Mould advice

Leaving the house heating off (your report, 22 November) in cold weather with no change in other activities like cooking and showering risks the development of black mould as humid air condenses on cold surfaces.

At least fit and use extract fans in kitchens and bathrooms to get rid of excess water vapour. However, a certain level of heating is required unless no water vapour is going to be generated. Try to keep the relative humidity below 70 per cent. STEUART CAMPBELL

Edinburgh