Q Loss (BTUs) = Surface area x (indoor - outdoor design temp) / Effective R-value*
*You have to take thermal bridging through studs into consideration - an R12 wall has a real thermal resistance value of less than R12.
The R value of basic wood double pane windows is around 1.7 if I remember correctly.
For air leakage:
Q sensible (Btus) = 1.09 x airflow CFMs x (indoor - outdoor design temp)
A blower door test is required to measure leakage.
I don't know the formula for latent heat loss off the top of my head.
Don't worry about passive solar heat gain for heating since the system has to be sized for design conditions. (No sunlight)
For making a template I recommend excel.
General public's attitude towards our energy predicament: "I reject the reality of finite resource depletion and substitute it with my own; energy is infinite, we just need an alternative storage medium to run the cars on. The economy can grow indefinitely - we just need to "green" everything! Technology is energy! Peak what?"