Beacon

Achieving a healthy indoor environment is all about balancing temperature, the moisture levels in the home (relative humidity) and ventilation. 

When even one of these factors is out of balance, it affects the other two.  For example: Many of our newer homes are tightly sealed, which restricts air movement, traps moisture and toxins inside, and encourages overheating in summer. While a well-sealed home is important to keep the heat in, a healthy indoor environment will have options to allow air to circulate.

The first step: warm in winter, cool in summer

On average we spend 75% or more of our time at home.  Yet New Zealand homes are too cold and damp: the World Health Organisation recommends that the minimum temperatures for good health are 18ºC for living areas and 16°C for bathrooms.  New Zealand’s homes are often below this.

A healthier home is warm in winter, cool in summer.  To maintain comfortable, healthy temperatures in winter, we recommend starting with insulation.
Insulation is all about maintaining an even temperature in your home. It works by creating a barrier that slows the transfer of heat from the inside to the outside of a house.

Without insulation, heat escapes from your roof (42%), floor (10%) and walls (24%).     To keep your house warm you are heating far more air than you need as much of it is heading straight outside.  Insulation means your heater, pellet fire, wood burner or other heat source will warm your home much more efficiently.

Insulation is also effective for controlling overheating, particularly ceiling insulation which reduces the amount of radiant heat absorbed into the home through the roof by buffering the ceiling cavity from the rooms below.

A warm house is also drier

Cold air holds far less moisture than warm air.  In cold temperatures the moisture naturally in the air settles on cold surfaces such as un-insulated walls, ceilings and windows as condensation.  Condensation and cold are the perfect conditions for growing mould which thrives in humidity greater than 70% on cold surfaces with condensation potential.

Mould, with its tiny spores, is at the root of many respiratory illnesses and asthma as well as some forms of gastroenteritis. Fungi growth affects about 40% of New Zealand homes and can cause adverse health effects such as respiratory illnesses, asthma and allergies.  Dust mites also thrive in humid environments, exacerbating asthma and allergies.

The Otago University Wellington School of Medicine Housing Insulation and Health study found that increasing the temperature in New Zealand homes by only 1°C to 12.7°C significantly reduced the number of hours that the indoor relative humidity was in excess of 75%. 

Reducing indoor moisture

As well as preventing condensation inside the home, A healthier home gets rid of moisture at its source: by stopping moisture coming into the home and by ventilating to get rid of moisture.   Moisture accumulates in a house from people bathing, showering, cooking, breathing, and watering plants. It also comes into a home from outside. Some appliances, such as unflued gas heaters, clothes dryers, dishwashers and washing machines, also produce excess moisture into the air.

The moisture builds up quickly and is worse in modern homes which are built to be almost airtight and have no ventilation. If the indoor temperature is cold, you can see the moisture when it collects on the windows as condensation. It is also absorbed into fabrics and building materials. This moisture build-up causes mould and mildew on walls and fabrics, which is not only unsightly, but can trigger allergies. For example, dust mites - the source of one of the most powerful biological allergens - thrive in damp conditions.

It takes more energy to heat moisture-laden air than dry air, so reducing moisture inside will also help keep your home warmer.

Ventilate for a dry and cool indoor environment

Drawing fresh air into your house helps prevent dampness.  As house construction methods have developed over the years, the airtightness of houses has increased. This has placed greater importance on ventilation methods to ensure that sufficient fresh air is provided to the occupants of the homes.

Poor ventilation allows moisture and airborne pollutants to build up inside your home. This can cause health problems, make your home uncomfortable to live in and damage its structure. Ventilation is also a means to controlling summer overheating.