He may already own the Iron Ballusters and would need to purchase the wood ballusters. Virgil is correct, wood railings and ballusters are a totally different installation than wood railing and iron ballisters. And that is not counting the finishing. The iron ballusters probably come to him already finished so their may be additional expense with site finishing of the wood product. Just because a product may be less expensive to purchase in a raw unfinished and uninstalled state does not make it cheaper in the overall picture. Plus many builders charge a "change order" fee which would affect the price as well. This is of course all supposition on our parts and the only way to find out the truth is to ask and hopefully he will be honest with you in his response.

I have iron. I really dislike wooden spindles. The only ones that don't make me cringe just a little bit are painted ones, and then what's the point of them being wood anyway? Even for outdoor applications like railings and decks I prefer the iron to wood - especially for outdoor, becaise I've had to hand stain over 400 wooden spindles before... yikes! In my area metal spindles are the standard for higher end homes, and oak are the standard for mid-grade. With metal ones, it's popular to mix spindle styles - e.g. have a few plain, then one with a scroll design, then plain... I hate that too. I went with all plan. Actually I'm not sure they're iron, but they're metal, and have a bit of finish. They aren't dusting nightmares at all. On the dust front, they're probably one of the more forgiving things in the house. DH just gets them with a swiffer or dusting attachment when he vacuums the stair treads. Our last house had wooden ones. That's how I know I hate them. :) Over time they got a bit shabby, which I don't think the metal ones will (lot easier to gouge wood than dent metal). This is such a completely subjective preference, though! Here are mine, though you can't see much of them. (Drywall dust forgiven, this was during construction still): This is NOT my house, but it's an example of the mixed spindles I was referring to. Notice the plain, then the one with the little knuckle thing, then 2 more plain, then scrolly... like someone couldn't make up their mind):

My guess is that the hollow ones would tend to be more decorative rather than being used for a functional railing. I have a decorative fence in my garden that has hollow balusters, but the wrought iron railing we used for our front fence came from a deck railing and it is solid iron If it were me, and I was using them for a staircase, I'd choose the solid for safety reasons.

Okay???