Psychrometrics vs Control System Calc
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Psychrometrics
This app provides tools for analyzing and quantifying air and moisture properties. It offers a comprehensive calculator, interactive chart, and project management features for HVAC engineers, meteorologists, and industrial professionals. Supports both SI and IP units for versatile use.
- Comprehensive psychrometric calculator
- Dual units support (SI/IP)
- Psychrometric process simulation
- Interactive psychrometric chart
- HVAC project management
- Printable project reports
- User-friendly interface
Read full descriptionHide full description
Psychrometric calculations and interactive Charts. Calculate air properties, plot points and processes on the psychrometric chart, build complete systems, and export project reports to PDF. Whether you're analyzing a single air state or organizing a full HVAC workflow, Psychrometrics gives you the tools to work faster and more clearly on iPhone, iPad and macOS. Key Features Psychrometric Calculator Calculate dry-bulb temperature, wet-bulb temperature, relative humidity, humidity ratio, dew point, enthalpy, and other key air properties. Interactive Psychrometric Chart View psychrometric points and processes directly on the chart. Tap anywhere to instantly read the air properties at that point. Psychrometric Processes Model common HVAC processes including Cooling Coil, Adiabatic Mixing, Sensible Heating, Heating & Humidification, and Evaporative Cooling. Psychrometric Systems Create points, connect processes, and organize complete psychrometric systems for your projects. SI and IP Units Switch between metric and imperial units to match your workflow and project requirements. Project Saving and Management Save, load, and manage multiple psychrometric systems whenever needed. PDF Export and File Sharing Export project tables and charts to PDF, and share project files across iPhone and iPad. Built for iPhone, iPad, and macOS A clean interface designed for fast, practical psychrometric work. Light and Dark Mode Choose between light and dark appearance to match your preferences. Feedback is always welcome and helps shape future updates.
Control System Calc
Read full descriptionHide full description
Control System Calc (ControlCalc) is an engineering tool for control engineers, R&D staff and students. Enter a transfer function to perform PID tuning, frequency-domain analysis and time-domain simulation — turning textbook control theory into a pocket tool you can use anywhere. All calculations run locally on your device, no internet required. KEY FEATURES ■ PID Tuning Five classic tuning methods built in: Ziegler-Nichols open-loop step, Cohen-Coon, Ziegler-Nichols closed-loop ultimate, plus IMC-Lambda and AMIGO. Each method includes guidance on when to use it. ■ Closed-Loop Step Simulation Simulate the closed-loop step response with an FOPDT model and a PID controller with derivative filtering. View the control effort u(t) to spot actuator saturation, and fine-tune parameters by hand. ■ Bode Plot & Stability Margins Draw magnitude and phase curves on a log scale, with automatic 0 dB / −180° reference lines, gain margin, phase margin and crossover frequencies — stability at a glance. ■ Step Response & Performance Metrics RK4 time-domain simulation that automatically computes overshoot, rise time and settling time. ■ Second-Order Designer Back-solve system parameters from overshoot Mp / settling time ts, or from damping ratio ζ / natural frequency ωn, then push them to the step-response page in one tap. ■ Root Locus & Nyquist (Pro) Root-locus branch tracing with the imaginary-axis stability boundary, an equal-aspect Nyquist plot with unit circle, plus pole/stability analysis for deeper insight. THOUGHTFUL DETAILS • Built-in library of classic example models — tap to load and go • Draggable readouts on time-domain curves (live t / y display) • Numeric keyboard with a Done button; input parameters persist automatically • Simplified Chinese / English / German / Japanese, switchable in-app instantly PRO UPGRADE (one-time purchase) • Removes all ads • Unlocks IMC-Lambda / AMIGO tuning methods • Unlocks Nyquist plot, root locus and pole/stability analysis • Unlocks CSV data export Buy once, keep forever. Family Sharing supported. WHO IS IT FOR Control, electrical, mechatronics and process engineers, R&D and commissioning staff, students taking control-theory courses, and anyone who needs to quickly validate a control-system design. DISCLAIMER All results are provided for engineering reference only. Real-world system design and commissioning should combine field conditions with professional judgment. Have feedback or questions? Contact us from the Settings page.
Screenshots
Verdict
The clearest difference is price: Control System Calc at Free against Psychrometrics's $3.99. Psychrometrics's advantage is ads (none vs shown). On update cadence, in-app purchases, device support and iOS requirement 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
Control System Calc is free to download; Psychrometrics costs $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Psychrometrics ships an update every 3 months, Control System Calc every 2 months. Both last shipped on October 20, 2026.
| Parameter | Psychrometrics | Control System Calc |
|---|---|---|
| Price | $3.99 | Free — better |
| Rating | 4.2 (12 ratings) — better | — |
| Positive reviews | 20.0% of reviews | — |
| Number of ratings | 12 — better | — |
| Update frequency | Every 3 months | Every 2 months — better |
| Ads | No — better | Yes |
| In-app purchases | No | No |
| Monetization | Paid | — |
| Devices | iPhone, iPad | iPhone, iPad |
| Requires iOS | 18.6 | 17.0 — better |
| Further details — not scored | ||
| Size | 2 MB | 9 MB |
| Age rating | 4+ | 4+ |
| Developer | Wassim Murr | 洋 刘 |
In-app purchases
Psychrometrics
No in-app purchases
Control System Calc
No in-app purchases
Questions
Is Psychrometrics free?
Is Control System Calc free?
Do Psychrometrics or Control System Calc have ads?
Which is updated more often, Psychrometrics or Control System Calc?
Other comparisons















