Seventy per cent of two-person households and 54 per cent of one-person households in Ireland are living in homes with five rooms or more, according to new figures compiled by the Central Statistics Office (CSO).
A report commissioned by Lisney estate agents, The Distribution of Ireland's Housing Stock - Square Pegs for Round Holes, also found that fewer than 1 per cent of large households (five persons or more) live in two rooms or less.
Census 2006 figures show that, although more than half of Irish households are small (ie they contain just one or two persons), almost three-quarters of the 1,769,613 homes in the State are relatively large (ie they have more than five main rooms).
As the census does not co-relate the number of persons in a household with the number of rooms they occupy, Lisney requested the CSO to cross-tabulate the data on household size with the data on number of rooms occupied.
The results show that 10.5 per cent of large households (five-plus persons) are living in four rooms or less. As this represents just 1.5 per cent of all households, "overcrowding does not appear to be a widespread phenomenon", Lisney Research said.
Conversely, the report found that 450,474 one- and two-person households (63 per cent of the total) live in properties with five rooms or more - a category that accounts for nearly three-quarters of all residential properties in the State.
According to John McCartney, head of Lisney Research, the figures "suggest that many small households have space which is surplus to their absolute accommodation needs" - a situation he conceded was probably a conscious choice for many people.
"However, there may also be smaller households which might wish to downsize.
"This group is likely to include 'empty nesters' whose children have moved out of the family home [ and who] may find that their larger dwellings have become unmanageable."
"Trading-down could release housing equity which may be appealing to older couples on fixed incomes.
"Other smaller households that might wish to downsize include the increasing number of families affected by divorce and separation," Dr McCartney said.
"It is reasonable to assume that some of these households would like to downsize, but are deterred from doing so by existing stamp duty rates.
"Stamp duty changes which reduce the costs of moving will facilitate these households in trading-down.
If stamp duty was "banded" so that higher rates would only apply to the portion of the property price above certain thresholds, "this would release bigger properties on to the market, thereby meeting the accommodation needs of larger households".
"For a couple trading down to the average Dublin property, the proposed banding measures would bring savings of around €16,000.
"This would. . . have the knock-on benefit of freeing up bigger properties for growing families that need the space."
Given that the CSO report does not indicate widespread overcrowding, Dr McCartney said the new data should also "feed into discussions on Dublin City Council's recent proposals to increase minimum apartment sizes to make them more suitable for family living".