Everything is explained in great detail and all the dates applicable. So as Adrian says , the Act does not kick in for CURRENT tenancies for 12 months and is only an update on the old act.
As this is not really a new piece of legislation, it is an amendment to sections 8-10 of the 1985 Landlord and Tenant Act, with the addition of new sections 9A, B and C. What it does do however is give a route for tenants to seek redress from landlords without having to wait for the Council or EHA to act. I am of the opinion it will only be a matter of time before this Act will be quantified by case law, as yet the degree of un-inhabitability is not quantified and the landlord has to be allowed reasonable time to rectify.
It still relies on the 29 Hazards listed in Schedule 1 of The Housing Health and Safety Rating System (England) Regulations 2005 to define why a property may not be fit for human habitation, but the new section 9A inserts a covenant between landlord and tenant that the property is and will remain habitable.
Three other things to keep in mind. Most of this Act only refers to England. What defines fitness for human habitation will only be determined by case law. Although the new act comes in to force on 20th March 2019, no one on a current tenancy will be able to use it for another year and it does not protect anyone with a tenancy longer than 7 years.
Adrian can be contacted on 0161 633 9860 or firstname.lastname@example.org