Initially, improvements only had to be made to domestic properties if they could be achieved “at no cost” to the landlord.  This policy depended upon various forms of funding being available to make any necessary improvements.

Following the effective collapse of Green Deal funding and the withdrawal of many grants, the Government launched a consultation in December 2017 to review this policy.  This occurred just before the Energy Efficiency (Private Rented Sector) (England and Wales) Regulations 2015 began to take effect in April 2018 therefore little actual evidence was available about their real impact.  The consultation ran until March 2018 with summary responses being published in July 2018 before the Government responded with new policy in November 2018.  The new policy effectively requires landlords to spend up to £3500 inclusive of VAT (the cost cap) per property after 1 October 2017 in order to bring it up to the Minimum Energy Efficiency Standard (MEES).

A full response is available online:
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/753710/Final_PRS_Minimum_Standards_Consultation_Government_Response.pdf

It should be noted that the Minimum Energy Efficiency Standard (MEES) for homes is now planned to increase to Energy Performance Certificate Band C over the next few years.  It is likely that additional investment above the current cap will be required as these standards are raised.

You can find out more about funding domestic improvements in our "How do I fund MEES improvements to a domestic property?" FAQ.