As well as the extra monetary cost that comes with heating homes in winter, there's a significant health cost in Hawke's Bay, says Hawke's Bay DHB acting chief medical officer and paediatrician Russell Wills.
"Household overcrowding and cold damp houses are a big problem in Hawke's Bay where the quality of the rental stock is particularly poor.
"Our community teams are frequently visiting whanau in houses that are colder inside than outside during winter and they frequently see dampness and mould on the walls and curtains."
In addition, in order to save money on heating it was common that whanau was only able to afford to heat one room so everyone slept together in the lounge, which led to viruses spreading very quickly between family members.
"A common situation is for an older sibling to bring home a cold from school, and then Nanny with her chronic illness gets sick and the baby gets sick.
"The oldest and the youngest are often admitted to hospital."
Dr Wills said 3000 children were admitted to Hawke's Bay Hospital each year of whom three-quarters were Maori and Pacific, three-quarters of whom were aged under 5 years old.
"It's the infants under 1 who are the most affected by respiratory illnesses."
In recognition of the issue, he said the Hawke's Bay DHB was an early adopter of the Healthy Housing programme, where when people were admitted to hospital they were asked about the quality of their housing.
If there were issues, public health nurses visited their home to assess them, and if it was a rental talk to landlords to encourage them to insulate and heat the house.
"They also educate whanau on how to keep their houses healthy in winter such as ventilating during the day to let the damp out, and simple things like stopping draughts.
"We have a relationship with the curtain bank to fit insulated curtains or arrange a handyman to fit curtain rails."
They also ensured families had a GP, that the children were immunised.
"There's very good evidence from New Zealand that insulating, heating and draught stopping make a huge difference to reducing admissions to hospitals as well as saving costs."
In terms of insulation, he encouraged landlords to check out what government subsidies were available to insulate their rental properties, which not only helped keep tenants warm and dry but also helped retain the value of the property.