We often hear stories about how rental properties are cold and damp and indeed, some are. Dampness or high internal moisture levels can occur as a result of inadequate waterproofing and moisture coming in from the exterior, particularly in basement flats, but in some situations the high internal moisture levels are, at least in part, due to the way people live.

A significant source of internal moisture is as a result of normal household activities such as washing, bathing and cooking. Even our breathing releases some moisture into the air. While we obviously cannot stop breathing or eliminate all the household activities that generate moisture, some of the activities can be avoided and where this is not possible, the moisture can be removed or managed.

Keep your home as dry as possible

Dry air is much easier to heat than moist air. By preventing too much moisture from being generated indoors and by removing the moisture that is generated, the air will stay drier, be easier to heat and the indoor spaces will feel much more comfortable.

Prevent excess moisture being released indoors

The first step in preventing high levels of indoor moisture is, where possible, to avoid some activities. The primary generators of indoor moisture are drying clothes indoors and using unflued or portable gas heaters. An average load of washing can release up to 5 litres (an average plastic bucket) of water as moisture vapour and an unflued gas heater will produce around 0.5-1.0 litre of water per hour – this can amount to a substantial quantity of water vapour in one evening.

By not drying clothes inside unless there is good cross-flow ventilation from at least two opening windows on opposite sides of the room, and by not using unflued or portable gas heating, two major sources of indoor moisture will be eliminated.

Use mechanical ventilation if available!

The next step is to remove moisture as it is generated. If there is a rangehood over the stove, use it every time you cook, and if the bathroom has a ventilation system, use it every time you shower or bath. By removing generated moisture at source, the amount of moisture released indoors is significantly reduced.

Open windows

Finally, open windows whenever possible. In windy Wellington, we are blessed with a natural ventilation system. Air movement (wind) passing an open window will draw air, and the moisture contained in it, to the outside.

Tips to help keep your home dry inside

• If there is no mechanical ventilation in the bathroom, open a window after showering or bathing.
• Try to leave at least one window open during the day and leave all doors open, even patially to allow air movement right through the property.
• Sleep with a window open – people generate moisture from breathing while they are asleep so a window that is open will help remove the moisture to outside.
• If security is an issue, ask for security stays to be fitted on the windows you would like to be able to leave open.
• And don’t forget wardrobes and cupboards – leave doors open from time to time to air them and allow moisture to escape.