Bulgaria has insulated 454 apartment blocks with money from its EU recovery plan so far, the regional development ministry said. Together they have more than 2.2m sq m of floor space.

The ministry has also signed contracts for another 630 buildings, with nearly 1.3m sq m of built floor space. The Bulgarian Development Bank now manages these projects after they were transferred to it. Work continues and must finish by 2029.

In Plovdiv, Silvia Petrova, head of the ministry's housing policy directorate, said the ministry will report by the end of the year on the other buildings where repairs are already finished.

One example is a block in Svishtov, where just over €1m was spent. The walls and roof have new insulation, the windows have been replaced, and the shared areas have fire doors and energy-saving lights. The block now uses nearly 68% less energy a year.

Petrova said the aim is to remove money barriers for households and to support people who struggle to pay their energy bills. The ministry is looking at ways to avoid making residents pay their share of the costs.

"The ministry is focusing on steady preparation of the next projects while the current ones are under way," she said.

The upcoming National Building Renovation Plan should set long-term goals and priorities. It should also line up the sources of support: the recovery plan, the Just Transition Fund and the measures now being prepared under the Social Climate Plan.

Petrova said energy repairs should go together with an assessment of the building's condition. This covers structural and fire safety, ventilation and protection from overheating in summer.

Petrova added that how long the investment lasts depends on a good survey and design, on checks during construction, and on upkeep afterwards.