# LoadSizer: HVAC Load & BTU — AC Sizing & Cooling Calculator

> AC Sizing & Cooling Calculator (iPhone/iPad app by Duong Nguyen Huu.)

- Source: https://appshunter.io/ios/app/loadsizer-hvac-load-and-btu/id6817009200 (this page in markdown: same URL + `.md`)
- Developer: [Duong Nguyen Huu](https://appshunter.io/developer/1887479789)
- Category: Productivity, Utilities
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 15.1 · 32 MB
- Languages: American English
- Released: 2026-10-05
- Data updated: 2026-10-08

## What is LoadSizer?

Size the AC right — get a room-by-room cooling and heating load estimate in under a minute, built on the ASHRAE CLTD/SCL method instead of a single "BTU per square foot" guess.

Built for installers doing a quick home survey, engineers who want a fast sanity check before a full Manual J, and homeowners who want more than a rule of thumb before buying an AC.

TWO MODES
- Quick: floor area, ceiling height, room type, main sun-facing side, insulation level, occupants, top floor or not. Instant estimate.
- Detailed: full room construction — exterior walls and windows by orientation (area, U-value, SHGC, shading), roof, ground-floor slab, occupants and activity, lighting, equipment, and outdoor air (ACH).

WHAT YOU GET
- Sensible, latent and total cooling load (W, Btu/h, kW, ton) plus SHR, and a heating load for the coldest design day.
- A horizontal breakdown by component: walls, windows (conduction and solar shown separately), roof, people, lighting, equipment, outdoor air.
- A recommended commercial AC size (5,000-60,000 Btu/h) in Btu/h, ton and HP, rounded up to a size you can actually buy — plus a warning if it's oversized or the load per square foot looks off.

REAL CLIMATE DATA
35 cities across the Americas, Europe, the Middle East and Asia-Pacific, with outdoor design conditions sourced from ASHRAE Climatic Design Conditions — not one flat number for an entire country. Enter your own design climate for anywhere else.

WORKS THE WAY YOU DO
- Fully offline. No account, no tracking, no ads.
- °C/°F, m²/ft², m/ft, and W/Btu-h/kW/ton/HP, each set independently.
- Multiple rooms per project, multiple projects, PDF export.
- English, Spanish, Chinese, Portuguese, Japanese, Korean, Vietnamese and Thai.

Free for unlimited Quick estimates and one Detailed room. LoadSizer Pro (one-time purchase, no subscription) unlocks unlimited rooms/projects and PDF export.

LoadSizer uses a simplified ASHRAE Fundamentals 1997 CLTD/SCL/CLF method for fast sizing guidance — not a substitute for a full Manual J or ASHRAE RTS load calculation, and not certified or endorsed by ASHRAE or ACCA.

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| LoadSizer Pro | $2.99 | one-time |



## Version history (last 1 release)

### 1.0 — 2026-10-05

No release notes.

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## More apps by Duong Nguyen Huu

- [Tích Sản: Giá Vàng & Tài Sản](https://appshunter.io/ios/app/tich-san-gia-vang-and-tai-san/id6761044270)
- [PDFScan Go](https://appshunter.io/ios/app/pdfscan-go/id6761462436)
- [AirCalc Psychrometric](https://appshunter.io/ios/app/aircalc-psychrometric/id6762062746)
- [Drink Water & Pill Reminder](https://appshunter.io/ios/app/drink-water-and-pill-reminder/id6762444133)
- [Meno: Perimenopause Tracker](https://appshunter.io/ios/app/meno-perimenopause-tracker/id6762710155)
- [Barber Việt Nam](https://appshunter.io/ios/app/barber-viet-nam/id6763964976)

All apps by Duong Nguyen Huu: https://appshunter.io/developer/1887479789

## Related topics

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

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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 2026-10-08.*