Room faces east. I agree that the issue is probably our respiration. We don't have a vent in the room and probably need to do this sooner rather than later.
Why don't you have a vent in the room - was it once served with a fireplace which has been blocked up?
A vent with an areas of 6500 square mm is legally required in every habitable room, unless there's been a recent revision to Part F.
A vent should be sited to avoid becoming blocked by furniture.
http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,1647,en.pdf
P.5
DWELLINGS
Habitable Rooms
1.5 In a habitable room other than a utility
room, a kitchen or a room containing a kitchen, the
following provision for ventilation should be
adequate:
(a) a ventilation opening suitable for background
ventilation having a total area not less than
6500 mm2, and
(b) a ventilation opening suitable for rapid
ventilation having a total area of at least 1/20th
of the floor area of the room.
1.6 If ventilation is through another
You have a severe problem you want to address.
You should first heat the air in the room every day.
This will help absorb internal moisture into the air.
Then open the windows and try for cross ventilation across the dwelling - if you can't get this at least open every window in the place for a good thirty - sixty minutes.
Make an attempt to full air the house on a Saturday or Sunday.
A cold dry day is the best because there will be less moisture in the air.
My good lady wife has just pointed out that this will waste heat, but until the problem becomes manageable I'd try it this way.
When things get manageable you can open the windows for an hour and then heat the house.
This only deals with the symptoms.
You may find the underlying causes centre on inadequate or missing insulation in the roof, walls or floor, exacerbated by cold bridges at the window reveals.
You may also need to upgrade your windows and install additional insulation to your walls, but that requires specialist advice and is costly.
Proceed one step at a time and evaluate the results if you want to minimize costs.
You could do worse than give Eamon Markey at Dampco a call;-
There are a lot of other companies out there, but it is important that whatever advice you get you inspect properly and check the ventilation and insulation are both adequate and appropriate.
I cannot recommend dealing with damp problems by first applying chemicals to the surfaces affected. Chemical or surface treatment should be a last resort. Remove or address the cause first. However, some prime cause remedies may be costly. It may be cheaper to use another method.
As per normal, advice given in this forum is remote from the action, isn't exhaustive nor is it expert. Consult a professional.
FWIW
ONQ.