Some 9 per cent of households say they have a major problem with heating and 7 per cent a major problem with dampness and mould.
That would represent around 140,000 and 110,000 children respectively, three-quarters of them in either private rental or social housing accommodation.
These statistics would come as no surprise to the medical professionals, community groups and others submitting to the select committee which considered Andrew Little's bill.
They do indicate that only a minority of landlords are letting out cold and damp properties - and that, shamefully, the state has to be ranked among the slum landlords. But the numbers are surely high enough to warrant regulatory intervention.
Another Statistics NZ source, the General Social Survey which ran over the 12 months to April this year, found similar results: 11 per cent of those in dwellings not owner-occupied said they had a major problem with dampness or mould.
It also found a significant difference between owner-occupiers and renters in self-assessed general health status, with 13 per cent of the former group rating their health fair or poor, but 17 per cent of renters. Unless you consider tenants as a population more prone to hypochondria, there is some information content in those numbers.
The Children's Commissioner told the select committee, citing New Zealand Child and Youth Epidemiology Service estimates, that over 40,000 children are hospitalised every year for conditions with a "social gradient" - that is, where socio-economic status affects health outcomes.
The Government's response to the Healthy Homes Guarantee Bill is that it is redundant. Its introduction predates the passage last year of legislation requiring all rental properties to be insulated by July 2019, three years earlier than Little's bill would require.
Nick Smith, the Minister for Building and Construction, said five of the six areas where Little's bill would require standards be drawn up are already covered by existing building regulations while the sixth, relating to minimum temperatures, would be unenforceable.
Some 300,000 homes had been insulated under the Warm Up New Zealand subsidy scheme (which is to be terminated by the middle of next year), he said. And the Government reckons another 180,000 will be insulated when the stick of the amended regulations replaces that carrot.
The issue was not the law but its enforcement, Smith declared. "That is why this Government proudly introduced the compliance and investigation unit. Last year we provided it with a budget. There are over 400 cases of prosecutions before the Tenancy Tribunal as a consequence of that law change that our Government made." Better late than never.
Smith also cited a report by the Building Research Association of New Zealand (Branz) that over the past five years the number of rental properties that had been improved rose by a "marked" 10 per cent. "This Government is not saying it is good enough ... but it is headed in the right direction."
The problem with this line of defence is that it comes from a Government which has been in power for nine years now.
It has to own those dismal statistics, which indicate that either the existing regulations are inadequate, as many contend, or they have not been enforced, as the Minister concedes.
To the extent that enforcement requires a tenant taking a landlord to the Tenancy Tribunal in times of acute housing shortage, that remedy is likely to be more theoretical than real.
National MP Matt Doocey raised the risk of unintended consequences from Andrew Little's bill. The cost of complying with the measures it would impose could be passed on in higher rents or remove some rental properties from the market altogether, he argued.
The "it will only push up rents" argument gets a lot of use, but it implies that the landlords in question - and remember, we are talking about a minority of landlords - are not already charging all that the market will bear. And that amount is set to increase when the accommodation supplement is raised, irrespective of whether there is a change of Government.
If investors are able to pay hundreds of thousands of dollars to buy a rental property, they can surely afford to spend a few thousand more, if needed, on insulation and a heat pump.
The last word on this should go to Labour MP Jenny Salesa, who told the House about the death of a 2-year-old girl in her Manukau East electorate. The coroner found that one of the main reasons she died was the poor condition of the house she lived in.
"The mother of this child went to the landlord many, many times, asking and begging the landlord to maintain the house that they lived in. This was a house that was cold, freezing, and mouldy, and it was not healthy. It was not just this child, who was a toddler, who was sick many times and who was in hospital for various conditions. Her older brother, who was six years old, had previously been diagnosed with rheumatic fever."
In this case the landlord was the Government, Housing New Zealand, Salesa said. "It should have actually done something to ensure that this family lived in a healthy condition. But it was not, until this child had passed away."
