The health service faces a bill of £33m a year if the worst health and safety hazards in Northern Ireland houses are not tackled, a new report has warned.
According to the Housing Executive's The Cost of Poor Housing in Northern Ireland, cold and damp properties are contributing toward a variety of illnesses.
The review of housing indicates that a serious safety hazard has been identified in a fifth of homes, with serious fall risks and excessive mould growth among the catalogue of problems arising.
Northern Ireland homes dating back to the First World War and earlier are most likely to be flawed, as they have very limited insulation and often, very steep staircases.
The report indicates that the total cost of addressing the most serious hazards could be around £469m.
The research also demonstrates that simple home safety improvements, such as handrails and hard-wired smoke and carbon monoxide detectors, are very cost-effective.
However, it is more difficult to demonstrate the cost-effectiveness of remedial works to deal with excess cold and damp problems across the whole housing stock, as such work can be much more costly. The extensive review of housing stock also recommends more is done to address the impact of poor quality housing on mental health, educational attainment, quality of life and social participation.
The new research examines the 2009 Northern Ireland House Condition Survey.
It suggests some 144,000 – one in five – of Northern Ireland's homes had at least one serious hazard.
Despite this, the region has the most modern housing stock in the UK and proportionately less poor housing.
Rural homes are more commonly hazardous than urban ones, as on average they are older or likely to have been left vacant.
Privately-owned houses are twice as likely to have serious hazards as those in the social sector.
John McPeake, chief executive of the Housing Executive, said: "At a time of severe constraints on public expenditure, this report is a very welcome addition to the underlying evidence base for well-targeted public investment in housing."
He said it "would not only bring significant improvements in the physical and mental health and wellbeing of households, but would also increase the value of the housing stock and could facilitate very considerable savings in the health budget in Northern Ireland."
* High fuels costs in Northern Ireland contribute towards 44% of households being classed as in fuel poverty.
* The average number of excess winter deaths caused by cold in Northern Ireland from 2001 to 2009 was around 500 per year. This rose to just over 1,000 in 2008-9 due to the particularly harsh winter.