What is the effect of the increase in branches on the surface area of the alkanes, and thus the effect on the trend of the boiling point of alkane series?

What is the effect of the increase in branches on the surface area of the alkanes, and thus the effect on the trend of the boiling point of alkane series?
2) Will the increase in the same number of identical branch(es) bring along the same change in boiling point in simple alkane series?
3) Is there a trend for the effect of number of branches on the boiling point of alkanes with different number of carbons?