The ban is related to the Diagnostic de Performance Énergétique (DPE), and affects buildings classified F or G.
It is the second blow to owners of such buildings, which represent 23% of the French rental market, according to figures from the government’s Commissariat Général de Développement Durable.
To be classified as a G in the DPE gradings, a building must use more than 450kWh/m2 per year, while an F grade must use more than 331kWh/ m2 per year.
Some experts said the measure was mainly symbolic, because rents in large cities are already subject to strict restrictions and cannot be raised when landlords change tenants, beyond limits set out every quarter.
They claimed the only buildings affected, with F or G energy ratings, were those with hardly any insulation. Another decree published by the government in mid-January banned all G-graded buildings from being rented out from 2023.
Existing tenants will be allowed to remain but if they leave, the landlord will not be able to rent it out before improving the DPE rating.
Housing minister Emmanuelle Wargon said renters whose buildings were brought up to scratch would save up to €1,000 a year in heating bills.
She promised DPE ratings would be included in estate agent adverts for rental properties, and possibly also in the adverts put by landlords on sites such as Le Bon Coin.
Landlords will be given an opportunity to challenge DPE ratings from July this year as part of a general revision of how the scheme works.
The inspectors who carry out DPE ratings are grouped into a trade federation – Fédération Interprofessionnelle du Diagnostic Immobilier – set up in 2004 after the first energy ratings were established for house sales.
Inspectors’ spokesman Stéphane Prouzeau, MD of a network of 156 cabinets, told The Connexion the wide range of building styles, materials, heating systems and water systems, and the age of buildings across France made it very difficult to generalise on the work needed to move from an F or G rating to an E or above rating.
“To move from a G rating to an A rating will most likely mean demolishing the building and starting from scratch with the best materials and skills available now,” he said.
“Usually, though, to move from an F to an E or D rating involves putting in insulation, first in the roof space and then on the inside of exterior walls.
“This is not very expensive – putting up rails and then fixing plasterboard with glass fibre wool is in the range of a couple of hundred euros, but what is expensive is smoothing it and painting it afterwards,” he said.
“Changing the heating system is important too – where people have old boilers, 40 years old, and replace them with new ones, they typically save 40% in their energy consumption, which is a lot. Similarly, some new hot water systems use much less energy than old ones.”
“Changing windows from single glazed to double glazing was usually fifth or sixth on the list, although it was one change which people appreciated the most.
“People feel the cold from single glazed windows in winter, even if it is a small part of the total picture,” he said. “That is why having double glazed windows seems to make more of a difference than it actually does.”
The rent control and other measures, although restrictive, were necessary if France is to meet goals of using less energy and cutting CO2 emissions, said Mr Prouzeau.
“Cars have gone from using an average of 11 litres of fuel per 100km 40 years ago to five litres per 100km now, and industry has greatly improved its energy use since the 1970s,” he said.
“Housing is one of the last major consumers of energy to be tackled and, over time, we will see significant improvements.”
The government is offering significant help for insulating homes used as a main residence, grouped under the MaPrimeRénov’ website.
For people buying property to rent, the main help in improving DPE ratings is a tax credit called Denormandie available in 222 towns in France.
Interest-free loans and VAT reduced to 5.5% also apply to rental energy renovation projects.
Some communes also cut taxe foncière for a period of time on properties which have had energy improvement work done.