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FAQ Energy

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Contact, Courses, Energy monitoring, Energy savings, Individual measures, JLU measures, Lighting, Malfunction report, Operating hours

Last updated 23 November 2023


How much energy could be saved in fall and winter 2022/23 compared to the preceding year?

Due to the uncertainty regarding the energy supply during the winter season of 2022/23, JLU aimed to reduce its energy use by 25 % compared to the previous heating season. Thus, JLU wanted to contribute substantially to secure the energy supply in the region. The main objective was to guarantee the operation of the whole university and to avoid a permanent relocation of teaching into digital formats.

The energy savings compared to the previous year for district heating and electricity in the period from September 2022 to June 2023 averaged 20.9 percent. In particular, the prudent behavior of JLU members has contributed to this great result. JLU would like to thank its members for their support.


How much energy does JLU use?

The energy monitoring provides an overview of the heat and electricity consumption of JLU as well as the savings in relation to the period 2021/22.


Are there any restrictions for courses in the winter semester 2023/24?

In the winter semester 2023/24, courses will be held also on Fridays. We would like to remind you that the rooms are heated to 20°C from Monday to Thursday from 8 a.m. to 6 p.m., and Friday and Saturday from 8 a.m. to 4 p.m. We kindly ask you to ensure that the rooms are used to their full capacity from Monday to Friday and to keep room bookings to a minimum at off-peak times and at weekends. This list (in German) shows which rooms are preferred for use at weekends or at off-peak times, unless the event can be rescheduled.


How can I save energy in everyday work?

Correct ventilation

Tilt ventilation does not achieve substantial ventilation effects but contributes to the loss of more than 25 % of the heat energy through the windows. Instead, it is recommended to provide your office with fresh air by using shock ventilation two or three times per day (in winter 5, in summer up to 30 minutes). During shock ventilation, your heating element should be turned off so that energy is not unnecessarily lost.

Optimized heating

During the heating period, the ideal room temperature for offices and seminar rooms is 19 to 20° C, which usually corresponds to a heating thermostat level of 2 to 3. Please make sure to turn down the thermostat to level 1-2 in cases of longer absence, especially before weekends. Please do not set them to level 0 (where available) to ensure frost control.

Please take care that heaters are not blocked or covered by furniture, claddings or curtains, in order to ensure that heat can freely circulate in the room and is not retained. Dust and dirt on heating elements are also reducing the heat release.

Use of PC/laptop:

By adapting your use of PCs and laptops marginally, you can save energy: lower the screen brightness and prefer the sleep or energy saving mode to the screen saver during short absence. Bookmarking frequently visited web pages avoids the energy-intense request of search engines. You can also look for climate friendly search engines that might replace your present one.

Emails and videoconferences

If possible, avoid sending large email attachments. Alternatively, you can upload your file to a network drive (winfile) or the 'Hessenbox' and send the corresponding link. Deactivating the webcam during videoconferences has high energy saving potential. You might, for example, deactivate the webcam after saying hello if you are not currently speaking.


Printers need much energy to raise their temperature. Therefore, try to execute several print jobs in a row instead of printing several single pages more often. Perhaps you can even abstain from some of the print jobs. The eco-mode saves energy, toner and ink by printing pages more rapidly. Furthermore, you can save resources if you use recycling paper and duplex print option.

Turn off devices and light

During standby mode, electric devices still need substantial amounts of energy. When devices are not in use, they should be turned off. When leaving the room, and especially in the evening and before the weekend, please make sure that equipment (light, electric devices, ventilation) is turned off.

Check your stock of eqiupment

Get an overview of your equipment and check for dispensable devices. If possible, discuss with your team and with your supervisor if you can share for example fridges or printers. You can save energy if you defrost your freezer (compartment) regularly.

Use sunblinds

In summer, sunblinds should be used to avoid that the building gets heated in order to reduce the need for air conditioning.

Use air conditioner efficiently

Even at high outside temperatures, air conditioning and cooling systems, where available, should not be set below 26° C in order to save energy.

Close shutters

Please close the shutters and sunblinds or curtains in your office, especially during cold nights. Particularly for older windows, this substantially reduces the loss of heat and saves heating energy.

Close the doors

To keep the room temperature as constant as possible in winter, please close the doors. This keeps the heat inside the room and ensures that the room warms up faster.

Use the stairs

Use – if possible – stairs instead of the elevator. It saves energy and provides some physical activity during your office hours.

Travel and business trips

You can use the ‘LandesTicket Hessen’ for your daily travel to work or business trips. Especially for business trips, you should also check for digital alternatives. If you need to use a car, you may carpool so that less fuel is needed per person for each kilometer travelled.

Mobile working

The greater use of voluntary mobile working makes it easier to save energy concerning the commute to work. At the same time, voluntary mobile working makes it possible to combine workplaces and thus workspaces. As a result, fewer spaces need to be supplied with energy.

The Sustainability Office has compiled further tips for energy saving here (in German).


Which measures have already been taken or initiated by JLU?

We want to use energy more carefully in teaching and research while raising the corresponding awareness among employees and students. Being a major institution in Giessen and feeling responsible for the region, we want to contribute to a careful use of resources.

The following measures are taken in the winter semester 2023/24 or pursued:

Room temperature

During the heating period, the temperature at workplaces for general office work should not exceed 20 °C during operation hours (Monday to Thursday from 8 a.m. to 6 p.m., and Friday and Saturday from 8 a.m. to 4 p.m.). The extent of building cooling during the warm season of the library, seminar rooms and lecture halls has been reduced. Furthermore, the cooling of laboratories was reduced in consultation with user representatives.


Since several years, JLU successively changes the outside lighting to energy saving LEDs.


The technology of buildings and installations has been optimized and is further optimized.

Awareness raising

JLU further enhances the awareness of users for energy efficiency so that they can contribute to saving energy. In this regard, the Sustainability Office continues its nudging campaign initiated in the winter semester 2022/23, which included the provision of stickers for light switches as well as informational materials via the website and Instagram channel. The provision of an informational video and a podcast on energy are also part of the campaign.

Users of laboratories were informed about the energy-efficient use of the manual operating unit for the air ventilation and the use of the laboratory fume hoods and forced-air cooling via information letters with operating instructions.


Could energy be saved if the number of lamps is reduced or if motion sensors are adjusted towards shorter lighting times?

Shorter lighting times correspond to a higher amount of lighting periods, which are crucial for the wear of the lamps. In a given case, the benefit will be evaluated by comparing the energy saving potential with the potential required expenditure concerning material and staff.


Where can I report malfunctions, e.g. of heaters?

Please use the online form of Department D provided here to report any malfunctions.


Whom can I contact in case of further questions or suggestions for energy saving measures?

For further questions and suggestions, please contact Please note that the processing and corresponding assessment of technical and judicial circumstances will take some time. We therefore ask for your understanding that we are not able to inform if and when your suggestion is going to be implemented.

Students may also contact studieren with any teaching-related concerns.

We thank you very much for your help in saving energy!