Yep, water needs could definitely increase given that the room will be dry to start with and the warmed air coming up to them will be even drier. Like many have said already, you can simply read that in the soil and the plant and adjust to maintain proper, but not too-wet, moisture levels. A "heat wave" coming up could also be a concern, one watering wouldn't fully correct, in which case it might need to be somehow deflected.
Light will likely be another issue for you with the shorter days at your latitude. At 49 degrees north (roughly Vancouver BC) day length drops as low as just over 8 hours in December. If your plants will be keeping sufficiently warm, they won't necessary go dormant and as the days become shorter and the light weaker it can lead to weak, stretched plants. I'd consider adding at least a small grow light above the plants to extend their "days" to healthy levels.
Good luck!