[bluGill]

In a modern house insulation is very good (in general) and so your heating cooling expenses are not that high over a lifetime.

[Markoff]

So you are telling me cooling down or heating bigger volume of air takes same amount of energy/money than smaller volume?

[bluGill]

The larger use of energy in HVAC is recovery from losses from convection, conduction, radiation, and air leaks. The one time heating or cooling is small.