6 Best HVAC Load Calculation Software for Contractors, 2027

Key Takeaways

• The category decision comes first: for a residential load, choose a program on ACCA's approved list, then pick the scope and platform that fit your jobs.

• Scope matters more than headline price. Two of the six options are block-load only and cannot replace a room-by-room calculation for duct design.

• Only some vendors publish prices on pages this guide could open. The rest are marked Quote-based or not confirmed instead of estimated.

• License model changes the three-year cost more than the feature list does, because a one-time license and an annual subscription diverge quickly.

• The handoff from a finished load report to a quote is a separate build with its own review points, and it is worth configuring only after export access is confirmed.

• Every price here was read on a vendor page on October 26, 2026. Recheck before you sign anything.

Short answer: an ACCA-listed Manual J program first, then scope

A load calculation estimates how much heating and cooling a house needs, and Manual J is the residential method most contractors and code officials reference. The U.S. Department of Energy says "ACCA's Manual J, Eighth Edition, enables contractors to perform load calculations for homes," and it warns that "Rules of thumb" are "too often used to size comfort systems, which results in excessively oversized systems," according to U.S. Department of Energy (undated page). A 1997 Florida field study points the same way: Over half of 368 Florida homes exceeded 120% of Manual J according to UCF STARS (1997), which means the installed cooling capacity was more than 120% of the calculated load.

For a contractor, the buying decision has two parts. The first is compliance. ACCA says only software it has approved and licensed as "Powered by Manual J" can be considered compliant where codes require Manual J, so the approved list is the starting filter. The second is fit: whether the program covers block, room-by-room, and zone loads, runs on the devices your estimators use, and produces duct and equipment steps in the same license.

Our read is that a shop which designs ducts as well as sizes equipment needs a full residential program with Manual D and Manual S available, while a shop that only needs a whole-house block load on simple jobs can use a cheaper block-only tool. The six options below were chosen because each one appears on ACCA's current list and has a vendor page this guide could open.

How we evaluated these tools

This guide weights six criteria. The ACCA listing and the scope of calculations carry 45 of 100 points, because a calculation that fails a code check costs more than any license fee. The weights are our judgment for a buyer choosing among these options, not a vendor ranking. No product was installed or benchmarked for this guide. Scores come only from ACCA's approved list and from vendor pages opened on October 26, 2026.

Read the table as a checklist. A program that scores well on listing and scope but publishes no price is still a shortlist candidate. It needs a written quote before the cost comparison is complete.

Feature matrix: what ACCA's list confirms

ACCA's approved-software page groups its entries into twelve products: ten full residential load calculation tools and two block-load-only tools, according to ACCA (checked October 26, 2026). ACCA's September 2014 post listed six programs as meeting Manual J requirements, according to ACCA (2014), so the list has grown considerably since then. Because the list changes, confirm each product's current status on ACCA's page before you buy.

The matrix below uses the category and scope lines from ACCA's page. Where a vendor page adds a platform or license detail, we say so. "Not stated" means the page we opened did not say.

ACCA's page does not state an approval edition for each product. Some product names include "J8" or "MJ8," but the page does not explain what those labels mean for approval, so ask the vendor to confirm the edition in writing.

Pricing and three-year cost

Pricing checked October 26, 2026.

Only prices read on a vendor's own page appear in this section. Where a page shows no price, the table says Quote-based. Where a price could not be confirmed during this check, the table says so.

Right-J Mobile subscription: $150 a year according to Wrightsoft (checked October 26, 2026). The vendor describes it as a cloud-based block-load tool, and room-by-room work needs the separately sold Right-Suite Universal software.

Elite's Rhvac Online is a subscription at $239 for one year for buyers without Rhvac 10 for Windows, or $159 for one year for buyers who already own it, according to Elite Software (checked October 26, 2026).

The three-year math is simple arithmetic on the listed price. It assumes the price stays flat, which none of the vendor pages promise. A one-time license has no renewal line, while a subscription repeats every year. Carmelsoft and Adtek publish no price on the pages we opened, so they are Quote-based. Cool Calc's homepage shows a per-user subscription and a per-project option, but this guide could not reach a dedicated pricing page to cite, so no number is printed. CalcuNow's vendor site did not open during this check, so its price is not confirmed.

Vendor profiles

Each profile separates vendor facts from our read. Facts come from the ACCA list or the vendor page named in the profile.

Wrightsoft

Vendor facts. ACCA lists Right-J8 as a full residential program for Windows, and lists Right-J Mobile in the block-load-only category for browsers. The store lists the Right-Suite Universal Residential package at $900 a year, and that package includes Right-J as an active module, according to Wrightsoft (checked October 26, 2026). The Right-J Mobile page says it does not include Google map links or equipment selection. The store also lists a Right-Mobile Consultant with equipment selection and Google Maps links, and its price is in the table above.

Our read. Best fit is a shop that needs ACCA-listed whole-house and room-by-room work on Windows, or a browser-based block load on jobs that need no room detail. The main limitation is that Right-J Mobile cannot do equipment selection or room-by-room design. Also, the product page showed a notification sign-up next to the Add to cart button, so confirm the item can be bought today before you plan around it.

Elite Software

Vendor facts. The Rhvac 10 desktop license is a one-time purchase, and the vendor page lists its modules as J, D, and S. The page says the program calculates both block and room-by-room loads, and it includes a complete ACCA Manual D duct sizing capability and a complete Manual S equipment selection. Rhvac Online is subscription based, and its registration link advertises "One free week active, then demo limited." The desktop license is Rhvac 10 desktop license: $599, one-time according to Elite Software (checked October 26, 2026).

Our read. Best fit is a shop that wants Manual J, D, and S in one purchase and prefers a one-time license. The limitations are that the desktop product runs on Windows, and the cheapest online option, Manual J Calculator Online, covers only Manual J. Choose the online route if you need access without a Windows install, and budget for the annual renewal if you do.

Carmelsoft

Vendor facts. HVAC ResLoad-J is an iPad app. The product page describes both block and room-by-room loads for residential and light commercial buildings, and it says the app performs ACCA Manual J8 calculations. The page lists "Install Now" under "From the App Store" as the only purchase route and shows no price or license model, according to Carmelsoft.

Our read. Best fit is a crew that does field load work on iPads and shares reports with office iPads. Limitations are the iPad-only platform, the lack of a published price, which makes it Quote-based here, and the absence of a stated license model. Ask for the license terms in writing before you assume an annual or per-device cost.

Adtek

Vendor facts. The AccuLoads page describes "block, room x room and zoning calculations" and says it "Includes ACCA Manual S Equipment Selection." It says the programs operate on Windows and can be accessed from Apple or Android devices through Adtek VPC Mobile, according to Adtek. The page shows no price, no license type, and no visible date.

Our read. Best fit is a Windows office that wants block, room, zone, and Manual S selection in one program. Limitations are the missing price and license terms, and the unclear page date. Before you buy, ask for the current version and confirm that the ACCA listing matches it.

Cool Calc

Vendor facts. ACCA lists Cool Calc Manual J as a full residential program for browsers and LiDAR-capable devices. The vendor's homepage pricing menu shows a per-user unlimited subscription and a per-project option, and a higher tier that is not yet available and offers a waitlist. No dedicated pricing page opened during this check, so this guide does not print a figure.

Our read. Best fit is a team that wants browser or LiDAR-capable entry and is comfortable with a per-user subscription. The main limitation here is the price, which we could not confirm from a page to cite. Get the plan name, billing basis, and per-user terms in writing before you compare it with the desktop options.

CalcuNow

Vendor facts. ACCA lists MJ8-Calc under "Manual J Block Load Compliant," limited to block loads, for browsers. The vendor site did not open during this check, so this guide has no vendor-stated price or license model.

Our read. Best fit is a shop that needs only whole-house block loads for jobs that do not require room detail. The limitation is scope: it cannot produce room-by-room or zone results, so it cannot replace a full residential program for duct design. Confirm pricing and current ACCA status before you consider it.

Where the load report hands off to the quote

The calculation is rarely the only slow step. Once a report exists, someone has to copy design loads and equipment choices into a quote, a CRM deal, and a job file. A proposed workflow can take that copy step off the estimator's desk, and US Tech Automations could configure it this way. A trigger fires when a finished report file lands in a designated folder or export queue. The workflow reads the block or room totals and the selected equipment, writes them to the matching HubSpot deal, and sets hubspot_owner_id on the deal so the right estimator owns the record. The output is a draft estimate task that waits for review. Prerequisites are a license that allows a usable export, which the vendor pages checked here do not confirm for PDF, CSV, or XML; HubSpot API access with permission to write deal properties; and one named owner for the field mapping. Human review points are the estimator's check of orientation, infiltration assumptions, and the room list before any figure reaches a customer, and the estimator's sign-off on the equipment size.

The alternative is stitching this together in Zapier, Make, or n8n, or building a script in-house. Those tools can keep run histories, retries, error branches, and audit evidence when they are configured that way. The buyer still has to design and own observability, idempotency so a re-sent file does not create a second deal, escalation when a file fails, access controls on the CRM and the report folder, and maintenance when the export format changes. A proposed US Tech Automations design would differ mainly in what it sets up at the start: a run log for each file, a hold queue for files that fail field mapping, and a named reviewer for each hold. These are configuration choices for a proposed design, not a description of a deployment, and the buyer still owns the credentials and the final review.

Consider a hypothetical shop with two estimators that writes 40 system quotes a year, or 20 per estimator. The owner is choosing between a Right-Suite Universal Residential subscription at $900 a year and a single Rhvac 10 desktop license at $599 once. Over three years the subscription totals $2,700 ($900 times three), while the desktop license totals $599, a gap of $2,101. Routing is the other piece: if each of the 40 deals carries an owner through hubspot_owner_id in HubSpot, each estimator sees 20 records in one queue, and a quote that stalls shows up in one place instead of two inboxes. These inputs are illustrative, not data from a customer, and the same arithmetic works with any listed prices you confirm.

Common mistakes

• Buying a block-only tool for a job that needs room-by-room results for duct design.

• Assuming "ACCA-approved" means any version or any product name, when ACCA's list is the source to check.

• Keeping a rule of thumb as a backup. DOE says rules of thumb lead to excessively oversized systems.

• Comparing a one-time license against an annual subscription without multiplying the subscription over the same period.

• Forgetting the platform. A Windows-only desktop tool does not run on an iPad, and a browser tool may not handle your duct workflow.

• Automating the handoff before confirming export formats and API access, which leaves the workflow with nothing to read.

Glossary

• Manual J: ACCA's residential load calculation method, which estimates the heating and cooling a house needs.

• Manual S: The equipment selection procedure that picks a system based on the calculated load.

• Manual D: The duct design procedure that sizes ducts from the room-by-room load.

• Block load: A whole-house calculation without room-by-room detail.

• Room-by-room load: A calculation for each room, which duct design depends on.

• Powered by Manual J: The ACCA license mark for programs it has approved and licensed.

Who this is for

This guide fits a residential HVAC shop, a home services contractor, or an operations lead who needs a load calculation that holds up at permit review. Choose a full residential Windows program if your jobs include duct design and equipment selection. Choose an iPad or browser tool if your estimators work in the field and the scope is limited to the calculation they need. Choose a one-time license if you want a fixed cost and can keep one Windows machine for the work.

Red flags: a price you cannot confirm on the vendor's own page; a block-only tool for a job that needs room-by-room results; and no confirmed export path into your CRM or job software.

Frequently asked questions

When not to use US Tech Automations. Skip an automated handoff if you run only a handful of load calculations a year, because one license and a manual copy into the quote can cost less than configuring and reviewing a workflow. Skip it if your CRM or job software cannot accept an import or API write, because the workflow has nothing to write to. Skip it if your license exports only a printed report, since someone would still have to re-key the figures. A spreadsheet or the vendor's own report output wins in all three cases.

Is an ACCA-listed Manual J tool required for every job?

Use an ACCA-listed tool wherever your local code requires Manual J, because ACCA's guidance says only programs it has approved and licensed as "Powered by Manual J" count as compliant. Check the local code office before you assume a rule-of-thumb sizing is acceptable for any job.

Which option has the lowest listed price?

Among the listed prices read on vendor pages, the lowest is Elite's Manual J Calculator Online at $149 for one year, which covers Manual J only. The one-time desktop option is $599 with no renewal, so the cheapest choice depends on how many years you keep it.

Can one tool handle block, room-by-room, and duct sizing?

Not every tool does all three. Elite's Rhvac 10 bundle lists Manual J, D, and S together, while Wrightsoft's Right-J Mobile does not include equipment selection and is limited to block loads.

Should a small shop automate the handoff from load report to quote?

Only after the export format and API access are confirmed. Automating before those checks leaves the workflow with nothing reliable to read.

Why are some prices missing from this guide?

Some vendors publish no price on the pages this guide opened, so the table shows Quote-based. Where a page could not be opened or a price was not on a deep page, the table says not confirmed. A guessed figure would not help a buyer.

Does a load calculation decide the equipment size?

The load calculation gives the design load. Equipment selection under Manual S is a separate step, which Elite's Rhvac 10 bundle includes and Right-J Mobile does not.

Conclusion

Start with ACCA's approved list, then choose between full residential scope and a narrower block-load tool based on the work you actually do. For a shop that designs ducts and selects equipment, a full residential program with a clear license model is the safer shortlist. For simple block loads, a browser tool can be enough. Every price here is a snapshot from October 26, 2026, so recheck before you sign. If you want to see how US Tech Automations configures this handoff, see how US Tech Automations configures this.