CIBSE Domestic Heating Design Guide (2026)

Please note hard copies won't be available for delivery for 2-3 weeks.

The new edition of the Domestic Heating Design Guide responds to a rapidly evolving heating landscape by improving technical accuracy, accountability, and system performance, while aligning with current regulatory expectations, including the Building Safety Act. It introduces the System Criteria Document to provide a clear, auditable record of design decisions, system intent, and professional responsibility. The guide updates heat loss calculations using the latest CIBSE weather data and closer alignment with BS EN 12831-1, adds dedicated guidance on control strategies, revises domestic hot water design in line with BS EN 12831-3, and expands coverage of modern hydraulic and system configurations.

The new edition incorporates the following: 

• Addition of visual flow diagrams for ease of use 
• Addition of a new System Criteria document that could record all design decisions, aid in commissioning and encourages the client and designer to sign-off, in line with the Building Safety Act 
• Incorporating the latest CIBSE Weather data with 28 zones and four outdoor design temperatures 
• Addition of Heat loss assessment method as per the BS EN 12831-1:2017 method 
• Updated U-value tables to cover modern construction methods 
• Domestic hot water cylinder sizing method as per BS EN 12831-3:2017, coverage of sizing for storage of DHW at less than 60°C, and thermal disinfection procedure.  
• Controls section with focus on control strategy and additional guidance around mixed temperature systems 
• System Design section with improved coverage of fundamental fluid-dynamics principles, heat emitters other than steel panel radiators), advanced system layouts (such as four-pipe heat generators and manifold distribution), circulator control options, and low-loss headers