Set point
In the construction industry, the term ‘set point’ (or sometimes set-point or setpoint) typically refers to the point at which a building system is set to activate or deactivate.
For example, a heating system might be set to switch on if the internal temperature falls below 20°C, an extract fan might be set to switch on if the relative humidity in a room exceeds 65% and so on.
Set points can be fixed, adjustable or variable. An adjustable set point might be controlled for example by a manually-operated thermostat. A variable set point might be controlled by some form of calculation, for example, set points for air conditioning systems may be programmed to be higher when outdoor temperatures are higher as people are more conditioned to, and dressed for those higher temperatures. Alternatively, if a building is unoccupied, the set point for the heating might be programmed to reduce to just 5°C to prevent pipework from freezing.
The set point at which something is activated may be different from the set point at which it is de-activated. This prevents continually switching on and off if the conditions are very close to the set point.
Set points may be fine-tuned during the commissioning process, and building occupants may be given control of some set points, perhaps within prescribed parameters.
Set points should be monitored, and checked regularly to ensure that they are correctly set and that they are delivering the required result. Seemingly small changes in set points can have a significant impact on performance and energy use. In addition, some building spaces may house critical operations requiring very specific, closely-controlled set points.
It is important therefore that building operators and occupants are provided with an explanation of set points, their operating ranges, and the impact of adjustments on performance and energy use.
NB Guide to Controls (BG 83/2023) written by John Marrow and published by BSRIA in June 2023, defines setpoint as: ‘An adjustable level of a parameter, such as temperature, humidity or pressure, which a control system aims to achieve.’
[edit] Related articles on Designing Buildings
Featured articles and news
The benefits of engaging with insulation manufacturers
When considering ground floor constructions.
Lighting Industry endorses Blueprint for Electrification
The Lighting Industry Association fully supports the ECA Blueprint as a timely, urgent call to action.
BSRIA Sentinel Clerk of Works Training Case Study
Strengthening expertise to enhance service delivery with integrated cutting-edge industry knowledge.
Impact report from the Supply Chain Sustainability School
Free sustainability skills, training and support delivered to thousands of UK companies to help cut carbon.
The Building Safety Forum at the Installershow 2025
With speakers confirmed for 24 June as part of Building Safety Week.
The UK’s largest air pollution campaign.
Future Homes Standard, now includes solar, but what else?
Will the new standard, due to in the Autumn, go far enough in terms of performance ?
BSRIA Briefing: Cleaner Air, Better tomorrow
A look back at issues relating to inside and outside air quality, discussed during the BSRIA briefing in 2023.
Restoring Abbotsford's hothouse
Bringing the writer Walter Scott's garden to life.
Reflections on the spending review with CIAT.
Retired firefighter cycles world to raise Grenfell funds
Leaving on 14 June 2025 Stephen will raise money for youth and schools through the Grenfell Foundation.
Key points for construction at a glance with industry reactions.
Functionality, visibility and sustainability
The simpler approach to specification.
Architects, architecture, buildings, and inspiration in film
The close ties between makers and the movies, with our long list of suggested viewing.
SELECT three-point plan for action issued to MSPs
Call for Scottish regulation, green skills and recognition of electrotechnical industry as part of a manifesto for Scottish Parliamentary elections.
UCEM becomes the University of the Built Environment
Major milestone in its 106-year history, follows recent merger with London School of Architecture (LSE).
Professional practical experience for Architects in training
The long process to transform the nature of education and professional practical experience in the Architecture profession following recent reports.