Effectively manage the temperature within buildings

Effectively manage the temperature within buildings

The ambient temperature in the workplace is essential to ensure that employees feel comfortable and can work in optimal conditions. It should be adjusted according to the activities carried out on site.

Energy consumption for heating can fluctuate depending on the weather and due to air leaks in the building envelope, especially when it’s poorly or not insulated. For more information on ways to improve the building envelope, please refer to the measure Improving the energy efficiency of the building envelope

Definition of requirements

Assessing heating and air conditioning usage optimisation requirements

Optimising a building’s heating can lead to energy savings of up to 10% of total energy costs. Simple adjustment can prevent premises from overheating. In buildings, each additional degree increases heating costs by approximately 6%.

Depending on the type of activity, the minimum recommended temperature are:

• 20 °C for office spaces
• 19 °C for workplaces where tasks are mainly performed while seated
• 17 °C for workplaces where tasks are mainly performed while standing or in motion
• 12 °C for workplaces involving heavy physical labour.

These minimum temperatures must be reached before work resumes.

The maximum indoor temperature should normally not exceed 26 °C, unless when the outdoor temperature is higher.

Glazed surfaces should be designed to prevent excessive solar heat gain in the workplace.

A need for optimisation may arise, for example, when users complain about thermal discomfort or when measured temperatures deviate from the recommended values.

Identifying the solution and checking feasibility

Properly adjust thermostatic valves

Check whether thermostatic valves are defective, dirty or incorrectly set, especially at the beginning of the heating season. This can be identified when some rooms are noticeably too hot or too cold compared to others.

Secure thermostats in public areas

In public areas such as corridors, toilets or showers, thermostatic valves are often subject to tampering. It is possible to limit the temperature range using pins or clips to avoid unnecessary heating.

Bleed radiators

If radiators make noise (bubbling, gurgling, whistling, etc.) or are only partially warm, they should be bled to improve the efficiency of the system.

Adjust the heating curve

If users complain about the ambient temperature, or if night-time temperatures do not drop despite night mode being active, this is often due to incorrect heating curve set.

Lower the flow temperature in general and/or outside operating hours

Check whether the flow temperature can be reduced – it is often unnecessarily high. A high flow temperature outside operational hours (e.g. nights and weekends) leads to heat losses. A hydraulic balancing, carried out by a heating professional, can help reduce this temperature

Insulate pipes and fittings

Poor insulation of heating, hot water and steam pipes leads to significant heat loss.

Implementation of specific measures

Properly adjust thermostatic valves

Ensure that all thermostatic valves in the same room are set to the same temperature. The markings and settings on valves may vary depending on the manufacturer, but the following indicative values can serve as a reference for adjusting room temperature:

• Position 1: approx. 14 °C
• Position 2: approx. 17 °C
• Position 3: approx. 20 °C
• Position 4: approx. 23 °C
• Position 5: approx. 26 °C
• Position *: approx. 7°C (frost protection)

Allow heated air to circulate

To ensure proper air circulation and prevent heat build-up, it is important not to cover the radiator, the thermostatic valve or the perforated radiator cap. If the valve is located in an area where heat accumulates, the measured temperature will be too high and therefore inaccurate. Free air circulation around the radiator helps distribute heat evenly inside the room.

Secure thermostats in public areas

The lower and upper limits are fixed using a pin or clip. Make sure that all the valves in a room have the same adjustment range.

Bleed radiators

The following steps must be followed when bleeding radiators:

1. Turn on the heating and allow the system to heat up fully.
2. Turn off the circulation pump.
3. Wait one hour for the hot air to rise.
4. Turn the circulation pump back on and fully open the thermostatic valves (position 5).
5. Start with the lowest radiator (usually on the ground floor) and work up to the top floor.
6. Carefully open the bleed valve using a square key, while placing a container underneath to collect the water (be careful, the water may be very hot).
7. Close the valve as soon as all the air has escaped and only water is coming out.
8. Check the pressure on the central heating system’s pressure gauge (for every 10 m of building height, approximately 1 bar of pressure is required, plus the supply pressure from the expansion tank to reach the necessary pressure).
9. If the pressure is too low, add water (see the box on heating water quality).

Regulation

Adjusting the heating curve:

• Set the target temperatures (e.g. 21 °C for offices) and identify rooms that are difficult to heat (e.g. north-facing, exterior-facing, top floor or corners rooms).
• Check and analyse the ambient temperature.
  • If the heating curve is set too low, the target temperature will not be reached and users will complain.
  • If the heating curve is set too high, the ambient temperature can be lowered using the thermostatic valve, but a high flow temperature causes heat loss in the production and distribution system (e.g. no night setback or general temperature reduction).
• Correct the heating curve.
  • Lower the flow temperature by 3 °C during the heating period
  • General rule: for radiators, lowering the curve by 5 °C reduces the ambient temperature by about 1 °C and vice versa. For underfloor heating, lowering the curve by 2 °C reduces the ambient temperature by about 2 °C.
  • If the ambient temperature is too low in cold weather (below 0 °C), increase the flow temperature
  • General rule: for radiators, raising the curve by 5 °C increases the ambient the ambient temperature by 2.5 °C, for underfloor heating, raising the curve by 2 °C increases the ambient temperature by 2 °C.
• Adjust the heating limit: lower the limit by 1 °C during transitional seasons, ideally in autumn, on overcast days, and when the outside temperature is between 12 and 18 °C

• Take measurements: record the ambient temperatures during the two weeks following any changes to the heating curve.
• Repeat steps 4 and 5 (adjust the heating limit and take measurements) until the desired temperature is no longer maintained (complaints arise), the adjust settings ​​if necessary.
• Correctly set the temperature via thermostatic valves and record the results as well as the new target values in a logbook.
• Carefully note every change to the heating curve (values ​​before and after modification).
• Inform all relevant personnel of the adjustments made.
• Verify that the outside temperature and the time displayed on the heating control are correct. extérieure et l’heure indiquées sur la commande de chauffage soient correctes.

Baisser la température de départ en dehors des heures d’exploitation

• Dans un premier temps, déterminer les pièces et les plages horaires pour lesquelles la température sera abaissée.
• Abaisser la température de départ de 2 °C maximum sur la commande du chauffage pour les périodes et  pièces concernées (idéalement lorsque la température extérieure nocturne est proche de 0 °C). Documenter tous les changements dans le carnet de bord.
• Observer l’effet du changement pendant au moins trois jours :
  • La température ambiante est-elle respectée lors de l’utilisation ?
  • Y a-t-il des problèmes de condensation liés à un taux d’humidité de l’air trop élevé ?
• Répéter l’abaissement comme décrit ci-dessus jusqu’à ce que la température ambiante choisie ne puissent plus être respectée ou que des problèmes de condensation apparaissent. Dans ce cas, remonter la température de départ avant la dernière baisse.

Lowering the supply temperature outside operating hours

• First, identify the rooms and time periods for which the temperature will be lowered.
• Reduce the supply temperature by a maximum of 2 °C on the heating control for the relevant periods and rooms (ideally when the outside night temperature is close to 0 °C). Document all changes in the logbook.
• Monitor the effect of the change for at least three days:
  • Is the ambient temperature maintained during usage?
  • Are there any condensation issues caused by excessive air humidity?
• Repeat the reduction as described above until the chosen ambient temperature can no longer be maintained or condensation problems appear. In that case, increase the supply temperature back to the level before the last reduction.

Insulating pipes and fittings

All pipes and plumbing (hand taps, valves, pumps etc.) located in unheated rooms should be insulated to prevent energy loss. It is also recommended to regularly check the insulation of existing pipes.

State subsidy application

State subsidies

Application for subsidies from electricity and natural gas suppliers

Since 2015, natural gas and electricity suppliers are required to make energy savings for consumers under the obligation scheme. Since then, energy suppliers have been offering support and advice, as well as subsidy programmes for consumers to implement energy efficiency measures.

The following suppliers offer this service for companies:

• Enovos + SUDenergie
• Sudstroum

N.B. Supplier subsidies can be combined with any state subsidies for the same project.

After the implementation of works

Properly adjust thermostatic valves

Check thermostatic valves annually at the start of the heating season.

Secure thermostats in public areas

If there are changes in the use of rooms, it may be necessary to adjust the limitation mechanism on thermostats.

Bleed radiators

Radiators should ideally be bled every three years.

Adjust the heating curve

Each adjustment of the heating curve should be monitored. Changes depend on feedback from users of the affected rooms.

Lower the supply temperature outside operating hours

When operating hours are adjusted, the supply temperature reduction settings should also be adapted accordingly.

Insulate pipes and fittings

Any changes to technical rooms may result in uninsulated lines or piping. It is therefore recommended to consider this when planning such modifications.

• Occasionally, insulation may need to be removed for maintenance work. In these cases, ensure that insulation is properly reinstated once the work is completed.