Health burden of cold damp houses costs millions every year

I’ve often wondered in the past exactly what percentage of New Zealand’s health burden is due to our damp and cold homes. Well I obviously didn’t look in the right place. PHINZ chair Elrond Burrell last month linked to a short 2011 study that provides the exact numbers I’ve been looking for.

An article by Brad Prezant titled “Calculating the burden of disease attributable to indoor dampness in New Zealand” clearly states that it is reasonable to calculate that 25-33% of the disease burden of asthma et al is attributable to damp homes. Cold indoor temperatures are probably part of this impact but it’s hard to pull out. This makes sense to me from a building science perspective, as cold and mould tend to go together.

This link between dampness and disease has been widely shown. Prezant says there is a “remarkably consistent association between home dampness and respiratory symptoms and asthma has been observed in a large number of studies conducted across many geographical regions.”

“In aggregate, our results suggest that approximately one quarter to one-third of the respiratory health outcomes, in particular those health outcomes associated with asthma, can be explained by indoor dampness. The list of health outcomes for which a PAF was calculated includes exacerbation of pre-existing asthma, new asthma, and increase in symptoms such as cough, wheeze, bronchitis, allergic rhinitis, and eczema. “

In case that sounds bad let me clarify how bad. The NZ Asthma Foundation put hard numbers on the problem: 

• The cost of asthma to the nation is over $1 billion per year.
• Respiratory disease costs New Zealand more than $7 billion every year

(Research by Barnard & Zhang, 2018.)

At the low end of Prezant’s range, 25% of $1 billion per year is $250 million dollars every year. Based on two million households in New Zealand, that works out at $125 per year per household. Based on a typical dwelling lifespan of 100 years, that would justify spending approximately $12,500 per household just for health savings alone.

At the high end, the health savings could be as high as 33% of $7 billion or $115,500 per household in health savings over 100 years.

Damn, that seems like a LOT of money.