Cavan County Council is spending €14,000 more on social housing units from private developers when compared to building directly.
Typically, one-third of social housing units are direct builds, while two-thirds are turnkey acquisitions from private developers.
2019 figures which have been obtained by Sinn Féin from the Department of Housing reveals that the average social housing unit when built directly by Cavan County Council costs around €169,500.
However, the average turnkey property costs the council €183,800.
While it costs less for councils to build directly in many areas, it costs around €5,000 more in Monaghan, at €182,400.
Councils usually procure around two-thirds of their social housing needs from private developers.
In some local councils, the average turnkey acquisition is almost double the cost of a direct build from the council.
In Dublin City, the council can build a social housing unit for around €181,000, while the average privately developed turnkey unit costs over €382,000.