If it is that cold out, I would let the cold air seep in and allow the room not to have any hear access. By doing this, you will make the room ourside and it will assist in the cold without being in the cold. You could also place a dehumidifier in the room which will allow you to make the room as dry as possible, however I still feel you will have an issue with condensation on the heat sinks of the units.
In the winter, if you leave your miner at home, it will heat the room and raise the temperature. the higher temperature will make the air less humid. You do not need a dehumidifier.