Increasing humidity?

I have a Quadrafire Expedition 2 insert in my house. My house is a 1971 colonial in Southern New England. Now that we have new windows, the heat is being held in much better but it’s drying out the house like crazy. How do people keep moisture levels up in houses without:

1. Whole house humidifiers
2. The ability to put a cast iron pot with water on the stove (ours does not have any horizontal surface to put a pot on)