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A pilot project for indoor lighting improves visual comfort in classrooms and saves energy


The building housing Stephan Karadja primary school, situated in the city of Varna, Bulgaria, was in poor condition before the implementation of the project described in this shining example. The wooden window frames were worn out and although there was double-glazing, this did not help a lot because of the considerable number of broken windows. The indoor lighting was below suggested standards. There were a lot of damaged fixtures and either missing or inefficient old luminaries.

In 2005 the school was chosen for the implementation of a pilot project for indoor lighting rehabilitation by the Educational Department of the City of Varna, which is responsible for all schools and kindergartens of the municipality.

Building details

Type of building
Primary school

Year built/ Floor area/ Operating hours
The primary school Stephan Karadja was built in 1960. The total floor area is 3,700m2 and the school is open 60 hours a week, from Monday to Friday, from 7:00 a.m. to 7:00 p.m.

Heating and cooling installed
The building is heated by a local naphtha-fuel boiler house.

Energy label/ CO2 emissions
The Display® posters for 2005 and 2006, before and after reconstruction of the lighting system of the school, show that both energy consumption and CO2 emissions have improved by one class:

_ 2005

- Energy: C
- CO2: C
- Water: E

_ 2006

- Energy: B
- CO2: B
- Water: E

_ The energy consumption for 2005 was 153kWh/m2/year, rated as Class C. After the reconstruction the consumption was reduced to 105kWh/m2/year and the class moved up to B. The CO2 emissions changed from class C to class B – from 39kg/m2/year to 27kg/m2/year. The water consumption in 2005 was rated as class D with 600 lm2/year. Although the consumption in the next year was lower – 485 lm2/year it was not enough to change the class.



The aim of this project was to show that improving indoor lighting will not just improve indoor comfort for pupils and teachers but will lead to the reduction of energy costs and CO2 emissions.

Key points
The improvement of indoor lighting has a big potential for energy saving in schools. For this reason, in 2005 the Varna Municipal Council approved the proposal of the Educational Department for a pilot project to upgrade the lighting system in Stephan Karadja school.

_ The whole lighting system of the school was renovated and all lamps were replaced with energy efficient compact fluorescent lights. The work was undertaken by a Bulgarian company, who were selected after a tender and bidding process.

_ At the same time, wooden window frames on the northern façade were replaced with PVC frames. The remainder of the window frames were not replaced. Due to insufficient financial resources, many municipalities only replace frames on the northern façade to limit the impact of the northern façade’s exposure and improve to a certain extent the building’s performance.

_ After the lighting project was implemented, special classes on environmental issues were organised. During these classes, pupils were acquainted with the importance of the quality of indoor lighting for their health; how these energy efficient lamps can save energy and CO2 emissions and how the money saved from the lower energy bills can be used for other activities in the school. The teachers explained to the pupils how they can ”help” the new lighting to be even more efficient by changing their habits and opening the curtains and switching off the lights when they don’t need them. The pupils were also given examples of how they can reduce their family’s energy bills through simple energy saving measures.

Reason for inclusion as Shining Example
What makes this project involving the improvement of a school’s lighting system, a good example to follow is the fact that even such a simple measure can have a significant impact on energy consumption - enough to improve the Display® ratings for energy consumption and CO2 emissions by one class.

Costs &


Costs &


This pilot project cost €34,300 (BGN 67,000) and was fully funded by the Varna Municipality. The payback period for the project is 3.5 years.

This pilot project has improved the indoor comfort and working environment for pupils and teachers, as well as reducing energy consumption by 48kWh/m2/year (a total of 135 MWh/year) and CO2 emission by 12kg/m2/year. The project has not resulted in very big monetary savings - around €250-€500/year (BGN 500-1000). However, the impact on the behaviour and habits of the pupils and their families, teachers and the school’s administration is of great importance. The improved working conditions is also very important.

Partners & Roles

Partnership details
This project was financed by the municipality. Varna Municipality is a member of the Bulgarian municipal energy efficiency network EcoEnergy, which supported the participation of its members in the Display® campaign and helped to organise awareness raising activities in the school after the renovation of the lighting system.


In the Varna Municipality, the monitoring and evaluation of energy efficiency projects is undertaken by the school’s administration together with the Education Department of the municipality. This department develops annual plans for the refurbishment of schools and kindergartens, analyses the results of the refurbishments and makes proposals to the City Council for the allocation of funds for these projects.

_ The school’s administration intends to introduce energy management in the school because it believes that this can help to achieve long lasting results. It also plans to apply to the municipal administration for financing of other measures, such as heat insulation for the whole building and full replacement of the wooden window frames.

Lessons Learned
This type of project is applicable to all schools and kindergartens in the Municipality of Varna. However, for the achievement of better results, several energy saving measures can be combined into a package at the project development stage.

To know more

Organisation name
Varna Municipality

Daniela Kuzmanova

+359 52 659 126



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