# Isoterm vs PetFolder

The clearest difference is in-app purchases: Isoterm at none against PetFolder's 2. Isoterm also leads on iOS requirement (13.4 vs 17.0). PetFolder's advantage is ads (none vs shown) and update cadence (every 3 days vs every 4 months). On price and device support there is nothing between them.

Both are free to download. PetFolder sells 2 in-app purchases, starting at $2.99 per month. Isoterm asks for nothing beyond the download.

Isoterm ships an update every 4 months, PetFolder every 3 days. The most recent releases landed on October 13, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | Isoterm | PetFolder |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | Yes | **No** |
| Update frequency | Every 4 months | **Every 3 days** |
| Monetization | Ad-supported | — |
| Size | 18 MB | 61 MB |
| Requires iOS | **13.4** | 17.0 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [ROMAD SEL COM SRL](https://appshunter.io/developer/1741715251) | [BARACONDA S.R.L.](https://appshunter.io/developer/1856368385) |

## What reviewers say

### Isoterm

[App page](https://appshunter.io/ios/app/isoterm-calculator-energetic/id6498631420)

Evaluate your home's energy efficiency and get a detailed report on its energy class. Discover the best thermal insulation solutions for your building and stay updated on national green home programs through articles and push notifications.

**Highlights:** Energy efficiency evaluation, Detailed energy class report, Thermal insulation solutions, National program updates, Push notifications for news

**Features:** macOS Compatibility

**In-app purchases:** none


### PetFolder

[App page](https://appshunter.io/ios/app/petfolder/id6757006256)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium Subscription | $2.99 | per month |
| Premium Monthly | $29.99 | per year |


## Frequently asked questions

### Is Isoterm free?

Isoterm is free to download, with no in-app purchases.

### Is PetFolder free?

PetFolder is free to download, with in-app purchases available.

### Do Isoterm or PetFolder have ads?

Isoterm shows ads; PetFolder does not.

### Which is updated more often, Isoterm or PetFolder?

Isoterm ships an update every 4 months, and PetFolder every 3 days. Most recently, Isoterm was updated on October 13, 2026 and PetFolder on October 24, 2026.

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