# iENV vs VPD Chart

The clearest difference is review sentiment: VPD Chart at 74% against iENV's 26%. VPD Chart also leads on rating (4.5 vs 3.1) and ratings volume (30 vs 7). iENV's advantage is in-app purchases (none vs 2) and iOS requirement (12.0 vs 15.1). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. VPD Chart sells 2 in-app purchases, starting at $3.99 per month. iENV asks for nothing beyond the download.

VPD Chart holds the better App Store score, 4.5 against 3.1. Both are backed by a comparable volume of ratings — 7 and 30 respectively. Written reviews point the same way: 26% of iENV's written reviews are positive against 74% of VPD Chart's.

iENV ships an update monthly, VPD Chart every 3 weeks. The most recent releases landed on October 5, 2026 and October 9, 2026 respectively.

## The numbers

| Metric | iENV | VPD Chart |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.1 (7 ratings)](https://appshunter.io/ios/app/ienv/id1260827700/reviews) | **[4.5 (30 ratings)](https://appshunter.io/ios/app/vpd-chart/id6470015847/reviews)** |
| Number of ratings | 7 | **30** |
| Positive reviews | 25.7% of reviews | **73.7% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Monthly | **Every 3 weeks** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 70 MB | 49 MB |
| Requires iOS | **12.0** | 15.1 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [UNI-TREND TECHNOLOGY (CHINA) CO.,LTD.](https://appshunter.io/developer/1207185875) | [INNOVO DEV S.R.L.](https://appshunter.io/developer/1814828527) |

## What reviewers say

### iENV

[App page](https://appshunter.io/ios/app/ienv/id1260827700)

This utility app connects UNI-T environmental meters to your smartphone via Bluetooth. It displays and records real-time data for temperature, humidity, noise, wind speed, light intensity, and rotation speed from compatible UNI-T devices.

**Highlights:** Bluetooth connectivity to UNI-T meters, Real-time data display, Data recording capabilities, Supports multiple environmental parameters, Compatible with various UNI-T meter models

**Features:** macOS Compatibility

**In-app purchases:** none


### VPD Chart

[App page](https://appshunter.io/ios/app/vpd-chart/id6470015847)

This app calculates Vapor Pressure Deficit (VPD) using air temperature, relative humidity, and canopy temperature. It offers real-time charting, sensor integration, and educational tools to understand plant growth environments. Organize data by zones and visualize dew point areas.

**Highlights:** VPD calculation, Interactive VPD chart, Sensor integration, Zone organization, Dew point visualization, Grow Timeline

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| VPD Chart Plus (monthly) | $3.99 | per month |
| VPD Chart Plus (annual) | $29.99 | per year |


## Frequently asked questions

### Is iENV free?

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

### Is VPD Chart free?

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

### Which has better reviews, iENV or VPD Chart?

VPD Chart is rated higher. iENV averages 3.1 out of 5 from 7 ratings, while VPD Chart averages 4.5 from 30 ratings.

### Do iENV or VPD Chart have ads?

Neither iENV nor VPD Chart shows ads.

### Which is updated more often, iENV or VPD Chart?

iENV ships an update monthly, and VPD Chart every 3 weeks. Most recently, iENV was updated on October 5, 2026 and VPD Chart on October 9, 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.*