Haven, a subsidiary of AIB, is introducing a green mortgage with a rate of 2.15% - one of the lowest in the market.
The four year fixed rate will be available from 8 July, to new and existing customers whose properties have a Building Energy Rating (BER) of between A1 and B3.
Haven said existing customers can qualify by having four years or more remaining on their mortgage.
Customers who switch their mortgage to Haven and avail of the new green rate will receive €2,000 towards legal costs.
Kieran Tansey, Haven Managing Director said the new rate will offer customers "substantial savings" on their monthly mortgage repayments, compared with variable rates.
"Haven’s green four year fixed rate mortgage will also provide customers with greater repayment certainty and the opportunity to fight climate change by reducing their personal carbon footprint," he said.
With a 25 year mortgage of €305,000, Haven said customers could save €155.11 per month or €1861.32 a year with the new rate, when compared to a variable rate mortgage for the same amount and term.
The new rate is only available to customers who apply through a Haven appointed mortgage intermediary.
Joey Sheahan, Head of Credit with MyMortgages.ie welcomed the news.
"This is a fantastic switching opportunity for those that are in a relatively new house with an above B3 rating or those that have already retrofitted their homes to that level," he said.
"A homeowner with an existing mortgage of 300,000 on a house worth 350,000 or more could save €267 per month or €3,204 annually or €12,816 over 4 years if they switch from a more typical variable rate of 3.7% and lock in to this four year fixed rate of 2.15%," he said.
