Load Calculation Software for Enhanced Building and HVAC Design

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IESVE Load Calculation Software for Sizing & HVAC Design

Move up to the best in loads analysis. From optimizing room and zone loads to detailed HVAC system and equipment sizing, IESVE HVAC load calculation software offers the most practical, efficient, and accurate tools available.

Efficiently input 3D geometry, envelope, internal gains, and location for accurate loads calculations.
Include minimum ventilation requirements or choose local code minimum ventilation.
Share reports, gain insights from in-depth results analysis, and iterate on building design.
Transition seamlessly into detailed HVAC system sizing and optimization.

Design Conditions

Establish up-to-date external ASHRAE design conditions from thousands of pre-defined locations.

Construction Materials

Choose from hundreds of pre-configured assemblies or create custom designs from hundreds of material options.

Building Templates

Manage and assign thermal template datasets (setpoints, gains, etc.) to group of room or zones.

Generate Reports

Generate heating & cooling loads reports in spreadsheet and PDF formats.

APACHE: Loads Calculation Methods & Validation

Loads calculations with the world-renowned APACHE engine allows for easy-to-use access to the most robust industry methods, which require (sub)-hourly calculations that account for the storage and thermal mass of construction materials.

ASHRAE Heat Balance Method
CIBSE Admittance Method
Hourly solar radiation, convective & radiative heat gains, thermal mass ANSI/ASHRAE/ACCA Standard 183
ISO 52000 (and DIN EN 12831, BS EN 12831)

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The Mechanical Engineer's Checklist

Our Mechanical Engineer's Checklist walks you through 10 essential criteria to evaluate when choosing a modern HVAC loads and design tool - from calculation accuracy and compliance, to workflow integration and reporting capability.

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HVAC Equipment Sizing & Design Optimization

Airside Systems

100+ Pre-configured HVAC Systems including a range of Baseline options
Single-zone systems (Split systems, DX, Packaged Heat Pumps, CRAC/CRAH, etc.)
Multi-zone Systems (CAV, VAV, DOAS, (In)direct Evaporative Cooling, UFAD, DV, etc.)
Zonal Systems (FCUs, Radiant Systems, Chilled Beams, Series/ Parallel FPBs, Heat Pump & VRF, etc.)
Ventilation calcs for ASHRAE 62.1, ASHRAE 170, CA Title-24, custom parameters, and numerous ventilation, exhaust, and make-up air configurations.
Range of optional controls (Economizer, ERV, HRV, C02- and Occupancy-based DCV, Heat Recovery, Dual-Max VAV, SAT reset, etc.)
A HVAC System Design Wizard for easy configuration of HVAC systems and an automated sequencing of (1) load calculations, (2) equipment sizing, (3) Annual energy simulation, and (4) Generation of reports & schedules
All pre-configured systems can be modified and customized with drag & drop placement of equipment, controls, and airflow paths. Users can also create fully custom systems and edit a broad range of equipment and control parameters.

Airside system modeling in commercial load calculation software.

Plant & Waterside Systems

Pre-configured plant loop examples and customizable loops, including multiple pre-heating, pre-cooling, and heat-recovery options, secondary loops with independently controlled supply temperatures, and scheduled loads.

Heating Hot-Water (HW) with Boilers, Heat Pumps, Electric Resistance, and user-defined heating equipment.

Domestic Hot-Water (DHW) with storage tank losses, recirculation, and pre-heat options including drain-water heat recovery, solar heating, and condenser heat recovery.

Chilled Water (CHW) with air/water-source chillers, heat pumps, and user-defined cooling equipment.

Condenser Water (CW) with cooling towers, wet/dry fluid coolers, condenser heat recovery, and integrated waterside economizer.

Heat Pump (HP) loops with water- and ground-source heat acquisition and heat-recovery options for water-loop heat pumps and water-source VRF/VRV.

Heat Recovery Chiller (HRC) for moving heat from CHW to HW loop.

Thermal Energy Storage (TES) with ice and chilled-water storage tanks.

Controls including constant/staged/variable flow, primary-secondary loop options, supply temperature reset, heat-recovery, staging and sequencing of equipment, etc.

Choose from pre-configured and customizable plant loops in IES loads software.

Plant-Only Simulation

Don’t have a 3-D model? … no problem! ApacheHVAC plant loops can simulate without any 3D model building representation and only requires hourly time-series demand data (e.g. from external metered BAS/BMS sources).

IES Virtual Environment provides a free simple hourly import option from a CSV file which allows for Plant-only simulation in ApacheHVAC, enabling optimization of central plant and/or allowing coupling with energy generation from PV + Battery Storage, all within IESVE Software.

ApacheHVAC plant loop configuration in load calculation software.

Reports and Results

The range of loads & HVAC sizing outputs from IESVE Software include spreadsheets, PDFs and customized visualizations:

Spreadsheet: Heating & Cooling Loads & Airflows
VistaPro Visualization for any room Loads metric
PDF: System, Zone & Room breakdown; boiler, chiller, VRF, DHW, coil & fan sizes
VistaPro Hourly Graph/Table for any HVAC equipment or at any schematic node

Access a range of reports and customized visualizations with IES loads software.

Revolutionize Your HVAC Design Workflow with IESVE

Unlock a faster, clearer workflow, designed specifically for MEP engineers.

Discover our step-by-step workflow for delivering efficient loads, sizing and advanced control strategies.

Watch & Learn Download Guide

Resources

Discoveries

ASHRAE Heating & Cooling Load Calculations

Discoveries

How to Calculate Peak Cooling Loads in Humid Climates

Discoveries

Evaporative Cooling - Energy & Water Performance Modeling

Discoveries

Accurate Load Calculations: High-Performance Buildings in Canada

What our Customers Say

For us, IESVE is our all in one tool for doing loads, energy, daylighting, etc. Doing loads analysis is simple to run especially with the parametric tool in the VE. This tool allows us to test ideas and get results quickly efficiently, and the results are accurate. We now use the VE for all of our projects. On a recent office project, using the VE, we were able to improve glazing, reduce mechanical system size, and save the owner money all through the results of our analysis.

Miles Dake

Mechanical Engineer at ME Group

IES actively listens to and responds to the needs of its customers. Our mainstream design teams have given much deeper commitment to the use of the VE – the VE is not just for our one-of-a-kind high performance “jewel box” projects. We are taking advantage of the much more user-friendly load reports on our everyday work. The graphics and visualization tools built into the VE are making it much easier for our teams to understand and optimize system performance and sizing.

Kim E Shinn

Principal/Senior Sustainability Wizard at TLC Engineering Solutions

Frequently Asked Questions

What functionality does IESVE offer as an HVAC Design software?

IESVE software provides accurate, efficient tools for load calculations, system sizing and HVAC design — covering everything from room and zone loads to detailed HVAC system and equipment sizing, all within a single integrated platform.
What load calculation methods does IESVE support?

IESVE uses the world-renowned APACHE engine to support industry-leading methods including the ASHRAE Heat Balance Method, CIBSE Admittance Method, ANSI/ASHRAE/ACCA Standard 183, and ISO 52000 — with sub-hourly calculations that account for solar gain across all surfaces, thermal mass and construction materials.
What HVAC systems can be modeled in IESVE?

IESVE offer the most comprehensive coverage across HVAC systems, supporting over 100 pre-configured airside systems including single-zone, multi-zone, and zonal systems, as well as fully customizable plant and waterside loops covering heating, cooling, heat recovery, thermal energy storage, and more.
What compliance standards does IESVE loads software support?

IESVE supports all key ASHRAE Standard 183 requirements through its 3D geometry, physics-based thermal simulation and ASHRAE Heat Balance approach, while reducing the amount of manual rework needed. ASHRAE Standard 183 is now referenced in both ASHRAE 90.1 and IECC as the minimum requirement for load calculations to meet energy codes and regulations.
What reports and outputs does IESVE generate?

IESVE produces a comprehensive range of outputs including heating and cooling load spreadsheets, PDF reports covering system, zone, and room breakdowns, equipment sizing summaries, and as IESVE models the complete system as a network of components with an explicit psychrometric state at each node, its hourly loads reports can drill down into system-level impacts.
How does the HVAC System Design Wizard work?

The wizard automates the full HVAC sizing sequence — from load calculations and equipment sizing through to annual energy simulation and report generation — making it quick and straightforward to configure and optimize HVAC systems. Peak HBM calculated loads can move directly into the System Design Wizard in ApacheHVAC with no manual re-entry as room and zone data flows straight in.
How do I find out more or get started?

Request a free trial or access a live web demo to see the software in action, explore the Mechanical Engineer's Checklist to evaluate how IESVE compares to your current tool, or contact the team directly at sales@iesve.com.

Got a Question?

Contact our team to find out more about load calculations and HVAC design sizing tools in the Virtual Environment.

Capella Building, 7th Floor, 60 York Street, Glasgow, G2 8JX, UK

Tel: +44 (0) 141 945 8500 Email: enquiries@iesve.com