If you aren’t already thinking about getting your home warm and healthy for winter, now’s the time to start.
Every winter we hear and see stories of people living in extremely damp, mouldy conditions.
It’s a symptom of living in older wooden houses in a temperate climate with inadequate heating, ventilation and insulation. However, it isn’t just extreme cases that need to be fixed — most of us would be more comfortable if we reduced the dampness in our homes.
A damp home is an unhealthy home, there’s no argument there. But it isn’t just that — damp air takes more energy to heat than dry air, so it literally pays to remove moisture from your home.
Musty smells, mouldy walls and ceilings, weeping windows and damp clothes in wardrobes are all signs you need to reduce moisture and increase ventilation or heating.
Start by reducing dampness sources. Moisture gets into your home in many ways. One of the biggest sources is moisture evaporating up from the ground through your floors (as much as 40L per day per 100m2). Check for dampness under your house and fix any drainage, guttering, downpipe or plumbing problems — then consider installing a sealed moisture control sheet.
Other daily activities can add moisture to your home: ![Use pot lids when cooking to contain steam and a kitchen rangehood or fan that vents outside.]
|Showers and baths||1.5/day (per person)|
|Clothes drying (unvented)||5.0/load|
|Gas heater (unflued)||Up to 1.0/hr|
|Breathing, Active||0.2/hr per person|
|Breathing, Asleep||0.02/hr per person|
|Perspiration||0.03/hr per person|
|Pot plants||As much as you give them|
Once the main sources of dampness are removed or reduced, you can think about ventilation. Just living and breathing adds moisture into the home, and we can’t stop doing that. However, we can open windows to let a breeze through and vent moisture-laden air. It seems counter-intuitive to open windows on a cold winter day, but removing moisture will be healthier and make your heating more efficient. Get in the habit of airing your home every day or leaving windows slightly open.
Many of these tips are free or low-cost, but they can be highly effective. Further options start to get pricier.
You could consider a dehumidifier to target parts of the home that don’t get enough airflow and remain damp. However, they aren’t a magic bullet — the best dehumidifiers in our tests remove up to 9L per day at 12°C, but only desiccant models perform when it’s colder. They are effective at drying smaller spaces, and act as a small heater too (they put out about 300 to 400W of heat).
Mould is known to cause inflammation, allergies and infections.
It is a relatively straightforward process to remove mould from hard non-porous surfaces, such as glass or ceramic tile. However, removing mould from porous substances such as wallboard, wood and carpets is more difficult and more hazardous. This is because spores can be released when disturbing rotten material, which can cause inflammation, allergies and infections.
In new buildings, some moisture is trapped during the construction process. Wet timber may also have been used. The sequencing and timing of the construction process is important to avoid this and be sure to avoid storing construction materials out in the open where possible.
To prevent damp air from building up under the floor:
Let moist air out and dry air in by:
This page was put together with the help of BRANZ.