# Switch Always On vs Duct Sizer Calc HVAC

The clearest difference is price: Switch Always On at Free against Duct Sizer Calc HVAC's $0.99. Switch Always On also leads on in-app purchases (none vs 1). Duct Sizer Calc HVAC's advantage is update cadence (every 3 weeks vs every 3 months) and chart position (#184 vs unranked). On ads and device support there is nothing between them.

Switch Always On is free to download; Duct Sizer Calc HVAC costs $0.99 up front. Duct Sizer Calc HVAC sells 1 one-off in-app purchase. Switch Always On asks for nothing beyond the download.

Switch Always On ships an update every 3 months, Duct Sizer Calc HVAC every 3 weeks. The most recent releases landed on November 3, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | Switch Always On | Duct Sizer Calc HVAC |
| --- | --- | --- |
| Price | **Free** | $0.99 |
| Rating | **[5.0 (3 ratings)](https://appshunter.io/ios/app/switch-always-on/id1505114113/reviews)** | — |
| Number of ratings | **3** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 3 weeks** |
| Monetization | Free | — |
| Best chart rank | — | **#184** |
| Size | 50 MB | 34 MB |
| Requires iOS | 15.6 | **13.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 17+ |
| Developer | [Smart Charging Technologies](https://appshunter.io/developer/1505114112) | [Rizvan Adzhoian](https://appshunter.io/developer/1891746079) |

## What reviewers say

### Switch Always On

[App page](https://appshunter.io/ios/app/switch-always-on/id1505114113)

This app remotely monitors and configures smart IoT DC Micro Power Supply devices. It helps improve power reliability for networking equipment and automatically reboots modems and routers when they hang.

**Highlights:** Remote monitoring of power supply devices, Real-time configuration of devices, Automatic reboot of modems and routers, Improve power reliability for networking, Supports multiple devices

**In-app purchases:** none


### Duct Sizer Calc HVAC

[App page](https://appshunter.io/ios/app/duct-sizer-calc-hvac/id6764646921)

**Currently charting:** #184 Top Paid · Utilities (US App Store)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro Unlock | $2.99 | one-time |


## Frequently asked questions

### Is Switch Always On free?

Switch Always On is free to download, with no in-app purchases.

### Is Duct Sizer Calc HVAC free?

Duct Sizer Calc HVAC costs $0.99, and also offers in-app purchases.

### Do Switch Always On or Duct Sizer Calc HVAC have ads?

Neither Switch Always On nor Duct Sizer Calc HVAC shows ads.

### Which is updated more often, Switch Always On or Duct Sizer Calc HVAC?

Switch Always On ships an update every 3 months, and Duct Sizer Calc HVAC every 3 weeks. Most recently, Switch Always On was updated on November 3, 2026 and Duct Sizer Calc HVAC on October 28, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*