Energy accounting and rehabilitation of community owned buildings

Investigations in Europe show, that public buildings often have worse energy indicators than private buildings. Because of the hugh number of such buildings - in average municipality or state owned buildings are the relative highest share of the local building stock - their rehabilitation and better operation including equipment, maintainance and energy use stimulates the economy a lot. In the minimum it is a question of credibility for the energy policy of a city, that community owned buildings demonstrate a good standard. Meanwhile many European cities have started adequate projects.

A typical projects consists of the following aspects:

• Decision to start the project: It depends on the actual situation and ownership responsibilities, who are the decision makers.

• Explore the base line: Implementation of an energy accounting system, the best on computer (appropriate software is quite developed meanwhile). For each building the energy indicator is calculated through the evaluation of the number of square or cubic meters used in the building and energy demanded for heating, cooling, ventilation, hot water. Other applications for lighting, mechanic work (eg. elevators), communication and computation are investigated separatly. It is recommended to make an additional evaluation report to highlight the purpose of the building, users behaviour, maintainance and other watched circumstances (eg. defect installations).

• Define the target line: Different types of buildings may have different energy indicators depending on their purpose. Higher or lower energy indicators may be justified also under different climate conditions. Usally the provincial regulations give some information about the minimum standards. You can compare these numbers to calculate the energy saving potential. Another method is to fall back on the most energy efficient building you have found during your investigation within each category of buildings.

• Priority setting for rehabilitation: In practice you will start with the easiest measures. In many cases a change of users' behaviour will generate up to 20 per cent of energy savings by simple measures (close windows and doors during heating or cooling devices are working, etc.), set in function devices to regulate temperature, where such devices are not well working or not existing, or organise shadowing at windows, etc. Only now you should consider measures, which need investments to improve the building surface (walls, windows, roofs). Last you should consider exchange and improvements of your technical installations. All measures related with construction and equipment should be arranged with periodical necessary maintainance and repair work to avoid doubling of efforts and costs, where possible. Start with the buildings with the worst energy indicators.

• Financing: Most measures need only to be done. Investment measures should be calculated with respect to the expected energy savings and costs during the rest of the life time of the concerned building and the financing costs of the investment. This investment planning and return of investment calculation is the basis to find, where appropriate or necessary, a third party, who would offer a contracting service under the terms of energy saving contracting. The principle is, that the saved energy costs will cover the investment and the honorarium of the contractor.

• Expected results for the energy system: Investigations in Europe show, that public buildings have an energy saving potential of up to 50 per cent. The market potential is quite lower, but still of a reasonable size (up to 20 to 30 per cent in the average).

• Expected results for the economy: The procurement of building rehabilitation services and works will influence the local industry and labour market. Public sector will save money, which can be invested for other purposes.

• Obstacles to be aware: You want to improve an area, which is considered functioning well and you may interfer with the now responsible persons or institutions. Data collection for energy accounting needs time and professional personnel. Financing through contracting needs suitable partners and professional companies.

• Organisation: Ideally you should convince the administrative body, who is already in charge with the facility management. Some European cities delegate this task to their local energy agency on provision of costs. Who ever will be resonsible has to care for a continuous monitoring of the project and annual updating of the energy accounting.