how do you put a price on IAQ?
The same way you do by what works and what the homeowner can afford.
as far as cleaning it, all you need is a vacuum cleaner. that should be a common house hold item
How far can you push your sweeper hose into a duct? Better yet will it fit thru a vent opening and how do you get all of the top, bottom and sides of something you can't see into?
am not "lumping" you into any category.
you said: "you're simply living off thier fear to make more money IMO" You won't find me telling scary stores of mold or dust mites, yet I know many hvac contractors who use fear to sell new systems - it will cost them more to fix it than replace it or dream up unneeded repairs to sell a new one when little to nothing is wrong with the old one!
as far as duct cleaning goes, if the duct is that dirty, it needs to be replaced. plain and simple IMO
I'm guessing then that in your area all of the ductwork is in the attic and not behind walls or in floor joist areas. That isn't true here and if its not in your area please tell me how you replace those with tearing half the house apart?
and FCS brings up a good point about construction debris, but a responsible contractor would and should have a sealed duct system until system start up. i know we mechanically seal duct systems until start up.
Winters get cold here and I can't speak for all, but we clean many brand new homes simply because the contractor ran the system while the home was under construction. We also clean many older homes because the remodeling contractor did the same or the homeowner actually wanted to live there while the work was being done!
besides that, what's the average age of the duct system being cleaned? chances are it's leaking more than it is dirty, and in the case of a leaking duct system, a new duct system will improve IAQ much better than cleaning it out.
From brand new to very old and once again how do you install a new system where the old one is behind finished surfaces? We are seeing far more thermopan and flex duct in newer homes and remodeling work and few contractors take the time to seal this around pipe openings, etc. Even less seem to know how to install flex duct properly and we find a lot of systems where the filters don't fit properly.