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Dr Stephen Bridgman: Winter wellness starts with a warm, dry home

Dr. Stephen Bridgman, Medical Officer Health, Public Health Physician, on how ventilation and insulation can improve the health of our homes and the health of our families. 

Rates of colds, flu, and, more recently, COVID-19, increase during the winter months because wintertime conditions create a favourable environment for viral spread. First, there’s less sunlight in winter meaning there are lower levels of ultra-violet light to harm viruses. Second, humidity is higher, allowing viruses to survive outside of our bodies for longer. Finally, we spend more time indoors during the winter which makes ventilation and physical distancing challenging.

As humidity and time spent indoors are major contributors to the spread of common winter illnesses, staying well this winter truly starts with a warm and dry home.

Though winter favours viruses, ideally our homes should not. Cold indoor temperatures lead to dampness, creating the kind of humid conditions viruses survive in for longer. Increasing heat, reducing dampness, and improving a home’s ventilation is an essential part of slowing viral spread in winter.  The World Health Organisation recommends indoor temperatures of 18°C, or 21°C if the household includes babies and/ or elderly people. Most houses in New Zealand average just 16°C.

Below 16°C the risk of respiratory illness increases. This is because in a cold indoor environment our day-to-day activities like cooking, showering, and even breathing, create condensation. Condensation gathers on cold surfaces, such as uninsulated walls and ceilings, and can lead to mould growth. Dampness is a health risk in itself, but mould can contribute to respiratory problems. Mould affects asthma sufferers and those with pre-existing respiratory conditions in particular.

Poor quality housing and structural issues in homes make maintaining warmth very challenging. Most New Zealand homes have at least some insulation, but many have defects like gaps in ceiling insulation, and in 2010 a study showed that 45% of houses did not have under-floor insulation. Sufficient insulation is the first place to start in making a warm home—insulation keeps the heat in and lowers heating costs.

Making a warm, dry home:

  • The HomeFit online check can help you assess where a home is lacking when it comes to being warm, dry, safe, and efficient, and provide local contacts for installers who can improve the condition of the home.
  • Homeowners who meet certain criteria are eligible for 80% off the insulation or heaters through the Warmer Kiwi Homes programme
  • Landlords have an obligation for their properties to meet Healthy Homes standards, which include fixed heating devices and insulation. If your rental property does not meet these standards, read about how to raise concerns with landlords here.

Keeping a warm, dry home:

If the insulation is sufficient, the next piece to tackle is a safe and efficient heater. Options include heat pumps (especially with thermostats), electric heaters, wood burners, and wood pellet burners.

Wood burners contribute to air pollution, especially in urban areas. Wood burners should be avoided if possible, but if they the only option in your home, the outdoor air pollution can be can lessened by burning dry, seasoned firewood. Nelson City Council and Tasman District Council are supporters of the Good Wood scheme: advice for better burning and a directory of suppliers who meet Good Wood criteria.

Following warm home tips, such as drawing curtains at night and opening them in the day or using draught stoppers, can help keep heat in. Increasing ventilation and reducing dampness is equally important: dry air is easier to heat.

Opening windows for just two to three minutes at a time at least once a day in winter greatly improves a home’s air quality and ventilation and is free to do. Airing the home reduces condensation. Using extractor fans in the kitchen when cooking and the bathroom when bathing or showering also reduces the condensation that leads to dampness.

If mould does occur it can be removed with a bleach solution (2 teaspoons of bleach to 1 litre of water), or use white vinegar (without any added water).

Visit our Healthy homes webpage to explore new features on making and keeping a home warm and dry.


  • Golden Bay residents can connect with a Heartland Services Coordinator for help navigating Tenancy Services, Kāinga Ora, healthier homes, and more.
  • Whānau can register their interest with Whānau Power. Whānau Power can navigate dependable powers suppliers and healthy whare solutions with you.
  • Work and Income may be able to help with an urgent power, gas, or water bill, or the costs of heating.
  • If you’re over 65, Age Concern can link you with Social Work support to help you access resources, services and information you may need this winter. Call them on (03) 544 7624.
  • If you need assistance affording bedding, curtains, heaters, or clothes, contact:
    • St Vincent de Paul: Call (03) 548 9372 (Nelson); (03) 547 7351 (Stoke); (03) 544 0893 (Richmond, Moteuka and Golden Bay); (03) 573 5475 (Picton), or (03) 577 8378 (Blenheim) and ask to speak to the Welfare Support worker.
    • The Salvation Army:
      • Nelson: Call (03) 548 4807 and ask to speak to the Social Work team or email [email protected]
      • Blenheim: Call (03) 578 0862 and ask to speak to the Social Work team or email [email protected]

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