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Minimum & Maximum Temperature

In general terms every employer (Cardiff University included) has a legal responsibility under the Workplace Health, Safety and Welfare Regulations 1992 to ensure that "During working hours, the temperature in all workplaces inside buildings shall be reasonable". In practice this means that the temperature in workrooms should provide "reasonable" comfort without the need for special clothing.

The temperature in workrooms should normally be at least 16 degrees Celsius one hour after the declared heating time start. The regulations do not state an upper temperature limit; however supplementary guidance would suggest that employers should endeavour to do all that is reasonably practicable to maintain temperatures to a level not exceeding 30 degrees Celsius.

Cardiff University campus buildings are generally heated to a target maximum internal space temperature of 20 degrees Celsius during the heating season. This is one degree higher than the level specified in the legislative document: Control of Fuel and Electricity (Heating)(Control)(Amendment) Order 1980.

Heating Season

The heating season spans from 1st October to 30th April inclusive.

Should internal space temperatures in September and May fall dramatically lower than average due to abnormal weather conditions, Estates will monitor the conditions and consider if heating is required.

During late May, June, July, August and early September, heating systems are generally being overhauled and maintained in readiness for the heating season so it may not be possible to quickly switch heating systems back on.

Heating Times

Heating times for academic buildings during the heating season are based upon the building being as close to the maximum internal temperature set point as possible for building occupancy between 8:30 – 5pm, Monday to Friday.

Pool rooms, lecture theatres and teaching areas are heated during the heating season to their class booking times once these times are known. Similarly, library areas are heated during the heating seasons to cover their opening times.

Heating outside of these times during the heating season may be considered although there may be a charge made for this to the department/school requesting this option.

Heating Controls

Optimum Start-Stop
The vast majority of the Cardiff University campus is controlled by a Building Energy Management System (BEMS). This entails an optimum start-stop routine that calculates times for the heating to come on at full power to pre-heat buildings prior to the normal start time.
These calculations rely upon both external internal space temperature sensors being operational to enable the heating plant up to four or five hours beforehand, dependant upon the environmental conditions sensed.
Similarly, the heating can go into an “optimum-off” setting later in the heating day if the building is warm enough, again to save energy.

Weather Compensated Heating
Most radiator circuit temperatures around campus are controlled after occupation time by the outside temperature conditions (E.g. If the outside temperature is very low, the radiator circuits will be running at their maximum. This temperature drops as the outside temperature warms up.). This is possible due to the building fabric losses being higher in colder weather.
Many times during mild day conditions, the radiator circuits can therefore appear lukewarm or even cool and this is due to the compensation system working.

Thermostatic Radiator Valves
Thermostatic Radiator Valves (TRV’s) should be considered as almost a fit-and-forget item as they can be set to regulate local room temperatures without the need for turning valves on and off. A recurrent “lack-of room heating” problem that is regularly reported to Estates is that room temperature is regulated by user turning the TRV up to maximum in the morning and then turned completely off in the afternoon…… the TRV is then frequently  left off overnight making the room cold the following morning. Due to this issue, many TRV’s installed over the past few years have been non-adjustable types. It is recommended that where adjustable TRV’s are installed, they are left set in the most comfortable position for each individual user.


Residences are heated to a residential room temperature set point of 21 degrees Celsius and specific residential occupancy heating times are available from the Campus Services Division.

Hot water is provided at a minimum of 55 degrees Celsius to comply with Legionella Regulations and blended at showers/baths to prevent scolding.

Portable Heaters

The use of portable heaters is not recommended as:-

1. They constitute an increased fire risk to the buildings and occupants
2. They can cause false temperatures to be sensed and prevent heating to be enabled
3. The electrical system is not designed for heavy load use such as portable heaters, can cause overload to occur and there is a potential disastrous failure of circuits or even entire electrical systems.
(Previous historic incidents have been recorded whereby entire heating zones have been held off due to high temperatures being sensed in buildings thus preventing heating to other occupants being enabled due to a portable electric heater being left on.)

All portable heater authorised by Estates must have a current Portable Appliance Test (PAT) certificate. Personal portable heaters must not be brought in from home and connected to the University’s electrical system.

Should there be a failure of heating in a building or buildings, Estates will endeavour to provide emergency portable heating if at all practically possible to retain the use of the areas. Individual rooms not attaining the minimum space temperatures should be referred to Estates so that they can be dealt with as appropriate. Should it not be possible to provided temporary alternative heating to areas following a failure of a main heating system then other measures will be referred to the appropriate senior officers of the University.

Portable heaters on hospital maintained premises are not permitted by the local health board.