So in my current 2800ft SFH I have a dual zone system that includes 2 completely seperate systems(one in the attic and one in the basement).

Now I'm looking to build a new home and found a builder and house we like. The house only comes with a single system(a/c + propane heat). When I asked the real estate agent for Stanley Homes he said they now design the house to work best with a 1 zone system...when I pressed him on it he didn't really seem like he knew what he was talking about. They do have an option for $2k where I can add multiple zones using baffles to the single system. My question is, is that going to hurt or help me? Aren't I going to be taking a system that is designed for say 3000 square feet and cutting it's airflow by 1/2. Is it going to work less efficiently than just letting it blow through the whole house?

Thanks for the help!