FYI - If you have an electric dryer, you can divert the dryer exhaust inside the house during the winter. Don't do this with a gas dryer due to the CO2, CO, and other exciting fumes generated by the burning natural gas.
I installed a dryer heat diverter last winter and it definitely helps warm and humidify the house -
Winter Heat from a Clothes Dryer | EcoNewMexico.com. During the spring/summer/fall I flip the lever back to vent outside and I use our clothesline most of the time.
Tim