No offense but orbs can also be caused by light refraction on dust particles.
I'm no expert so whose to say your orbs may be true orbs or may just dust particles. Just thought I'd add my info on the dust particle thing.

As for my opinions on ghosts... I do believe, but I have rules... Don't show yourself to me. Do not talk to me. Do not move stuff... especially if I can see it move. Basically DO NOT scare me. We'll get on just fine.

The movie The Others really changed my thinking on things. Great movie if you haven't seen it.