[RonSorino]

I am looking at a small red light blinking through the front pansl of my furnace... does that mean a filter change ?

[montyg]

I am looking at a small red light blinking thru the front pansl of my furnace...does that mean a filter change ?

No, this is probably a "code light" which gives you or the technician information as to how the unit is functioning. It should be flashing steadily slow or fast.

[Frdbrkl]

Filters should be changed monthly-not every 3 months like some filter mfrs say.

The little red LED is most likely indicating proper operation, unless you have a problem, in which case it will most likely shut down the system and give you a series of flashes in rhythm to display the error code. Error codes on Carrier furnaces are right inside the outer door torwards the bottom.