How to dehumidify a Bedroom?

26th Feb 2019 | |

How to dehumidify a bedroom:

It’s that cold time of year when we receive numerous calls about mould and condensation issues, particularly in bedrooms.  We also seem to have been dealing with quite a few damp external walls from gutter leaks and penetrating damp, and there seem to be leaking en-suite bathrooms quite a bit too!

We would offer a few thoughts on drying bedrooms as follows.

  • Condensation is caused by humidity coming into contact with a cold surface where, if the dew point is met, moisture will form. Typically this can happen lower down on walls, where warmth doesn’t circulate, and behind furniture/curtains where air turnover is low.  Some indicators to look out for would be patches of paint darkening; mould spots appearing; or more obviously water may be running down cold window panes at times.
  • Condensation can be remedied with the use of a dehumidifier, which lowers humidity in bedrooms and therefore reduces the opportunity for condensation to form. For general condensation control over a long period of time, we would usually recommend a domestic-type machine with a capacity of around 20L per day extraction rate.
  • The cost of running a dehumidifier should be weighed up against the cost of more ‘natural’ methods such as heating and ventilating the room.
  • We would note that ventilation in a bedroom would assist with lowering humidity, particularly for example leaving window vents open as much as possible. In addition, heating will help raise wall temperatures and reduce the likelihood of condensation forming.
  • Penetrating dampness in a solid external wall can be difficult to dry out in bedrooms, particularly because it is not advisable to leave a machine running constantly overnight when the bedroom may be used.  We would often with solid walls recommend stripping back render/plaster in order to expose the structural materials to the full benefit of dry air from the equipment.  Whilst this is intrusive work, it can often be more cost-effective overall because of the time saved in drying.
  • Speeding up evaporation of moisture from walls can be achieved with the use of an industrial fan, directing airflow over the affected wall area. Heat also helps, so the addition of heating would be advisable, with temperatures in mid-20 celcius range being beneficial.
  • Bathroom overflow leaks are another typical cause of water damage in bedrooms, often leading to wet carpets. Equipment we would typically use for drying floors would be an industrial dehumidifier plus one or two fans to circulate dry air around the floor level.
  • For wet floors, it would often be recommended that carpets/laminate and underlay be removed, in order to full dry the structural material underneath. Attention needs to be paid also to whether water may be trapped behind skirting boards, and the possible need to remove skirting boards in order to allow drying of the walls behind.


For any advice on humidity, water damage or damp levels in your home or commercial property, please contact us on 020 7760 7660 or