An energy audit is a procedure that determines how energy is used, the possible energy conservation measures, and how energy can be used more conservatively on the audit site.

An energy audit provides an overview of the technical status and energy losses in a building. An audit highlights priorities for renovation along with energy conservation and payback period calculations.

An energy audit can be viewed as a part of the investigations into the state of a building, the goal of which is to determine the building’s energy-related and technical situation. An energy audit is a useful diagnostic tool that allows a long-term renovation plan to be put in place.

An energy quality notice, building energy certificate or corresponding energy performance label can readily be prepared on the basis of audit reports. These documents are of value when a building is sold.

The energy audit results in a list of energy conservation measures to achieve energy conservation in a building. By implementing the recommended energy conservation measures, the proprietor of a building can reduce expenditures made on energy and other articles.

An energy audit may be a requirement in applying for a loan for renovating a building.
In the future, reducing emissions of CO2 will prove increasingly important. Energy audits can be one tool in finding opportunities to reduce CO2 emissions.

A thorough energy audit of a building should include:

• investigation of pipes and heating, ventilation and air conditioning systems. 
• structural investigation
• investigation of electrical or automated systems
  

The energy audit report consists of the following components:

• description of the building
• data on the building
• technical state
• energy-related state
• table offering applications for problem parts of the building along with monetary cost and payback period

Calculation of a building’s energy consumption and energy conservation measures starts with a determination of heat retention, use and expense.

The local climatic conditions (degree-days) and construction standards for the building are specified in the project definition. These are adjusted after the audit with U-value parameters derived from actual heat consumption. After the data are standardized, changes derived from the adjustments are made to the values and the potential savings are calculated.

This procedure is repeated separately for each of the following four basic operations: ventilation, water, electricity, external influences.

The result obtained is the energy balance basic data.
The energy balance data obtained are fed into accounting software and the cost and payback period for the energy conservation measures are calculated. If the payback period exceeds the permitted limits, the values for various basic operations are changed until a list of energy conservation measures suitable for the client's budget is achieved.

Thermography

Energy audits often come into play in connection with a requirement or desire to have thermal imaging or thermography performed.

The basic goal of thermal imaging of a building is to establish heat leaks and inspect the quality of walls, windows and all sorts of joints and seams in the building. It is also possible to use a thermal camera (Thermovision) to find cold bridges within walls.

If a building’s heating bills are high and the temperature does not conform to what is desired, it is a good idea to conduct a thermal inspection of the building shell in order to prepare a renovation plan. Precise mapping of leaks helps to avoid the need for full insulation of the building shell.

The result of the proceedings is a report including an infrared image that shows leaks and a digital picture that makes it easier to perform spot positioning. Each leak is accompanied by a summary describing the nature of the leak and the renovation recommendation. The report is in both hard copy and digital form.