The deal applies to residential properties purchased with an Energy Efficiency Rating of A or B including new builds and is available at 60 per cent, 75 per cent and 85 per cent loan to value (LTV).
Two-year and five-year versions are available with all deals having a £995 product fee and cash back of £250.
For example, the two-year 60 per cent LTV product is at 1.33 per cent, compared to 1.46 per cent for the standard equivalent.
The five-year fix at 85 per cent LTV is at 2.99 per cent, compared to 3.29 per cent for that standard equivalent.
NatWest said its green mortgage supports the bank’s pledge to help customers become more energy efficient and continues its ambition for half its mortgage book to be at or above EPC C or equivalent rating of C by 2030.
Miguel Sard, managing director of home buying and ownership at NatWest Group, said: “We want to help home buyers to make greener choices, particularly as properties make up 15 per cent of the UK total climate emissions and one of the core parts of our purpose as a bank is to help address the climate challenge.
“Our customers are increasingly interested in purchasing energy efficient homes and by offering those customers a lower mortgage rate, we want to have a positive impact on the environment.”
NatWest also made a series of other product changes alongside bringing in the green mortgages, which included raising rates across its range and withdrawing its broker exclusive two-year and five-year fixes with £995 fee.