iENV vs VPD Chart
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
iENV
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.
- Bluetooth connectivity to UNI-T meters
- Real-time data display
- Data recording capabilities
- Supports multiple environmental parameters
- Compatible with various UNI-T meter models
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iENV is an App which connects UNI-T’s mini environmental series meters to a cell phone through Bluetooth. It is a free App which can be downloaded from App Store. iENV is able to display and record real-time temperature/humidity, noise level, wind speed, light intensity and rotate speed through UNI-T meters UT333BT, UT353BT, UT363BT, UT383BT, UT372D , UT325F, UT381A , and UT382A respectively.
VPD Chart
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.
- VPD calculation
- Interactive VPD chart
- Sensor integration
- Zone organization
- Dew point visualization
- Grow Timeline
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The app calculates VPD using air temperature, relative humidity, and canopy temperature. View real-time VPD values on an interactive chart. Connect sensors for automated readings or manually input data via intuitive sliders and text inputs. Key features: • Interactive VPD chart with manual input • Default crop types • Organize charts by assigning them to different zones • Display spots that share the same VPD value • Zoom in and out of the VPD chart with a two-finger pinch and drag to pan around • VPD Target - long-press the chart to set a target VPD value • Dew point area visualization • Grow Timeline • Sync sensor historical data by importing it from sensor's app, via cloud APIs, or bluetooth • Explore sensor history by panning and zooming Supported bluetooth devices: • AC Infinity Cloudcom B2, A2, B1 • SensorPush: HT1, HT.w, HT.xw • Govee: H5051, H5072, H5074, H5075, H5100, H5101, H5102, H5103, H5104, H5105, H5174, H5177, H5179 • SwitchBot: Meter, Plus, Indoor Outdoor • Ruuvi: RuuviTag and RuuviTag Pro • Inkbird: IBS-TH1, IBS-TH1 Plus, IBS-TH2, IBS-TH2 Plus • ThermoPro: TP351, TP357, TP358, TP359 • VIVOSUN AeroLab THB1S • Shelly BLU H&T • Xiaomi Mijia 2 (LYWSD03MMC) (original and pvvx firmware) Supported devices with API connectivity: • Govee • Pulse • UbiBot • Ecowitt • Tuya • SensorPush Educational benefits: • Interactive Learning: Explore the dynamics of VPD based on changes in temperature and relative humidity by manipulating input sliders and animating the chart • Canopy - Air Temperature Link: Easily visualize and set values by linking canopy temperature to air temperature • Chart Bands Control: Toggle chart bands on/off (dew, under transpiration, prop, veg, flower, over transpiration) for a comprehensive understanding Included: 1 chart with manual input and grow timeline, device data sync & explore, default crops VPD Chart Plus subscription unlocks: • Unlimited charts • Automated VPD calculation by using sensors as the input data source • Background monitoring and Alerts (temperature, RH, VPD) • VPD history timeline, available on sensor-driven VPD charts • Custom crops Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Screenshots
Verdict
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.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
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.
| Parameter | iENV | VPD Chart |
|---|---|---|
| Price | Free | Free |
| Rating | 3.1 (7 ratings) | 4.5 (30 ratings) — better |
| Positive reviews | 25.7% of reviews | 73.7% of reviews — better |
| Number of ratings | 7 | 30 — better |
| Update frequency | Monthly | Every 3 weeks — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free — better | Free with in-app purchases |
| Devices | iPhone, iPod | iPhone, iPad, iPod — better |
| Requires iOS | 12.0 — better | 15.1 |
| Further details — not scored | ||
| Size | 70 MB | 49 MB |
| Age rating | 4+ | 4+ |
| Developer | UNI-TREND TECHNOLOGY (CHINA) CO.,LTD. | INNOVO DEV S.R.L. |
Customer experience
iENV
VPD Chart
In-app purchases
iENV
No in-app purchases
VPD Chart
- VPD Chart Plus (monthly)3 Days trial$3.991 Month
- VPD Chart Plus (annual)3 Days trial$29.991 Year








