Dust balls form on hard floors but you just don't see them on carpets IYSWIM? Moved from cold Victorian terrace (mainly carpet) with radiators to new build (not UK) with wooden floors & underfloor heating throughout. I noticed significant increase in dust etc but I think it's simply because it's "hidden" with carpets, urggh.
I read this thread with interest, I moved into a house 2 years ago with underfloor heating in the lower floor, the whole open plan area is divided into 3 zones and it throws up dust onto the surfaces when its on. So we have seen a real problem with dust with our underfloor heating. Rob