Heating and air conditioning controls

Principle

Heating and air conditioning are the two biggest consumers of energy in your hotel. To keep energy consumption at a reasonable level, temperatures must be regulated according to actual needs and occupancy in different zones within the hotel. It is very important that each guest room be equipped with thermal controls.

Explanations

The table below gives recommended temperatures, depending on occupancy:

Heating and air conditioning / Temperature regulation / Application
Normal heat level / 20-22°C / Occupied areas
Low heat level / 16-18°C / Not occupied for a short period
Minimum heat level / 12-14°C / Not occupied for a long period
Normal cooling level / 25-26°C / Not occupied for a short period
Low cooling level / 27-29°C / Not occupied
Minimum cooling / 30-32°C / Not occupied for a long period

Technical solutions can help you regulate temperature efficiently:
• With individual thermal control devices (e.g. radiators equipped with thermostats) customers can regulate room temperatures to suit their needs.
• Automatic control systems can also be used to switch on or off heating and air conditioning in rooms:
- Control systems based on room occupancy can be used to isolate certain rooms, or automatically heat them to a set temperature, when customers enter or leave their room, or pick up their key at the reception desk,
- Automated systems can also be used to shut off heating or cooling when windows are opened.
• Timers or programmers are suitable for reception areas and restaurant rooms, where the ambient temperature rarely needs to be at the highest comfort level.
• Programmable thermostats with a memory (a combination of thermostat and timer) can retain two or more temperature levels for times when less heating/cooling is needed, i.e. at night or when rooms are not occupied. They can also be coupled with presence sensors; when a zone is not occupied, the thermostat set temperature is lowered by a few degrees.
Good building management practices are also essential to proper temperature regulation. These practices include:
• Manual temperature regulation according to zone occupancy (if automatic thermal controls are not installed),
• Appropriate room attribution; heating concentrated in specific zones in winter.

General observations:
• If an establishment is equipped with individual radiators for heating, thermostats can easily be installed on these radiators by a technician.
• Automatic regulation can be put into place by installing an independent regulation system in each room, or a central computerised system. • Automatic heating controls can also be integrated into a building energy management system, if there is one. In this case thermal regulation by zone is recommended, when possible, to optimise the use of heating and air conditioning.
Concerning thermostats:
• To effectively regulate temperature, it is important to verify: the accuracy of the thermostat, the proper placement of the thermostat in the room, and appropriate minimum and maximum temperature settings.
Accuracy:
- The temperature displayed by the thermostat must closely correspond to the desired temperature to be maintained in the room. Thermostat calibration can shift with time, and a set temperature displayed as 20°C may in fact correspond to 18°C or 22°C. It is recommended that you check the temperature at which your heating or cooling starts up, by measuring the actual temperature with thermometer.
- The accuracy of the thermostat trigger settings (the temperature difference between the moment the thermostat starts up the heating and the moment it is switched off) is also important. If this amplitude is too wide, temperatures in the building will vary strongly, and energy will be wasted.
As a general rule modern thermostats are equipped with electronic sensors and are very accurate. Older thermostats use thermocouple (two metal strips) devices and are sometimes less precise.
Position: To ensure the best temperature regulation, thermostats should not be installed next to the door. Make sure they are positioned in a place where guests will see them, and post simple instructions on how to regulate them.

Concerning thermostatic radiator valves:
• Thermostatic radiators are not very accurate, and must be calibrated fairly regularly to ensure a precise temperature setting. To obtain more precise regulation, a group of radiators can be connected to a single circuit via a motorised valve linked to an electronic thermostat.
• Make sure the valves are easily accessible to customers and that they are in proper working order. Provide instructions on their use in the information pack given to customers. Ask cleaning staff to set radiators at a predefined level for new guests.
Concerning timers and programming devices:
• Consider using timers and programming devices, and set them appropriately. Check these setting regularly, at weekends, holidays, and when clock times are adjusted for daylight savings (summer time/winter time).

Implementation

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Costs

Approximate cost:
• variable.
Approximate payback time:
• Possibly < 1-3 years.
It should be noted that costs and payback times are highly dependent on the local setting and the initial situation of the hotel.

Examples

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Benefits

Cost savings
Energy savings:
Installing independent temperature controls in rooms can save up to 30% of heating energy consumption.
• Remember, a savings of 10% can be achieved when the set temperature is lowered by 1°C.

Comfort improvement
Customer comfort:
• Effective temperature regulation will make customers more comfortable.
• Independent temperature controls allow customers to regulate room temperature to suit their needs.

Reduced CO2 emissions
• For a hotel of 1,000 m² that uses 77.5 kWh/m² of natural gas heating annually, and applying emission factors for France, a 35% savings in energy consumption represents:
4.48 t CO2 eq of avoided emissions each year
Emission factors for electricity in France: 84.3 g CO2 / kWh.
Emission factors for natural gas in France: 331 g CO2 / kWh (Source: ADEME).

Constraints

Implementation:
• Ease of implementation: Moderate (**).
• Best time for implementation: at the time of installation renovation.
• Relevant initial situation: the hotel rooms are not equipped with thermostat controls and/or the hotel does not have automatically controlled heating and air conditioning systems.