Building Energy Modeling Software

for busy consulting engineering firms

Building Energy Modeling Software

for busy consulting engineering firms

Tas Engineering is an industry-leading building modeling and simulation tool capable of modeling the world’s largest and most complex buildings

The complete thermal simulation solution

HVAC Modeling

Robust, component based plant modeling


Helpful tools which do the hard work for you

Natural Ventilation

Fast & fully integrated natural ventilation

Daylight Analysis

Fully integrated into the software

Generic Optimization

Parametric & Optimization

HVAC simulation using Tas Systems

Component Based

Tas Systems is a Component based plant modeling tool with a drag and drop interface.

Fully Customizable

Every component has editable properties with fully customizable control logic.

Schematic Design

Plant models are laid out to resemble HVAC schematics for clarity.

Template Systems

Optional wizard to walk users through setting up common system types.

Assisted setup through the systems wizard

Tas Systems includes a project wizard which can optionally be used to create a range of typical setups which can then be further edited if desired. The prepared airside systems include but are not limited to; fancoils, CAV & VAV systems, VRF, chilled beams, and PRM Baseline systems for 90.1 versions 2007, 2010, 2013, and 2016. Waterside systems available through the wizard include but are not limited to CHP and ground source systems.

Create and control bespoke systems

Fully customizable controls allow a wide range of component behaviour to be modeled.  Even very complex systems can be easily modeled and any system can be added to the library for use on future projects.

Full control

Systems can be edited as required to match the real-life setup or to test designs. The component library contains a wide range of equipment with fully editable properties.  Custom profiles can be applied to many of these properties to control the equipment, for example the the efficiency of a component could vary with air temperature.
  • Import manufacturer data to components
  • Assisted calculation of component efficiencies for 90.1 baseline systems
  • View results on schematic, in graphs, or tabular format
Our help documentation includes detailed guides to the components and controls
Reports can be easily generated as PDFs or Excel spreadsheets. The report generator is a great way for the user to extract the desired results in an easily interpreted and accessible format over the time period of interest, be that annual, monthly, daily or hourly.

Co-ordinate your project

Tas Systems is fully integrated with the other components of the Tas package and results can be imported from multiple simulation files.  This allows engineers to work concurrently on different parts of the building then merge their results together to work on the HVAC.

Case Studies


140-1 compliant software for 90.1 versions 2007-2016


Tas Engineering includes a 90.1 studio which does all the hard work for you, generating baseline building geometry and lighting gains for 90.1 versions 2007 and 2010 as well as providing tools for calculating efficiencies for baseline equipment based on sized capacity, fuel type, climate zone, etc. 


Tas is compliant with ASHRAE 140-1 2014, 2007, and 2004, as well as being a qualified 179D software for Tax deductions.

Baseline systems generated and efficiencies calculated

Our studio tools automate the process of setting efficiencies for fans, heat exchangers, boilers, chillers, and heat pumps, and the calculated efficiencies are displayed clearly to the user.  Throughout the software, units of measurement can easily be switched from SI to IP & vice versa.

Daylight Simulations

Climate Based Daylight Modeling

Multi-core distributed Climate Based Daylight Modeling for rapid design iterations.

Daylight Factors

Fast daylight factor calculations using a radiosity engine for accurate results.

Daylight Rendering

Render a high quality 3D view of your building at any hour of the year to see how it will look.

Right to Light

Equivalent First Zone, Daylight Distribution, Vertical Sky Component, Permanent Overshadowing.

Tas Generic Optimization

A utility for parametric simulations & variable optimization

TasGenOpt intelligently combines GenOpt from Lawrence Berkeley National Laboratory with a powerful c# scripting interface in order to achieve incredible flexibility and design options. This utility allows parametric runs as well as an optimization facility


Sometimes, it’s easy to understand the effect of a variable on your building: Increasing the boiler efficiency results in a reduction in CO2 emissions. Other times, it’s not so clear.

Imagine adding more insulation to your external walls – the U-value will decrease and the heating demand will decrease, but this may have some other effects:

  • Increased risk of overheating
  • Increased cooling demand

With some variables, there is an optimum value that balances the effects a variable has. One way to find this optimum value is to perform many simulations with different values, but this can be slow and time consuming. 

TasGenOpt solves this problem by doing the hard work for you, automatically minimizing the number of simulations required to find the optimum value.

Parametric runs

Simply select the parametric option, and the program will dynamically change your input variables in the range you specify, notify you once it’s done  and output the results visually.  

Multiple variables

There is no limit to the number of input and output variables using TasGenOpt. This means you can balance everything from the angle of the shades to the aperture dimensions and openable proportion and minimize energy consumption whilst maximizing thermal and visual comfort. 

Or adjust the shades on a classroom to get the best daylighting result. With daylighting, it’s important to make sure the space isn’t too bright or too dim, so a careful balance of the parameters is needed.

Get started quickly

In order to get started quickly, TasGenOpt has a number of useful resources:

  • Reusable Script Library
  • Example Scripts
  • Detailed Documentation 
  • Skilled Technical Support

Reusable script library

TasGenOpt has a library of useful scripts that you can expand and share with others. This can save valuable time on future projects. 

Example scripts

TasGenOpt comes with example scripts demonstrating how to perform common tasks, and each has detailed comments explaining what the script does and how it works 

Detailed documentation

Not only does the TasGenOpt documentation explain how the software works, it also includes a series of detailed ‘walk through’ examples that will introduce you to the basic concepts and lead you to solve your first optimization problem.

Skilled technical support

Our entire support team works very closely with our software developers and as a result, will be able to provide the very best advice for writing optimization scripts. 

Comfort Analysis

Assess the expected comfort levels in your design

  • Overheating Potential
  • Radiant Environment
  • Perceived Comfort
  • Fresh Air Levels
  • Clear & helpful results viewer

Data Import & Export


2D DWG import allows tracing of new geometry, and 3D DWG shade surface import allows easy modeling of complex shading.


Tas intelligently repairs common issues with gbXML geometry.


Exchange data with EnergyPlus. Import or export geometry, building fabric, gains and schedules, and even import shading data for a ready-to-simulate building data file.​


Import geometry, building fabric, and internal condition data from DOE-2 INP files.

SI & IP Units – Its just a simple switch between units of measurement

Tas has a multitude of data import & export options enabling it to be an integral part of a BIM workflow.

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