L.M.
They dryness could be caused by a Vitamin A or Vitamin B2 deficiency. Some conditions cause people not to absorb their nutrients very well. Cold, dry weather also causes chapped lips. Your house does sound a little cold. Maybe that's just my opinion! :) It could also be a food allergy or intolerance. I get very chapped, cracked lips from wheat (gluten) and dairy.
Here is an article on food allergies to get you started: http://www.healthwatchcenter.com/2007/11/most-common-food...
Take care!