Case Study: nZEC - Energy refurbishment of 29 dwellings in Knyaz Boris I Street, Sofia, Bulgaria

Short Description

The project was carried out because of the high price for heating and the uncomfortable indoor climate. The project was implemented on the initiative of the homeowners association. The building construction type is brickwork on concrete skeleton. The heating of the building is district heating hot water type. There is a heat exchanger located in the basement.

The investment project for building energy renovation comprehends a complete refurbishment of the building envelope – thermal insulation of the external walls, the roof, the ground slab and replacement of the window frames with PVC double glazing. The project also includes renovation of the common areas – staircases, building installations, etc. The decrease in the energy consumption for heating is achieved by: decrease of thermal transmittance (U value) coefficient of the external walls; decrease of thermal transmittance (U value) coefficient of the roof; decrease of thermal transmittance (U value) coefficient of the building ground slab; decrease of thermal transmittance (U value) coefficient and the infiltration of the windows and the doors. The achieved reduction in energy use is 49%. The achieved reduction in greenhouse gas emissions is 43 t/y.

Key Elements

Certification

Energy certificate. Private energy auditing.

Project Management

Monitoring service quality.

Work with Residents

Support and advice for homeowners during the project preparation phase and the approval of the investment needed for the planned energy renovation measures; support and advice for homeowners during the project implementation phase; advice for homeowners on the subsequent management and maintenance phase.

Funding

Renovation costs paid by the residents.

Solar Thermal

Thermal insulation system for the building envelope – external walls, roof, ground slab; replacement of the existing window frames with PVC double glazing window frames.

Heating and Hot Water

District heating with hot water.

Main Results

Increased comfort of the living environment with higher quality of indoor climate at the same pre-renovation annual energy expenditure. Increased value of the apartments. Protected building structure without thermal bridges.

Lessons learned

Need to raise the awareness of homeowners through trainings and information campaigns before taking any actions for energy renovation of multi-story apartment buildings in order to make informed decisions on the type of measures needed.

Additional Information

Ms Eleonora Gaydarova
CAC - The Bulgarian Union of Homeowners Associations
E-mail: cac@mail.orbitel.bg
Web: www.cac-bg.org