My 1 month old has continuing mucous and nasal congestion? Could it be the heat in house or formula?

My baby is always congested and sounds like he has phlegm in his thoat,(kinda like we do and need to clear our throat, but obviously they can't). I have humidifiers going day and night, and they really do not help. I've also tried regular, lactose free, and soy formula, trying to rule out allergy, and it seems to be the same with all. Has anybody experienced the same issues?