The heating requirements of buildings are affected by the condition of the building shell and by the exchange of air. The building shell is divided into the following areas: windows and doors, walls, ceilings and floors.

The greatest heating requirements of a building shell are generally windows and doors because they exhibit 4 to 5 times worse U-values than walls. Windows also harvest solar energy, however, although it cannot always be fully used with large glass areas. Modern or renovated buildings should have insulating glass. The thermal insulation values of external walls are better than those of the external windows, but often the surface area of the walls is 3 to 4 times more than of the windows.

Modern buildings require only one third of the energy of a building from 1975. Also the passive house standard has already been introduced in trade and industrial building.

Ceilings can have very high energy losses depending upon their area proportions to the external wall; therefore they also need to be well insulated. In a two-story building, ceilings can represent 20 - 30% per cent of energy loss. These losses can be extremely reduced by insulating the ceilings: 24 cm of thermal insulation can reduce the losses by approximately 80%.

Floors can become very cold when they are located over garages or passages. In order to prevent cold feet and energy losses, sufficient thermal insulation must be installed here.

The exchange of air is affected by four effects:

• air exchange via a ventilation system

• air exchange via user behavior 

• air exchange via customers (open doors, air traps at the entrances)

• Leakage

Air exchange via a the ventilation system is usually determined by regulations and/or must adhere to employee protection regulations and is usually not flexible. However, air can probably be exchanged outside of the periods of operation and so save operating costs.

 Air exchange via windows and doors can be affected by the user and should be as efficient as possible. Quick ventilation instead of continuously tilted windows is more sensible and saves energy.

Warm air currents consume a great deal of power requirement to avoid the penetration of cold air at entrances during the cold season. Apart from the considerable amounts of heat, they also require substantial electric power to operate blowers.

User behavior

Windows need to be opened consciously and consciously closed. Tilted windows do not cool the adjoining area very intensively; therefore closing the windows is usually forgotten. When this type of ventilation malfunctions, it also vents the room temperatures. Therefore users need to be trained in proper ventilation techniques and other energy-saving behavior.

Immediate measures

• Discuss problems of the heat supply with co-workers and repair defects.
• Evaluate room climate with specialist and set measures (e.g., get to the bottom of a draft and set counter-measures).
• With the specialist, inform workers about user behavior.

 Long-term measures and investments

Renovating a building for energy reasons is often reasonable on a long-term basis. Considering the gain in maintenance and comfort, amortization drops to a bearable period and subsidies add incentive. Measures for to improve the thermal insulation and comfort include:

• Install insulating glass in windows and/or glass doors.
• Arrange showcases as dedicated areas with a buffer function between the interior and the external climate.
• Lead heat from the ceiling to the ground in high areas.
• Avoid hot air currents at entrances; instead plan wind catches with two automatic doors or turning doors.
• Use heat recovery for ventilation systems.
• Install thermal insulation at external walls, ceilings and floors.
• Adapt ventilation systems to their usage.

Future prospects

As energy becomes more and more expensive, therefore a well planned new construction or renovation definitely upgrades the value of your property. Thermal insulation is an investment and saves much on operating cost over the period of operation.

 Source: Austrian Chamber of Commerce