The Social Housing Decarbonisation Fund (SHDF) will upgrade a significant amount of the social housing stock currently below Energy Performance Certificate (EPC) band C up to that standard. The latest wave, wave 2.2 has now closed, but more funding has been allocated for this fund, with applications opening 2024/25. 

https://www.gov.uk/government/publications/social-housing-decarbonisation-fund-wave-22