JUST one-in-20 new homes has achieved the top energy rating since the compulsory scheme was rolled out four years ago.
Just 1,980 of the almost 30,000 new homes rated so far for energy efficiency got an A grade.
Building Energy Ratings (BER) certs have been mandatory for property sales since 2009.
A BER is similar to the energy label for a household electrical appliance like a fridge – and is an indication of the energy performance of a home.
From next week the rating must also be included in all newspaper or web ads, similar to those on fridges for example.
The label has a scale that ranges from A to G, with A-rated homes (Green) being the most energy efficient, and G (Red) the least.
But very few got an A grade – within those that did, just seven received an A1 grade, 59 got A2 and 1,320 an A3.
The majority received B ratings, equating to the prevailing building regulations.
And most of the 320,000 older homes that had BER certs carried out prior to being sold or let were in the mid range C category.
The Sustainable Energy Authority of Ireland (SEAI) said few homes would have an A rating as it is a very high energy performing standard.
It would mean a near zero-energy home – a building that creates enough green energy on site to power itself.
It would require some form of electricity generation such as wind turbines or solar.
Most landlords and homeowners are required by law to have a BER certificate for their property so that potential renters or buyers know how energy efficient it is. It helps assess the running cost of the home.
The BER cert covers energy use for space heating, water heating, ventilation and lighting calculated on the basis of standard occupancy.
A BER certificate is accompanied by an advisory report which will identify how you might improve the energy performance of your home.
SEAI chief executive Brian Motherway said: "The new requirement to display BERs in property adverts from January 9 is good news for consumers as more and more people will become aware of the energy performance of a property before they even consider buying or renting it.
"The bottom line is the better the BER, the lower the running costs for the home."
Ed Carey, chairman of the residential property group of the Society of Chartered Surveyors (SCSI), said the energy rating of a property must be published on all marketing materials relating to the property.
"My advice for anyone considering selling or letting their property is to have their property energy rated as the first step before contacting an agent, as the agent will not be in a position to market the property until they have the BER certificate."
However, a consumer watchdog recently called for a review of the BER system after a price survey revealed huge differences in fees quoted by providers – with some charging 100pc more than others.
A survey by the Irish Independent found a huge difference in the fees charged by assessors, with prices ranging from €150 to as much as €369.
Dermott Jewell, chief executive of the Consumers' Association of Ireland, said that even accounting for different business costs, it was hard to justify the enormous gap in prices.
The SEAI recommends property owners shop around for the best price possible.
There are 1,466 approved BER assessors registered with the authority.