# HVAC Load Calc: BTU Calculator — Manual J AC & heat pump sizing

> Manual J AC & heat pump sizing (iPhone/iPad app by Vladimir Lukashov.)

- Source: https://appshunter.io/ios/app/hvac-load-calc-btu-calculator/id6789243124 (this page in markdown: same URL + `.md`)
- Developer: [Vladimir Lukashov](https://appshunter.io/developer/6783697231)
- Category: Utilities, Productivity
- Price: Free with in-app purchases
- Rating: 5.00/5 from 1 App Store ratings
- Age rating: 4+
- Requires: iOS 17.0 · 13 MB
- Languages: American English
- Released: 2026-07-15
- Data updated: 2026-10-24

## What is HVAC Load Calc?

Estimate a home's heating and cooling loads with a simplified whole-house block calculation, see where the load comes from, and check the equipment you are quoting against it. Use the results as an initial estimate. If your project requires a certified room-by-room Manual J, you'll need a separate calculation.

New subscribers start with a free trial. After it, HVAC Load Calc requires a subscription for all the features below.

Enter the house details
- Floor area, ceiling height, and stories
- Use the site's ZIP code to find the nearest US weather station. You can also search by town, state name, or state code, or enter your own design temperatures.
- Indoor design temperatures, 70 °F heating and 75 °F cooling unless you change them
- Insulation presets for walls, ceiling, and floor, or your own U-values
- Can't see the insulation? Fill in typical walls, ceiling, windows, and air leakage from the year the house was built.
- Window area on each side, a glazing type or the U-factor and SHGC from the NFRC label, and how much of the east, south, and west glass is shaded
- Air tightness as a preset or a blower door CFM50 result
- Ducts in the attic, crawlspace, basement, or garage, with their insulation and sealing
- Occupants

See the results
- Design heating load (BTU/h)
- Design cooling load, split into sensible and latent loads (BTU/h)
- Equivalent cooling tonnage, with a plausibility check for unusually high or low loads
- The load by component: walls, ceiling, floor, doors, windows, sun, infiltration, people, and ducts

Check before you quote
- Equipment check: enter a unit's cooling capacity, heat pump capacities at 47, 17, and 5 °F, or furnace output. See the share of the load it covers, the ACCA Manual S range, the heat pump balance point, and the backup heat needed at design.
- Fuel use check: enter last year's gas, oil, or propane use and compare the load it implies with the calculation.

Save the job
- Start a new job, save changes to the current job, or save an independent copy
- Pick up an unfinished calculation after closing the app
- See each job's loads and tonnage in the saved list without opening it
- Saved jobs, your company details, and your logo sync through iCloud to your iPhone and iPad signed in to the same Apple Account. There's no separate sign-up.

Share a report
- Page one: the design loads, equivalent tonnage, and your equipment and fuel checks
- Page two: the design conditions and where they came from, the load by component, and every input
- Add the client's name, property address, notes, your company contacts, and your logo
- Review the PDF before sharing it like any other file

On iPad, the form and report sit side by side and update as you work.

How the calculation works
The calculation uses textbook ASHRAE heat transfer: envelope conduction, infiltration, solar and internal gains. ACCA Manual J block loads use the same basis. Duct losses follow the ASHRAE residential load factor method, and a blower door result is converted the way Manual J converts it. Design temperatures come from ASHRAE tables where available and from fifteen years of hourly NOAA records elsewhere.

The estimate assumes a square footprint and 40 ft² of exterior doors. You can't change those assumptions.

Cancel anytime in Settings.

Engineering reference only. This is a whole-house block load, not a substitute for a certified room-by-room Manual J or professional engineering judgment.

Terms: https://manualj.vovaluka.com/terms
Privacy: https://manualj.vovaluka.com/privacy

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| HVAC Load Pro | $39.99 | per year |


## Is HVAC Load Calc safe?

Not enough ratings yet to assess HVAC Load Calc.

## Is HVAC Load Calc legit?

HVAC Load Calc: BTU Calculator appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for HVAC Load Calc is 65 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 5 releases)

### 1.2.2 — 2026-10-15

When you come back to a report, the app may ask you to rate it on the App Store. After that it won't ask again for 120 days. Calculations and your saved jobs are unchanged.

### 1.2.1 — 2026-10-12

Tapping the App Store event "Equipment Check by Manual S" opens the equipment check in the app. The App Store listing also has a new name and a Spanish (Mexico) description. Your calculations and saved jobs are unchanged.

### 1.2.0 — 2026-10-07

See where the load comes from: walls, ceiling, floor, windows, sun, infiltration, people, and ducts.

The PDF has a second page with the design conditions, where they came from, the load by component, and every input.

Equipment check: compare a unit's cooling capacity, heat pump capacities, or furnace output with the load and the ACCA Manual S range. See the heat pump balance point and the backup heat it needs.

Fuel use check: compare the load with last year's gas, oil, or propane use.

New inputs: indoor design temperatures, shaded glass, window U-factor and SHGC from the label, a blower door CFM50, and ducts in the attic, crawlspace, basement, or garage. Can't see the insulation? Fill it in from the year the house was built.

Saved jobs, company details, and your logo now sync through iCloud, and your logo appears on the report.

On iPad, picking a weather station by town takes one tap again.

### 1.1.3 — 2026-09-24

Pick up where you left off. The app now saves a draft of your calculation and restores it when you reopen the app, including changes you haven't saved to a job yet.

Add a client's name, property address, notes, and your company contacts to the PDF. Long notes continue onto additional pages. You can save your company details once and reuse them on new jobs.

Drafts and saved jobs stay on this device. Your saved calculation changes only when you choose Save changes.

### 1.1.2 — 2026-09-20

Use "New job" to start a separate calculation for each customer. "Save changes" updates the current job, while "Save a copy" keeps a separate version. The app asks before you leave unsaved changes.

Find weather stations by city, state code, or full state name. If there are no matches, you can search by ZIP code.

The Report button is easier to find. The app checks each PDF before opening the share sheet and shows an error if it can't create the report.

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## More apps by Vladimir Lukashov

- [Candle & Soap Calculator](https://appshunter.io/ios/app/candle-and-soap-calculator/id6783697229)
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- [Daysworth: Daily Budget](https://appshunter.io/ios/app/daysworth-daily-budget/id6787101947)
- [Duct Calculator: HVAC Sizing](https://appshunter.io/ios/app/duct-calculator-hvac-sizing/id6789039757)

All apps by Vladimir Lukashov: https://appshunter.io/developer/6783697231

## Related topics

[manual j](https://appshunter.io/ios/topics/manual-j) · [hvac load calculator](https://appshunter.io/ios/topics/hvac-load-calculator) · [hvac load calculator manual j](https://appshunter.io/ios/topics/hvac-load-calculator-manual-j) · [heat load calculator](https://appshunter.io/ios/topics/heat-load-calculator) · [hvac manual j](https://appshunter.io/ios/topics/hvac-manual-j)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-24.*