Load is a term used for the amount of heating or cooling your home needs. Thirty years ago oil and gas were cheaper and people were less concerned with efficiency. The average boiler was only 50-60% efficient and 2-3 times too big. Older units are still extremely inefficient; however, the heating systems manufactured today are 80-95% efficient. No matter how efficient the unit, if it is sized incorrectly for your home, it still uses more fuel than needed. That is why salesmen run load calculations. Actually, you should welcome this. Finding out that your heating system is only 50% efficient and three times the size it should be will allow you to realize big savings in the amount you spend each year to heat your home.