Families caught in the rental trap are being hit with higher heating bills because their homes are generally less energy-efficient.
The Economic and Social Research Institute (ESRI) says as many as one in three homes across the country are expensive to heat because they are older and have less insulation. Families in the rented sector are more likely to live in these properties.
The analysis also suggests that the elderly and people who are mortgage-free and own their homes tend to incur higher heating bills, but this is probably because they are living in older properties.
The report suggests that Government policy to improve the efficiency of the residential sector should be targeted at rented properties and those owned outright to make the maximum gains.
The analysis used data from the Central Statistics Office and Sustainable Energy Authority of Ireland to examine the efficiency of 1.6 million homes across the State.
Some 40pc of all energy consumed is used in residential buildings, and Ireland must reduce consumption by 20pc by 2020 to meet EU targets. Some 26pc of the target has been met, reducing bills by €470m.
Homes are rated using a Building Energy Rating (BER). The rating is a simple A to G scale. A-rated homes are the most energy-efficient and will tend to have the lowest bills, with G being the least efficient.
Any property must have a BER before being offered for sale or rent, and around 30pc of all homes have been assessed.
The analysis looked at the occupants of these homes and found that 40pc of all rental properties fell into the 'E', 'F' or 'G' BER bands, meaning they were least efficient.
Homes which cost €2,000 or more to rent per month were found to be least efficient. These are generally three-storey, redbricked period properties in Dublin.
It also found that some 57pc of people aged 75 or older lived in the least-efficient homes. Many of these residents would be "hesitant" to pay for upgrades, regardless of affordability, due to the inconvenience.
In families where no person was in employment, 44pc lived in poorly-rated homes. This fell to 30pc where there was one income. Many of the homes are located in the Midlands, where coal and peat are primarily used as fuel sources. These inefficient fuels reduce the energy rating of the building.
There was also a high incidence in Dublin and Cork, where the building stock would generally be older.
The report says that efficiency schemes should be targeted at low-income groups, unable to fund upgrades.