Damp from within in some properties is probably a common problem and will be getting increasingly worse with increases to energy prices. Often for compact homes such as a one bed flat with one or two occupants, Landlords need to ensure tenants heat their homes enough to prevent condensation on walls and ventilate the rooms enough to clear moisture laden air which results from normal home living. The problem in some cases is the level minimum of warmth an occupant needs in all rooms is probably lower than the temperature needed to keep walls and windows warm enough to prevent condensation forming. For example the hall, kitchen and bathroom may be quite cool most of the time and only the living room is warm.
Compounding this problem is the belief that drafts needed to stopped completely to save energy. This includes blocking up of building vents, not opening windows or not even leaving windows locked on a vent position.
Add to this the occasional drying of washing indoors which again increases the moisture in the air once more.
Modern energy saving and new building techniques are introducing the idea of gentle continuous forced ventilation but with heat recovery from the exhaust air. I’ll guess these solutions are a) not cheap and b) will not easily fit into a compact flat.
Tenants should be told in advance as what costs they will need to expend on energy to maintain the rented home in good condition. They need to factor this into their afford-ability calculations.
Instructions on how to use the ventilation and heating should be provided. Don’t forget that old fashioned opening of windows, or even the back door, for a few minutes is a perfectly good way of achieving a quick complete air change in a room in a short enough time that the walls and and fittings will not loss too much heat.
Landlords could include in the inventory or as an optional extra a dehumidifier such as this http://www.dehumidifiersuk.com/c/265286/1/desiccant-dehumidifiers.html with instruction (not just instructions). Dehumidifiers such as these use energy to operate but the energy turns into heat, which in turn usefully heats the home. A small one can keep say three rooms dry if all the internal doors are left open. They are not noisy either, depending on model. Maybe try Which or the web for reviews. Personally I would avoid the compressor type as there don’t work so well in colder rooms.
Finally, and I am not sure if this is already covered, young tenants in a first home may not have yet learned how to maintain a property. They may not have noticed how a home owner they last lived with used wipe down the windows and bathroom tiles regularly in the winter. Remember spring cleaning of homes, it is still necessary.
It is not just the new and young home dweller who may have mould problems in their homes. For example I have seen it recently with the elderly as well, in rooms that are not heated to save money. An installed wall mounted model with a humidistat may help here.
I intend to find out more about these newish forced background ventilation systems with heat recovery that are being offered under the energy efficiency banner. If I like what I see then I’ll report it here.