Ventilating your home
It is important to keep your home adequately ventilated - to maintain air quality and remove moisture for a healthy indoor environment.
As we improve air tightness, our homes are becoming easier to heat. However this improved air tightness means it's even more important to make sure you have good ventilation.
How to ventilate your home
Make ventilation part of your daily routine
The simplest and cheapest way to ventilate your home is to open doors and windows regularly to allow fresh air from outside into your home.
In summer, open windows and doors in different parts of your home to create a cross-draught, which will circulate air and help keep your house cool.
In winter, air your house at least once a day for a few minutes with wide open doors and windows to create a cross-draught. This will quickly replace stale indoor air with fresh outdoor air.
Because warm air can absorb more moisture than cold air, ventilation will remove moisture from everyday living most effectively when your home is also heated properly. Learn more about heating your home.
Warm inside air can hold a lot of moisture, which will form condensation as it cools unless it is removed from the house.
To avoid condensation problems, ventilate when you turn off the heating - for example, before you leave the house in the morning and just before you go to bed at night.
Ventilate overnight
Ventilating your bedroom overnight is also important for maintaining air quality and reducing the risk of excessive moisture and mould growth. You can keep a window slightly ajar on a hinge. Fit security latches if the window could be used to enter the house.
Sort your bathroom, kitchen and laundry ventilation
Ensure that there is effective ventilation in wet areas in the home (such as the bathroom, laundry and kitchen) to minimise the moisture that causes the problems. Install an externally vented range hood or extractor fan over your cooker, an externally vented extractor fan in your shower/bathroom and exhaust laundry dryers to the outside.
Extractor fans need to be sized and located properly for the size and type of room - ask your supplier for advice on this. Leaving the bathroom window open allows air flow into the bathroom and will improve the extractor fan's effectiveness. After a shower, let the fan run for a few more minutes. Clean your extractor fans regularly to maintain their performance.
Home ventilation systems
Home ventilation systems use fans to move air into the house and can provide an alternative to opening doors and windows, provided the model you choose is well designed and installed. The performance of ventilation systems can vary widely depending on a range of factors including the type of system and how well it is installed, your type of house and the climate.
Home ventilation systems are not a good solution for fixing cold and dampness problems in homes. If dampness is your main concern, then address the source of the moisture problem first, before looking at ventilation systems.
A ventilation system is not an effective home heating solution. University of Otago research shows that the heat available from moving roof space air into your home (as the most common type of ventilation system does) doesn't provide significant heating benefits compared with what you need to properly heat a home in winter. The research recommends that people don't install this type of system for heating purposes. Read the Otago University research report.
If you want to make your home warmer, sort out your insulation and install an efficient heating system.
Learn more about home ventilation systems.
Dampness, insulation and heating
A cold and damp house won't be improved by ventilation alone. You need to think about insulation and heating as well as fixing sources of excessive moisture.
Have a look at the sections on this website about insulation, heating and tackling dampness for more details.
