May 21, 2019

The sure solution to reduce costs! The energy upgrading of a building can undoubtedly bring about significant benefits in terms of reducing total usage costs. “Energy upgrading of a building” means all interventions in a building to improve its energy performance, to the benefit of the owner and the environment. It is obvious that the upgrading concerns only existing buildings, since all new buildings will have to meet the minimum energy efficiency requirements laid down in the Energy Performance of Buildings Regulation (KENAK). Let’s take the things from the beginning. “Energy efficiency of a building” according to law 3661/2008 determines the amount of energy actually consumed or estimated to meet the various needs associated with the normal use of the building, which may include, inter alia, heating , hot water production, cooling, ventilation and lighting.

This quantity is expressed by one or more numerical indices which have been calculated taking into account the insulation, technical characteristics and characteristics of the installation, design and location of the building in relation to climatic factors, sun exposure and the influence of neighboring construction, energy production of the building itself and other factors affecting energy demand, including the indoor climate conditions.

How energy efficiency is calculated

For the calculation of the energy performance of the building, account shall be taken of:

1. The use of the building, the desired indoor environment conditions, operating characteristics and the number of users.
2. The climatic data of the building area
3. The geometrical characteristics of the building shell building elements in relation to the orientation and characteristics of the internal structural elements
4. The thermal characteristics of the structural elements of the building shell e. The technical characteristics of the space heating installation
5. The technical characteristics of the space cooling / air conditioning installation
6. The technical characteristics of the mechanical ventilation installation
7. The technical characteristics of the hot water production plant
8. The technical characteristics of the lighting installation for tertiary sector buildings g. Passive solar systems

At the same time, the positive effect of active solar systems and other heat, cooling and electricity generation systems using renewable energy sources (RES), energy produced by CHP, district heating or cooling systems on site or building site (district heating) and natural lighting.

The energy efficiency of a building is then certified by issuing a Certificate recognized by the Ministry of Development or another body designated by it, issued by the Energy Auditor of Buildings and stating the energy performance of a building. This certificate classifies the building in one of the categories A + to H, depending on the ratio of the building’s performance relative to the reference building.

What applies to the Energy Efficiency Certificate

The certificate includes, inter alia, reference values, such as current legal requirements and benchmarking criteria, to enable consumers to compare and assess the energy performance of the building. The certificate shall be accompanied by recommendations for improving energy efficiency in relation to the costs it may entail. Its maximum power is 10 years. If the building is undergoing a major renovation or addition to an extent that affects its energy performance, the validity of the building’s energy performance certificate expires at the time of completion of the renovation or addition before the 10-year period expires.

In buildings with a total surface area of ​​more than 1,000 square metres. which are undergoing major renovation, their energy efficiency is upgraded to the extent that this is technically, functionally and economically feasible to meet the minimum energy efficiency requirements as set out in the Κ.Α.Κ. (Building Energy Efficiency Regulation). These requirements shall be laid down either for the renovated building as a whole or only for the renovated facilities or building components thereof, provided that they are part of a renovation to be completed within a limited time period in order to improve the overall energy performance of the building.

For the rest of the buildings, for the time being, their energy upgrading is not mandatory even if undergoing a radical renovation, however, the benefits that can be gained for the owner are significant because, according to the data from the Ministry of Environment and Climate Change YPEKA), especially in the domestic sector, 73% of the energy consumed refers to heating needs and 27% to electricity consumption.

The steps of energy upgrading

Energy upgrading involves four key steps:

1. Perform an energy audit: This creates the energy footprint of the building. The thermal characteristics of the shell and the electromechanical installations are captured. At the same time, indoor temperatures and consumption (current, oil, gas, water, etc.) should be recorded.
2. Analysis of the collected data and identification of the interventions that can be performed: The most important interventions usually concern the shell of the building (insulation of various types) and the electromechanical data. In addition to this, one or more systems of energy generation from RES can be installed. which can make a significant contribution to reducing conventional energy consumption. Finally, interventions also take place in lighting, so as to optimize the need for shading with the need for adequate lighting while simultaneously exploiting natural light.
3. Preparation of a detailed technical study of the proposed interventions according to KENAK, calculation of the depreciation time and presentation to the customer. Concluding an agreement to execute the selected interventions under the supervision of an engineer and issue a new energy performance certificate.
4. Funding for some or all of the interventions can be done through self-financing but can also be integrated into the Home-Saving Program or the Operational Program Environment and Sustainable Development (ESPEPA) of the Ministry. Finally, an important factor to be taken into account is the behavior of building users in relation to energy consumption.