Full load of pretty good hardwoods last night at 10pm. Dropped to -10 here last night with who knows what wind chill. Woke up to house at 64 degrees at 5am. Furnace had good coal bed, but was at 159 degrees, with normal operating range 175-185. So not too bad based on the conditions I think. My furnace cannot keep domestic hot water and 5000 square ft at 70 degrees for 8 hours in anything below 25 degrees. Have just been periodically supplementing with electric heat to get it to 70 when we area awake.
