Have you got old radiators? Our looked really clean when we moved in, when we put the heating on the dust level almost doubled. I managed to look inside and underneath, they were gross. Caked in dust. Igot one of those radiator dusters and that helped, but the best (yet messy) solution was using a hairdryer to blow in and around it. You should have seen what came out - it was Household sporn worthy
Also, carpets and our brushed cotton sheets have contributed.
We have the old fashioned radiators, we like the look of them but yes they are dust collectors. I haven't noticed more dust when they're on though! We have a wood burner too so really we have no hope for a dust free house. Lovely and cosy though!!