Reduce Excess Moisture in Your Home


Tackling dampness and ventilation creates a dry, healthy home that holds in the heat, reduces emissions and keeps money in your pocket.

  • Air your home regularly. Open doors and windows for 10-15 minutes each morning, or use a ventilation system. Airing out a room when you turn off the heater also helps to avoid condensation.
  • Use energy efficient, low emissions heaters. Heat every room being used by someone to at least 18°C. Don't use unflued or portable gas heaters.
  • Dry washing outside. Use a washing line or rack under a covered verandah, garage or carport. Use a clothes dryer only to finish them off, or if it's raining.
  • Use extractor fans and rangehoods. Make sure they're big enough to do the job, regularly cleaned and send air to the outside, not your ceiling space.
  • Turn on the bathroom fan before a shower or bath. Shut the door and open the window an inch. Afterwards, leave the fan running until the moisture clears.
  • Use lids on pots when you cook. This helps to stop the steam escaping.
  • Move furniture away from walls in winter. A 10cm gap will discourage mould (especially on external walls).
  • Leave wardrobes slightly open. A little air circulation discourages mould growing on fabric.
  • Use a dehumidifier on damp days. This will help to reduce condensation but it won't solve a dampness problem. It's better to tackle the sources of damp and heat and ventilate your home.

  • Extractor fans, rangehood and clothes dryer are sending air and moisture to the outside, not inside or in the ceiling space. Extractor fans and rangehood filters are clean.
  • Extractor fans and ducting are at least 150mm diameter (smaller ones won’t be effective, except in a toilet) and ducting isn't damaged, and is short and as straight as possible.
  • Plumbing pipes and services have no leaks and no moisture is getting into walls, floors or near showers or baths — get under the house if you can.
  • Downpipes and gutters are clear and not leaking, and downpipes connect to storm water drains — check in the next downpour.
  • Subfloor wall vents are unblocked and the subfloor area is clear.
  • Wall and roof cladding, and flashings have no leaks.
  • Concrete walls and floors have no damp patches or white mineral deposits which indicate moisture is coming through (lift the flooring to check).

  • Bathroom extractor fan — install a run-on timer switch to keep the fan running for a few minutes after you switch it off, or a humidity sensor to turn on the fan when it detects steam.
  • Install a shower dome — to stop steam escaping into your bathroom.
  • Buy a bed base — if your mattress is on the floor, a bed base will let air circulate underneath.
  • Improve drainage — if surface water flows under your house during heavy rain, reshape the outside levels or install drainage. Ask a licensed drain layer for advice.
  • Install ventilation system — A heat recovery/ventilation system brings outside air into the house while recovering the existing heat via a heat exchanger. This allows the house to be fully ventilated without throwing away valuable heat that has already been paid for.
  • Seal damp concrete or masonry — use a waterproofing sealant or moisture barrier. Ask an expert about the best product for your situation.