Is Your Home Making You Sick? An Indoor-Air and Health Self-Check

It might be. A home does not infect you, but a cold, damp, mouldy home creates conditions that are linked to respiratory illness, allergies, worse asthma and poorer general health (BRANZ HEEP2). If your family seems to get more coughs and colds over winter, or someone’s asthma is worse at home, the building could be part of the story.

This is not rare, and it is not your fault. New Zealand has a well documented problem with cold, damp housing, and most of it comes down to how homes are built. The good news is that because the cause is the building, it can be measured, understood and designed out. Start with the simple self-check below.

Walk through your home and look for these signs. Each one points to damp, cold or poor ventilation, and each has a clear fix in a healthy home. The more you recognise, the more the building is working against you.

If you ticked two or three, your home is likely cold or damp enough to affect comfort and health. If you ticked most of them, the building is the problem, and patching one symptom at a time rarely fixes it.

Cold, damp and mould are linked to real health effects, not just discomfort. Damp air and mould feed respiratory problems and trigger asthma and allergies, while a cold home adds cold stress that is hardest on babies, children and older people (BRANZ HEEP2).

The New Zealand evidence is sobering. BRANZ HEEP2 research, covering more than 750 households, found about half had visible mould, about one in five people reported seeing their breath indoors and shivering in winter, and about a third said their home was damp at least some of the time (Sustainable Engineering). About 28,000 homes are always damp and always have visible mould (Stuff). The hardest part is how normal this has become: most people still consider their home healthy despite the cold and the mould. It does not have to be that way.

Because most homes are built to the Building Code minimum, which the SuperHome Movement notes sits well behind comparable countries. A home built to the minimum often has modest insulation, a leaky envelope, low-spec glazing and no controlled ventilation, which is exactly the recipe for cold and damp.

It is also why being a new build does not guarantee a healthy home. A new house built only to the Code can still get condensation and mould from day one. Modern homes are often tighter than old ones without adding ventilation to match, so moisture from everyday living builds up with nowhere to go. The fix is not to leak more, it is to insulate, seal and ventilate on purpose. Our guide to why NZ homes are cold and damp goes deeper on the causes.

It depends how far gone the building is. Some homes can be improved with added insulation, better glazing and mechanical ventilation, and that is worth doing where the bones are sound. The honest catch is that retrofits are often partial: it is hard and costly to reach a genuinely warm, dry result in a home that was never designed for it.

Where a home is fundamentally cold, damp or poorly laid out, a new build or a knockdown rebuild is often the cleaner answer, because you design the problem out from the start rather than chasing it. If you are weighing the options for a long-term, healthy home, that decision is worth costing properly before you commit.

A healthy home is built, not bolted on. Four building-science measures work together to remove the conditions that make people unwell: continuous insulation, an airtight envelope, high-performance glazing, and mechanical ventilation with heat recovery. These are the core of the Passive House standard.

Insulation and airtightness keep the home warm and stop the draughts. High-performance glazing keeps window surfaces warm so condensation cannot form (Koffman). Heat recovery ventilation continuously removes moist, stale air and supplies fresh, filtered air, which keeps humidity down and filters out pollen and outdoor particulates, a real benefit for anyone with allergies or asthma. Thermal-bridge-free detailing removes the cold junctions where mould starts. The result is a home that is warm, dry, quiet and healthy without a fight. For how these work together, see the five principles of a Passive House, and for whether the investment stacks up, whether a Passive House is worth it. This is the heart of Ecotectural’s design and build approach.

If your home has condensation, mould, a musty smell, cold rooms or stuffy air, it may well be affecting your health, and you are not imagining it. Cold, damp, mouldy homes are linked to respiratory illness and poorer health, and they are common in New Zealand (BRANZ HEEP2, Sustainable Engineering). The cause is the building, which means it can be fixed.

A warm, dry, well-ventilated home, built with continuous insulation, airtightness, high-performance glazing and mechanical ventilation with heat recovery, removes the conditions that make people unwell, and keeps doing so for the life of the home. If you are planning a build in Nelson Tasman and want a home that protects your family’s health rather than undermining it, the best first step is to arrange a consultation before the design is locked in.