The best HVAC load calculation software in 2026, compared

10 HVAC load calculation tools compared by method, standard, platform, and published price. Commercial (ASHRAE 183) and residential (Manual J) picks.

Disclosure: HVAKR makes one of the tools on this list. We've tried to describe every tool, including ours, from its vendor's own published information, and we say where each one is the better pick.

TL;DR

There is no single best HVAC load calculation program; the right one depends on the building and the standard. For commercial buildings, the established desktop tools are Carrier HAP and Trane TRACE (both ASHRAE Heat Balance) and Elite Chvac (RTS or CLTD), with HVAKR and h2x as browser-based options and IES VE for simulation-heavy work. For residential Manual J, the common picks are Wrightsoft, Elite RHVAC, and Cool Calc, which appear on ACCA's approved software list. Pick on calculation method, how easily a reviewer can audit the inputs, platform, and price.

First, split commercial from residential

Most "best load calc software" lists mix two different jobs:

• Commercial and institutional buildings are calculated with ASHRAE methods from the ASHRAE Handbook of Fundamentals, and ANSI/ASHRAE/ACCA Standard 183 sets the minimum requirements for those calculations in buildings other than low-rise residential.[1] Tools in this group use Heat Balance, Radiant Time Series (RTS), or the older CLTD method.
• Low-rise residential is calculated with ACCA Manual J (loads), Manual S (equipment), and Manual D (ducts). ACCA keeps a list of approved Manual J software, and some building departments ask for it.[2]

A tool built for one is rarely the right tool for the other. Calling a commercial load calculation a "Manual J" is the quickest way to tell a plan reviewer you're in the wrong lane.

How we compared

1. Calculation method and whether the vendor names it. A method you can name is a method a reviewer can check.
2. Standards the vendor says it follows, in the vendor's words.
3. Auditability: can a reviewer see every input and component load without rebuilding the model?
4. Platform and collaboration: Windows desktop, browser, or both; single-user files or shared projects.
5. Published price, as listed on the vendor's site on Oct 28, 2026. "Quote" means no public price.

The comparison

If the table above doesn't display, each of the 10 tools is also described in the "one by one" sections below.

Not on the list yet: Endra (with Planlabs). Endra acquired Swiss startup Planlabs in September 2026 to build its mechanical module. Endra's site lists Mechanical as "ETA 2027," so there are no Endra HVAC load calculations to evaluate today.[3][4] See Planlabs alternative.

Commercial tools, one by one

HVAKR. Browser-based HVAC design for mechanical engineering teams. HVAKR AI proposes spaces from a PDF floor plan and the engineer reviews them; loads use RTS across a design day for each month (288 month-hour points per scope), and ventilation follows the ASHRAE 62.1 Ventilation Rate Procedure.[5] HVAKR publishes how it meets each of the 29 requirements in sections 5 through 10 of Standard 183.[6] Several engineers can edit one live project. Where it's weaker: it isn't a whole-building energy simulation suite, it doesn't do residential Manual J, and firms whose deliverable lives in Revit should know HVAKR starts from PDF or DXF sheets and doesn't need the Revit model. A free HVAKR add-in for Revit 2025 and 2026 round-trips MEP spaces between Revit and HVAKR without re-keying the model, and Team plans and up export gbXML (geometry, constructions, and load inputs, not calculated loads or airflows). On G2, HVAKR is rated 4.7 out of 5 from 27 reviews, as of Oct 16, 2026 (G2).

Carrier HAP. A long-standing standard in commercial design. Carrier describes HAP as combining system design and energy modeling, using the ASHRAE Heat Balance method, calculating 24-hour space and zone loads for a design day in each of 12 months, and sizing by system type, with an hour-by-hour 8,760 energy analysis that reuses the design inputs.[7] If you need ASHRAE 90.1 Energy Cost Budget or Performance Rating Method runs from the same model, HAP is built for that. It's a Windows desktop program (HAP v6.4 lists Windows 11 64-bit; HAP v6.4 release sheet). See HVAKR vs Carrier HAP.

Trane TRACE. TRACE 3D Plus uses the ASHRAE Heat Balance method through a modified EnergyPlus engine, and Trane publishes a Standard 183 compliance statement for it.[8] (Trane) It's a Windows desktop program sold per seat. Trane says TRACE 3D Plus will get one final major release (Version 8) before moving to maintenance and support, that TRACE 700 remains available, and that a CDS TRACE subscription covers TRACE 700, TRACE 3D Plus, and a new cloud-based TRACE platform.[9] If you're on TRACE today, that transition plan is worth reading before your next renewal. See HVAKR vs Trane TRACE.

IES VE. A multi-module simulation suite for Windows. IES lists ASHRAE Heat Balance, CIBSE Admittance, and ANSI/ASHRAE/ACCA Standard 183 loads through its APACHE engine, with ApacheHVAC for system and plant sizing.[10] VE 2026 added an HVAC Design Navigator, a guided workflow from geometry to sized equipment (IES). Strong when the same model has to serve energy, daylight, and CFD work; more than most firms need for peak loads alone. See HVAKR vs IES VE.

Elite Chvac. Commercial loads since 1979, with a switch between RTS and CLTD so you can hand-check CLTD results against Handbook tables. Elite says it complies with ANSI/ASHRAE/ACCA 183-2007, imports and exports gbXML, and sells five versions by room capacity, from $299 for two rooms to $1,499 unlimited.[11] The cheapest credible commercial option on this list if you work alone on Windows.

h2x. A browser-based MEP platform covering HVAC, hydronics, plumbing, and fire protection. h2x says its heat load calculations are "independently verified by CIBSE and aligned with ASHRAE," link straight to duct and pipe sizing, and export to Revit and AutoCAD.[12] A good pick for firms that want one tool across wet and dry trades. See HVAKR vs h2x.

HeatWise. A low-cost browser load calculator with commercial and residential plans and one-month passes.[13] HeatWise says it is built on "ASHRAE methods," runs 288 hourly samples per calculation, and exports PDF and Excel reports; it leaves energy modeling and Revit integration out of scope by design (HeatWise). A fit for firms that want a focused, easy-to-learn load calculator rather than a full design suite.

Residential tools, one by one

Wrightsoft Right-Suite Universal. The broadest residential package: Right-J (Manual J), Right-D, drawing, proposals, radiant, geothermal, and energy links, at $900 per year for the US residential package. Commercial loads come as add-ons, such as Right-CommLoad ($250 per year), which offers ASHRAE RTS or CLTD.[14][15]

Elite RHVAC. Manual J 8th Edition Version 2, Manual D, and Manual S, with a filled-in ACCA Form 310, ACCA design review form, and AHRI equipment data, for $599 one-time on Windows or $239 per year online.[16] See Elite RHVAC alternatives.

Cool Calc. Browser-based Manual J, S, and D with satellite tracing, floor-plan upload, and LiDAR scanning. You can build a project free and pay $45 to see results, or subscribe at $50 per user per month.[17]

All three appear on ACCA's approved software page for full residential load calculation (as Wrightsoft Right-J8, Elite RHVAC, and Cool Calc Manual J), as of Oct 28, 2026.[2]

How to choose

• You stamp commercial mechanical drawings and work in a team: shortlist HVAKR, Carrier HAP, and Trane TRACE. Run the same small building through each and compare component loads, not just the total.
• You need energy compliance runs from the load model: Carrier HAP, TRACE, or IES VE.
• You design plumbing and hydronics too: h2x.
• You work alone on small commercial jobs and want a low one-time cost: Elite Chvac.
• You do residential Manual J for permits: Wrightsoft, Elite RHVAC, or Cool Calc, or another tool on ACCA's list.

What makes a load calc trustworthy

Whatever you pick, a reviewer should be able to answer these from the report without opening your model:

1. Which method (Heat Balance, RTS, CLTD) and which weather data and design percentiles?
2. Which hour and month set the peak, for each space, zone, and system?
3. What are the component loads (walls, glass solar, people, lighting, equipment, ventilation, infiltration), split sensible and latent?
4. Where did each ventilation rate come from (ASHRAE 62.1 table and space type) and what Ez was used?
5. What changed since the last issue?

A tool that makes those answers easy to find is worth more than one that's slightly faster to set up.

FAQ

What is the best HVAC load calculation software?

It depends on the building. For commercial work, Carrier HAP and Trane TRACE are the established desktop choices, Elite Chvac is the low-cost desktop option, and HVAKR and h2x are browser-based. For residential Manual J, Wrightsoft, Elite RHVAC, and Cool Calc are common picks on ACCA's approved list.

Can I use Manual J software for a commercial building?

Generally no. Manual J is ACCA's residential method. Commercial buildings are calculated with ASHRAE methods (Heat Balance or RTS), and ANSI/ASHRAE/ACCA Standard 183 sets minimum requirements for them. ACCA's Manual N covers light commercial. Check what your jurisdiction accepts.

What's the difference between Heat Balance and RTS?

Both come from the ASHRAE Handbook of Fundamentals. Heat Balance solves a heat balance at each surface and the room air every hour; RTS is a simplified method derived from it that converts radiant gains to cooling load with time series. Carrier HAP, TRACE 3D Plus, and IES VE use Heat Balance; HVAKR uses RTS; Elite Chvac offers RTS or CLTD.

Is there free HVAC load calculation software?

Few complete options are free. Cool Calc lets you build a project before paying to see results, HeatWise has a 30-day free trial, HVAKR has 14-day (Solo) and 30-day (Team) trials, and TRACE 3D Plus has a 30-day trial that previews results without printing or exporting them. Check what a trial lets you export.

Which HVAC load calculation software runs in a browser?

HVAKR, h2x, HeatWise, Cool Calc, and Elite RHVAC Online run in a browser. Carrier HAP, Trane TRACE 3D Plus, IES VE, Elite Chvac, and Wrightsoft Right-Suite Universal are Windows desktop programs.

Is Trane TRACE 700 discontinued?

Not as of October 28, 2026. Trane says TRACE 700 remains available during its move to a new cloud-based TRACE platform, TRACE 3D Plus gets one final major release (Version 8), and a CDS TRACE subscription covers all three.

Does HVAKR do Manual J?

No. HVAKR doesn't do residential Manual J. It is built for commercial load calculations under ANSI/ASHRAE/ACCA Standard 183. For residential permits, use a tool on ACCA's approved software list.

Sources (checked Oct 28, 2026 unless noted)

• ACCA approved software: acca.org
• Carrier HAP product page (method, features, price): carrier.com; HAP v6.4 release sheet (Windows 11): shareddocs.com
• Trane TRACE 3D Plus load design calculations (Heat Balance): trace3dplus.help.trane.com; Trane software support lifecycle: trane.com; TRACE 3D Plus FAQ (per-seat licensing): shop.trane.com; Trane Standard 183 compliance article: shop.trane.com; TRACE 3D Plus system requirements and trial: trace3dplus.help.trane.com, shop.trane.com
• IES VE APACHE engine: iesve.com/software/apache; VE 2026 release: iesve.com; system requirements (Windows only): iesve.com
• Elite Chvac: elitesoft.com; Elite RHVAC: elitesoft.com
• h2x heat load calculations: h2xengineering.com; h2x comparison page (browser-based): h2xengineering.com/compare
• HeatWise pricing and homepage: heatwise-hvac.com/pricing, heatwise-hvac.com
• Wrightsoft RSU Residential: wrightsoft.com; Right-CommLoad: wrightsoft.com
• Cool Calc: coolcalc.com
• Endra / Planlabs: endra.ai press release, endra.ai
• HVAKR: cooling loads docs, ASHRAE 183 compliance, pricing
• G2, HVAKR reviews, 4.7/5 from 27 reviews, as of Oct 16, 2026: g2.com/products/hvakr/reviews