If you are not warm enough, have more coal on hand, and here is a simple solution and requires no analysis: Crank it up, or get a bigger rig to crank up. The two holer will be damned chilly if the wind is blowing through it, too
ALWAYS have an extra supply on hand or real handy. If you live by the degree days and you are an oil dealer, you will be crying or smiling from day to day. IF you are a propane dealer, the KY stays warmer with fewer degree days, more, it's a thermal shock....... This AIN"T rocket science....even though a few of you think so.
Understand what 'Steam-up' mentions, that all things are not equal in making the formula appear as a linear projection. If it's colder than normal, you will use more btu's from whatever source. Wind chill may not be technically a true form of heat loss, but anyone who has been on a hilltop or a frozen lake with 30 mph winds will surely disagree.
) doesn't hurt much, but 10 degrees and 40MPH winds KILLS!!!! Anyone Iceboat? Try that one for a chilly, bumpy, ride!