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New efficient heating system improves a school’s indoor climate


The building of the St Cyril and Methodius general school in the town of Krivodol is a solid-frame brick structure consisting of two parts.

Prior to the implementation of the energy efficiency measures, the window frames were wooden. The building was heated by a local naphtha-fueled boiler house. The low efficiency of the heating system and the high operating costs led to a constant increase in energy consumption and energy bills, despite the fact that classrooms were under-heated. For these reasons, in 2004 the Krivodol Municipal Council decided to take implement measures to improve the building’s performance.
An energy audit was undertaken, which confirmed the inefficiency of the school’s heating system. The audit also confirmed that this inefficiency was the reason for the high operating costs and substandard temperatures in the classrooms. The main measures proposed by the audit report were:

- Installation of automatic controls for the heating system.
- Replacement of the old wooden window frames with energy saving PVC frames.
- Thermal insulation of the building.

St Cyril and Methodius general school

Building details

Type of building
General school

Year built/ Floor area/ Operating hours
The main part of the school building was erected in 1936 and the second part in 1956. The total floor area is 834 m2. The school is open 60 hours a week from Monday to Friday, from 7:30 a.m. to 7:30 p.m.

Energy label/ CO2 emissions
The implemented measures reduced energy consumption and the associated CO2 emissions and improved the indoor thermal comfort. The impact can be seen from the Display® ratings. At the end of the first reporting period in 2005, the building’s energy consumption reached Class B with 87kWh/m2/year. The CO2 emissions rating also reached B Class with 22 kg/m2/year. The water consumption was ranked Class A or 86 L/m2/year, which was the most outstanding achievement of the project. (Note: a Display poster was not produced for the year prior to implementation of the project, because the necessary data was not available).


2005 Display® poster, after implementation of the project



The aim of the project was to improve the indoor thermal comfort for pupils and teachers of St. Cyril and Methodius general school and reduce energy consumption by implementing energy efficiency measures. The project also aimed to reduce water consumption.

Key points
The first step was to undertake an energy audit of the school to identify the most appropriate energy efficiency measures. The audit identified several measures, which could lead to reduced energy consumption, and at the same time improve the indoor temperature providing a more comfortable working and learning environment.


_ The recommendations from the audit resulted in the following changes being made:

- An automatic control for the heating system was installed. This allows the indoor temperature to be kept at an optimal level during the school’s operating hours. Energy is also saved because the control is programmed to switch off the heating system when the school is closed.
- The worn-out, wooden window frames were replaced with new, energy saving PVC window frames, which improved the weather-proofing of the building.
- The building envelope and the roof were insulated.


Reason for inclusion as Shining Example
The school also had high water consumption, because the water piping in the building was worn out and had a lot of leaks. Therefore, all of the pipes were replaced, which fixed the leaks and led to the school achieving a class A Display® rating for water consumption.

_ In some smaller towns and villages in Bulgaria there are still some schools that operate in conditions that do not comply with heating and hygiene regulations. The success of this project can provide the impetus for other small municipalities to implement relatively simple measures that can improve indoor temperature for building users as well as considerably reducing energy consumption and energy bills.

Costs &


Costs &


The total cost of this project was €55,200 with a payback period of 4.6 years.

The energy saving measures implemented as part of this project resulted in a 32% reduction in energy consumption in the year following implementation. This represents a saving of 87 kWh/year, or €4,740/year.
Reduced energy consumption led to a reduction of CO2 emissions by 22 kg/m2/year.

_ The implementation of the energy efficiency measures in the building changed the attitude of pupils, teachers and administrative staff, as well as parents. Even the “new look” of the renovated school building and the improved indoor conditions were enough to convince the inhabitants of the town of Krivodol that their municipality is taking care of the environment by implementing measures to reduce energy consumption. The energy saving project and the energy labelling of the building using the Display® poster raised people’s interest and became a major topic of discussion in the school and the students’ homes.

Partners details

Partners & Roles
This project was funded from the Municipality’s own budget.

_ The opportunity to raise public awareness in regards to energy issues arose when the Municipality of Krivodol became partner in the Display® campaign in May 2006. At that time, 30 Bulgarian municipalities who were members of the Bulgarian Energy Efficiency network EcoEnergy, joined the campaign.
So far, Krivodol Municipality has produced posters for three municipal sites that have been rehabilitated in the last year. The Display® posters and the interest that they raised encouraged the municipality to plan a broad energy saving awareness raising campaign in its energy program for 2008.


For most Bulgarian municipalities, the monitoring and evaluation of energy efficiency projects is undertaken by the accounting department of the municipality and the school’s administration. There are no special structures or specially appointed people to do this very important work. For the past cople of years, the Bulgarian Energy Efficiency Network EcoEnergy has been trying to convince the municipal administrations of the important role that an energy manager can play in reducing energy consumption and protecting the environment.

_ There is no doubt that this energy efficiency project, the first for Krivodol, was a success, especially for such a small municipality. The results proved that energy saving measures can reduce energy consumption, save money and improve the comfort of a school and bring it up to required heating standards with relatively simple measures. The success of the project encouraged the municipality to undertake two more projects to rehabilitate municipal sites.

Lessons Learned
This project is widely applicable both to other schools and other building types, because it involves simple measures such as heating controls and insulation that can have benefits in terms of energy conservation, reduction of CO2 emissions and improvement of thermal comfort.

_ The municipality realised that if they want to expand their activities in improving the performance of their buildings they should look to diversify their funding sources and undertake schemes that will enable the implementation of more projects in a shorter period of time.

To know more



Krivodol Municipality - Vratsa District

Dr Tzvetan Iliev

+359 9117 2545

+359 9117 2369



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