It said up to one million private tenants will benefit from the changes, meaning homes will cost less to heat.
The new requirement has been introduced alongside measures that will prevent the small minority of rogue landlords evicting tenants because they have asked for essential repairs to be made.
According to estimates, the average difference in a heating bill from the least energy efficient properties to those with a Band E energy rating is £880. Individuals living in the least energy efficient privately-rented homes spend around £1,000 more to keep warm compared to the average home.
Financial support is available through the Green Deal and Energy Company Obligation, meaning landlords will not necessarily have to foot the bill for implementing the changes. The government said landlords will only have to make improvements that are cost effective.
The government has set April 2018 as the deadline for the changes, but from April 2016 tenants will have the right to request consent for improvements to make their homes more comfortable, and easier and cheaper to keep warm, which the landlord cannot unreasonably refuse.
The government said the changes would particularly help tenants on low income as well as vulnerable households.
Secretary of State for Energy and Climate Change Edward Davey said: “These new laws will plug the gaps in draughty homes – helping households to keep warm and drive down bills.
“Many of the poorest tenants will benefit and, with government support, landlords can improve their properties at no upfront cost.”
