Welcome to the official Release Notes of the Hysopt product portfolio. This page gives you a concise overview of all updates to the Hysopt product portfolio.

If an update is only applicable to a specific Hysopt product, the update is marked with the corresponding product label (e.g. SIMULATOR-ONLY, CALCULATOR-ONLY ).
All other updates are general software improvements available to all users.

For the Hysopt BIM Syncer, updates marked with 🔄️ require an update of the revit plug-in. This newest revit plug-in can be downloaded here.

Hovering over a link now highlights its connected counterpart

• When hovering over a canvas link, the connected target is now automatically highlighted.

• This makes it easier to understand where links connect and how linked elements relate to each other.

• The update improves readability when working with links across the model.

Heat meter box extended with input/output connectors SIMULATOR-ONLY

• Added input and output connectors to the heat meter box.

• Input connectors allow users to add additional heat consumption and heat production.

• Output connectors make it possible to reuse the aggregated consumption and production elsewhere in the model.

Upgraded model settings interface with cleaner layout

• Refreshed the model settings dialogue with a cleaner and more balanced interface.

• Navigation tabs are now arranged in a left-hand ribbon, with the selected settings displayed on the right.

• The upgrade also applies to the default model settings window in the user preferences.

• The new layout improves readability and provides more room for future extensions.

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New interface of the model settings window

Hysopt Search now opens with Ctrl+F

• Added a new hotkey (Ctrl+F) to open the Hysopt Search directly.

• The Hysopt search allows users to quickly find specific objects or object groups in the current model.

Added heating/cooling and changeover layers

• Added a heating/cooling layer and a changeover layer to Hysopt.

• These layers can now be temporarily hidden to focus on specific parts of the model.

• The feature is especially useful on crowded floor plans with overlapping systems.

• Hidden layers are also excluded from exports, making it easier to create purpose-specific views.

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From crowded schematics (left) to streamlined views (right) using layers

Minor UI updates and bug fixes

• Updated the zoom-to-fit hotkey to Ctrl+Shift+F.

• Improved messaging when no suitable part from the selected catalogue could be found. CALCULATOR-ONLY

• Completed translations in the IES data file upload window. SIMULATOR-ONLY

New pipe graphs for looped networks and data centres SIMULATOR-ONLY

• Added new graphs to pipe objects for flow velocity and pressure loss per unit length (Pa/m).

• These graphs are especially useful for designing and validating data centre networks, as well as other looped networks.

• The new graphs help analyse systems where bidirectional flow through pipes can occur, depending on the current pressure equilibrium in the network.

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Demo usage of new pipe graphs

IES data upload released in thermal load generator SIMULATOR-ONLY

• You can now upload data files exported by IES directly in Hysopt.

• This enables a smooth integration between IES and Hysopt when generating thermal loads.

• The update reduces manual data handling and helps streamline the workflow between building simulation and Hysopt modelling.

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IES Data upload on the thermal load profile generator

Solver improvements for faster simulations SIMULATOR-ONLY

• Upgraded the calculation solver to improve simulation performance.

• The improvement is most noticeable in large models.

Minor UI updates and bug fixes

• Improved error highlighting for simulation models with loops in the control logic. SIMULATOR-ONLY

• Beta features have been officially released and are therefore no longer shown in the user preferences.

Extended the Belimo catalogue with characterised control valves CALCULATOR-ONLY

• Added Belimo characterised control valves to Hysopt.

• The new catalogue parts are available on two-way and three-way control valves.

• Based on Hysopt’s valve authority algorithm, the corresponding Belimo valve can be selected automatically

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Extended Belimo catalogue in Hysopt with 2-way and 3-way control valves

Added smart delete BC (Ctrl+Del) which preserves pipes/ducts

• Introduced a new operation smart delete BC (keep connections), available via Ctrl+Del.

• This feature replaces the deleted BC with a node, ensuring connected pipes or ducts remain in place.

• Added warning messages for scenarios in which the smart delete BC (Ctrl+del) cannot be applied.

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Demo of the smart delete BC (keep connections) using Ctrl+Delete

Minor UI updates and bug fixes

• Improved error handling when using part selection (catalogue) on the ePICV while having parameters locked. CALCULATOR-ONLY

• Improved the implementation of the secondary heat flow limit on ideal production SIMULATOR-ONLY

• Resolved issue where sensitivity variants got stuck occasionally SIMULATOR-ONLY

Upgraded the search bar for better element search

• Search results are now more transparent, helping users understand why specific elements appear in the result list.

• Additional context is shown directly in the search interface, making it easier to distinguish between matches on names, identifiers, labels, and other element properties.

• Users can navigate large technical studies more efficiently by quickly identifying the most relevant search result.

• This improvement builds on the recent component identifier and component label functionality, making structured model navigation more powerful

Canvas label toggle added to report exports CALCULATOR-ONLY

• Added a toggle when exporting component, installation, or pump reports to include or exclude the canvas label column.

• This allows users to create cleaner report exports when canvas labels are not used, whilst preserving compatibility with workflows that still rely on the previous canvas label identification logic.

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Demo usage of the Include canvas labels toggle when exporting reports

Minor UI updates and bug fixes

• Added safety mechanisms to prevent standalone dynamic labels from being copied, avoiding unstable “No label” text objects.

• Improved the system check for pump placement around the hybrid production BC “Hydraulic separator with parallel production”.

• The Belimo Energy Valve and Belimo EPIV are now available in Hysopt as catalog on the ePICV base circuit.

• Hysopt can automatically select the correct Belimo part based on your design requirements

• The update allows for much faster Belimo component selection as the selection happens all at once on a model level

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Demo usage of the new Belimo catalogue on the ePICV BC in Hysopt

BC auxiliaries now scale correctly on floor plans

• Improved the scaling behaviour of BC auxiliaries on floor plans, more specifically the lock icon, connector nodes and control connectors.

• These BC auxiliaries now correctly scale together with the Base Circuit scaling operation (hotkey: Alt + + and Alt + -).

• The update helps avoid visual overlap and improves both model readability and schematic export quality.

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Zoom in/out base circuits on floor plan

Improved pump head calculations with catalogue components CALCULATOR-ONLY

• Improved pump head calculations when Hysopt performs a part selection from a manufacturer catalogue.

• The pump head calculation now consistently takes into account the properties of the selected part.

• Minor changes to existing pump head results may occur when part selection is used with PICVs and ePICVs.

Improved pump head robustness in changeover edge cases

• Improved the robustness of pump head calculations in specific changeover edge cases.

• The resolved edge case occurs when the critical pressure path is found in one mode, while the critical volume flow rate originates from the other mode.

• The calculation now correctly accounts for the mode of each quantity in the pump head calculation.

• Changes to existing pump head calculations are not expected, but minor differences may occur in specific edge-case configurations.

Upgraded the Hysopt search user experience

• Improved search handling to provide a smoother user experience.

• Search now also supports component IDs and component labels.

• Added different search types ('search by') for a more tailored search operation

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Canvas labels are re-introduced in reports CALCULATOR-ONLY

• Re-introduced canvas labels in reports.

• The canvas label refers to the regular text label placed closest to a specific BC on the canvas.

• This label is linked to the BC in the report through the Canvas label column.

• The update ensures backwards compatibility with older technical studies, with canvas labels being complementary to the newer component ID and component label.

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Example usage of canvas labels in reporting

Minor UI updates and bug fixes

• Resolved system check issue when using an ePICV instead of a PICV at an end units in changeover.

• The displayed efficiency of thermal energy source BCs is now correct in all situations, including simulations during which the system was mostly deactivated. SIMULATOR-ONLY

• Updated the default Kvs series of 2-way and 3-way control valves to better align with manufacturer series. Minor changes in selected Kvs values may occur. CALCULATOR-ONLY

• Updated the ePICV minimum required pressure not reached warning in changeover situations.

• Improved the handling of the repetitive BC scaling pop-up dialogue when using Alt++ or Alt+-.

New BC: passive mixing with ePICV

• A new distribution circuit has been added to the heating and cooling library: passive mixing with an ePICV.

• This BC extends the available options for modelling pressure-independent control in heating and cooling systems.

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Example usage of the new passive mixing with ePICV

New BCs: thermal energy source for cooling and changeover

• Two new production unit base circuits have been added to the library: thermal energy source for cooling and for changeover.

• These represent generic thermal sources and are suitable for modelling waste energy or district heating/cooling connections.

• Both heat consumption and cold consumption are fully integrated in the pareto reporting for a comprehensive energy analysis.

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Thermal energy source BCs are now available for heating (left), cooling (centre) and changeover (right)

Improved pump calculations and pump reporting for changeover CALCULATOR-ONLY

• An inconsistency between the pump head in the application and the pump report export has been resolved, ensuring consistent results.

• Support has been added for different Kv-values for heating and cooling valves on all changeover merger base circuits, improving calculation accuracy.

• Note: existing changeover models may show minor changes in calculation results following this update.

Minor UI updates and bug fixes

• Resolved issue where interaction with deltaT closed the user preferences window unexpectedly on small screens.

Added component identifiers and labels for better reporting CALCULATOR-ONLY

• Added an identifier and label parameter at component level.

• Besides the existing BC identifier, users can now define identifiers and labels for individual components.

• Component identifiers and labels are included in report, improving reporting and documentation workflows.

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Example usage of the new component identifier and component label

Simulation Quickstart now supports more heat demand methods

• Upgraded the Simulation Quickstart wizard with additional heat demand methods.

• The wizard now supports zonal models, generic load profiles based on outdoor air temperature and the existing external data upload method.

• The new heat demand methods are available across all use cases.

• This makes it easier to start simulations from different types of heat demand input.

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Added support for multiple heat demand methods in the simulation quickstart wizard

Upgraded the default model settings in user preferences

• Improved the UI and overall user interaction of the default model settings window

• Users can now load default model settings from the current model

• Users can now also apply the configured default model settings to the current model

• Default model settings also got a better placement in the user preferences ribbon

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Upgraded version of the default model settings in the user preferences

Extended graphs and simulation values of thermal energy source SIMULATOR-ONLY

• Extended the integration values and graphs of the thermal energy source for heating.

Heating and cooling end units are now available in reports CALCULATOR-ONLY

• Heating and cooling end units (radiators/cooling units/…) are now defined as separate components

• As a result, these components are now also available in the component and installation report.

Introducing DeltaT: AI inside Hysopt

• Added Hysopt DeltaT, the new HVAC Copilot inside Hysopt, giving you instant answers, guidance, and engineering knowledge without leaving your workflow.

• DeltaT is built on years of real engineering know-how and insights from 500+ HVAC projects, making its answers practical and relevant to HVAC modelling.

• Helps you find information faster, understand modelling choices, and continue working without interrupting their design process.

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Demo usage of Hysopt DeltaT

Launching duct sizing in the ventilation library

• Extended the ventilation library with duct sizing design capabities.

• The duct sizing algorithm can quickly size complete duct systems based on air velocity or pressure loss constraints.

• Added extensive model settings which allows full customisation of the duct catalogue (material types, circular dimensions and rectangular dimensions).

• Ducts can also be placed on floor plans, where their lengths are automically calculated

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Duct sizing is now available in Hysopt

Default model settings are now fully customisable from user preferences

• Added new functionality in the user preferences to fully tailor default model settings to your workflow.

• Default model settings are automatically applied to all newly created models.

• You can configure preferred materials, pipe and duct design rules, unit settings and diversity standards once, and reuse them across future models.

• This feature helps standardise your project setup and reduces repetitive configuration work.

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Default model settings are now fully customisable in the user preferences

New thermal energy source BC for heating

• Added a new generic thermal energy source base circuit to the heating library.

• The production unit uses heat as its energy source and is fully integrated with pareto reporting.

• This base circuit can be used to model heat network connections, waste heat recovery, or other externally supplied thermal energy sources in Hysopt

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Example usage of the new Thermal energy source in the heating library

ePICV upgraded with more guidance and flexibility

• Upgraded the electronic pressure independent control valve (ePICV) with better guidance and more modelling freedom.

• Added a distinction between the design flow rate and the maximum simulation flow rate to give more control in simulation, while keeping system design consistent

• Added extra warning messages when the system design does not provide sufficient pressure across a specific valve instance

New BC: electronic pressure independent control valve (ePICV)

• Introducing the electronic pressure independent control valve (ePICV) for heating, cooling, and changeover applications.

• The ePICV combines flow control and dynamic balancing in a single component, using electronic control to maintain a target volume flow rate.

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The new electronic pressure independent control valve (ePICV) in the Hysopt library

Improved transparency of heat pump design data in the parameter list and dynamic label

• Heat pump design data is now displayed more transparently in both the parameter list and dynamic label.

• The dynamic label, as well as the condenser and evaporator output parameters, now also take into account locked design conditions.

• Tip: Use “Optimise system components” to process new input data and update the parameter list, providing clearer insight into the heat pump’s design capacities.

DHW tanks upgraded with cold water temperature override SIMULATOR-ONLY

• Added a cold water temperature override to all DHW tanks in the Hysopt library

• Provides more flexibility in defining boundary conditions for domestic hot water simulations.

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Example of the new domestic cold water temperature override

Improved design guidance for shunt emission BCs

• Added new warning messages to improve guidance when configuring shunt emission base circuits.

• The warnings are triggered when gate 2 conditions exceed the propagated conditions to gate 1, indicating that the “full load from gate 3” propagation is not respected.

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New warning messages on shunt emission base circuits

Minor UI updates and bug fixes

• Resolved column misalignment in the component and installation report CALCULATOR-ONLY

• Beta IES data upload: Introducing the ability to define the application type of the data. BETA RELEASE SIMULATOR-ONLY

Introducing load validation to quick-validate simulated results SIMULATOR-ONLY

• Load validation is now available on room controllers and heat flow controlled end units.

• The new feature provides instant feedback on the load fulfillment of your simulation.

• Any issues are flagged through error/warning messages, along with a new error detection plot that highlights periods with comfort violations.

• Load validation allows system defects to be identified early in the project and provides a clear starting point for resolving the unexpected system behaviour.

• More information can be found at load validation

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Load validation on heat flow controlled end units (top) and room controllers (bottom)

New hybrid emission BCs: shunt emission on supply and return

• Added two new base circuits to both the heating and cooling libraries.

  • Shunt emission on supply

  • Shunt emission on return

• These base circuits are particularly useful in combination with ambient exchange for managing excess heat or excess cooling

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New hybrid emission base circuits: shunt emission on supply or return

Upgraded the building simulation quickstart wizard

• The Building Simulation Quickstart (BSQ) wizard now opens automatically when creating a new model.

• Added a user preference setting to enable or disable automatic opening of the wizard.

Expanded the BC guidance across the Hysopt library

• Extended BC guidance to a wider range of base circuits across the library.

• The BC guidance brings you instantly to the corresponding wiki page

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Example of BC guidance button that brings you directly to the corresponding wiki page

Improved unit handling of power and energy parameters

• Improved decimal input handling for heat flow parameters across all units.

• Enhanced the unit behaviour of energy parameters for better consistency and usability.

Minor UI updates and bug fixes

• Improved the overall stability of PI controllers SIMULATOR-ONLY

• Added a new graph “time at saturation” to all PI controllers to facilitate manual load validation in generic scenarios. SIMULATOR-ONLY

Upgraded W/W heat pump base circuit

• Added a new Design configuration parameter to specify whether the heat pump should be sized using heating or cooling design conditions.

• Added additional output parameters to clearly display the heating capacity and cooling capacity of the heat pump at all times.

• These improvements make the sizing appraoch and resulting performance of the heat pump more transparent during modelling.

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Updates to the water/water heat pump design

New humid air properties BC variant SIMULATOR-ONLY

• Added a new variant of the humid air properties base circuit.

• This variant uses dry-bulb temperature and relative humidity as input parameters.

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Example usage of the new humid air properties BC variant

Improved template replacement algorithm

• Improved the automatic placement of templates when replacing components.

• Added option to insert templates on new canvasses instead on the active canvas

• Improved the pre-filtering of energy centre options in the template configuration screen.

• More information is available on template configuration window

Added non-return valve BCs in changeover library

• Added non-return valve base circuits to the changeover library.

• Two variants of the non-return valve are now available in this library under “distribution circuits”

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New non-return valves for changeover library

Enhanced Mollier diagram on AHUs

• Improved the Mollier diagram and psychometric chart visualisation on all AHUs.

• The legend now includes clear numbering for each legend entry

• Added the enthalpy axis to the charts

• Implemented several minor UI improvements to enhance readability and usability.

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Example usage of the enhanced mollier diagram

Launching the Building Simulation Quickstart (BSQ) wizard

• Introduced the new Building Simulation Quickstart (BSQ) wizard to significantly accelerate model setup.

• Enables automatic generation of common header configurations.

• Optimised for enabling fast processing of importing building simulation data in Hysopt.

• More information can be found at Building Simulation Quickstart

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Example usage of the building simulation quickstart wizard

Introducing the template replacement functionality (Ctrl+P)

• Auto-insert templates in your system using the new template replacement functionality (Ctrl+P)

• The functionality automatically inserts energy centre templates at the location of placeholder BCs

• Relevant control connections are made automatically, reducing the need for manual template setup

• More information can be found at Template Configuration window (Ctrl+P)

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The template configuration screen (Ctrl+P)

Added energy centre placeholder BCs for early-stage simulations

• Added new energy centre placeholder base circuits (BCs).

• Intended for use in early project phases when the final production setup is not yet defined.