vent noise

we bought a house this summer, when I turned on the air conditioner in upstairs, I heard a little noisy from the vent. right now, when I open the heater, the noise seems to be much louder, which sometimes makes me wake up at the midnight when heater is working.

does anyone know how it is going on, and can it be fixed? or I just change the filter, because I have not replaced the filter since we moved in for several months.

if it needs to be fixed, we do have home transfered warrentee, can it cover the fixing fee?

thanks a millon for any relay.