer to the 60F room more efficiently than lower temp water since the diff in temperature is greater, yes? ) 4: thermal mass of the system 5: thermal mass of the house 6: air exchange rate for the house (I would say this is high) 7: insualtion in the house (extremely low) etc etc etci have no idea where to start on the heat calculation to find out if a lower pipe temp would save money.
My gut feeling is that running the lower temp water through the pipes longer will be more efficient since the boiler is *so* inefficient that anything to get the heat out faster would be better.
Other datapoints: Gas is about $12.71/MCF here electric is $0.0877 /kWh