Is there anything that gets "roughed in" for AC that can't be done later without a lot of work?

We're building a new house, and don't plan to have AC. We don't have it in our current house, and we've never felt the need to spend the money putting it in. It doesn't get that hot for more than a couple of weeks per year. And it cools down so much at night, sleeping is very rarely a problem.

The new house has extra insulation, and we've done solar modelling to reduce heat gain in the summer. But we've had a half a dozen people tell us that because we'll be south facing, and have a 3rd floor, that we'll "need" AC. But they aren't people who are aware of the extra efforts we've made to reduce energy consumption in this house. And the current house is also south facing. The comments aren't all coming from HVAC installers, either. We're going to live in it at least a year before putting the AC in.

In a previous house, in a different city with hot summers, we had AC put into an older house. I don't think AC existed when that old furnace was put in. But it wasn't that big a deal to retrofit it. I don't know the details of what was involved, but it didn't costs us much money.

So, is there any savings to putting in the rough in that the HVAC guys are pushing? Or are we just spending now what we can put off for later, or maybe not need to spend at all?

We're putting in pipes for radiant heat in the basement, but might never buy a boiler. But it's something that if we decide to add later, it would require jackhammering up a lot of concrete. So in that case, roughing it in "just in case" makes some sense.