The air in the house can get very dry when the heater is running. The air passages need to stay moist in order to stay healthy. I highly recommend using some sort of vaporizer or humidifier throughout the night. When we travel, we will run the hot shower in the hotel room for a few minutes to get a little steam in the air. Also, leaving some water in the bathtub can provide a little extra moisture in the air. In the morning, be sure to open windows and let the rooms air out for a while, otherwise mold can start growing on the walls (I learned this the hard way…).
Humidifier Vs vaporizer? Hot Vs cold? Doesn’t really matter. There are some very nice units on the market that can give both warm or cold mist, these are great. I have usually just used the cheap $15 units that give a warm steam and they have been fine. You need to be careful with these because the steam can burn.