Firstly, no this is not an April Fools' joke. It is simply ANOTHER regulation applicable to privately rented properties. Unfortunately it is about as enthralling as other recent regulations, but important all the same. So, in a nut-shell...
As of the 1st April 2016 tenants in privately rented properties will have the right to carry out energy efficiency improvements to their property, but only with the consent of the landlord. Before you spit your coffee over your keyboard it's worth mentioning at this point that the landlord does not have to pay.
The request for consent to proposed improvements must be in writing and outline the measures as to the funding of said improvements, whether privately by the tenant or through an energy efficiency scheme such as the Green Deal.
These new regulations cover any property defined as a privately rented property whether the property has an EPC at the time of the request, or not. It is also worth mentioning that the landlord may not unreasonable deny consent to the tenant and must reply within a month. Also, there is a right to appeal if the tenant is not content with the landlord's response.
There are exceptions to the rule. For example, a landlord of a property that does not fall under the scope of EPC regulations would not be required to provide consent to energy efficiency improvements.
So, there we go. A very brief outline of these new regulations. For a more in-depth look you may want to click this link.