Comparison

iCircuit vs HVAC Psych HD

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

iCircuit

Design and simulate analog and digital electronic circuits in real-time. This app offers a comprehensive component library, built-in test equipment, and the ability to create custom elements. It's ideal for learning, prototyping, and validating designs without physical components.

Highlights
  • Real-time circuit simulation
  • Extensive component library (300+)
  • Built-in test equipment (multimeter, oscilloscope)
  • Programmable Arduino and PIC microcontroller support
  • Custom element creation and sharing
  • Audio simulation
Features
Currently charting
Read full description

iCircuit is the premier iPhone and iPad app for designing, simulating, and learning analog and digital electronics. Its advanced simulation engine provides real-time, always-on analysis so your circuits stay powered and live, just like working with real components. Use it like a CAD tool: add components, wire them up, and set their properties. But iCircuit is unlike typical CAD apps because it is always simulating. You do not stop to take a measurement or spend time configuring reports. Instead, you just play with the circuit as you normally would, with the power on. Build circuits with over 300 components, from simple resistors and LEDs to programmable Arduinos (Uno, Nano, Mega, ESP8266, ESP32), Raspberry Pi Pico boards running real MicroPython and CircuitPython, PIC microcontrollers, and 60 4000/7400-series digital ICs (more available with Pro). Connect elements, adjust values, and instantly see the results. BUILT-IN TEST EQUIPMENT • Multimeter: Probe any point to read voltage, current, and power • Oscilloscope: Track multiple signals with touch-controlled time scale, stacked/unstacked views, FFT analysis, and Bode plots • Gauges: Visualize voltages, currents, and frequencies directly in your circuit • Signal generators and configurable sources EXTENSIVE COMPONENT LIBRARY • Raspberry Pi Pico and Pico 2 running genuine MicroPython and CircuitPython firmware • Programmable Arduinos (Uno, Nano, Mega, ESP8266, ESP32) • Programmable PIC microcontrollers (assembly and HEX files, more available with Pro) • Power: Voltage regulators (78xx, LM317), sources, dependent sources, power jacks, and simulated antennas • Analog: Resistors, capacitors, inductors, diodes, BJTs, MOSFETs, thermistors, triodes, and tetrodes • Digital: Logic gates (AND, OR, NAND, NOR, XOR), JK and D flip-flops, and 60 4000/7400-series ICs (180+ available with Pro) • ADCs and DACs • Sensors and displays: LEDs, 7-segment, NeoPixels, matrix displays, thermistors • Electromechanical: Motors, servos, SPST/SPDT and DPST/DPDT switches, push buttons, relays, and speakers SPICE, VERILOG, AND VHDL Import vendor SPICE models and subcircuits and use them as components. Write Verilog or VHDL in the HDL element and wire it to the rest of your circuit. CREATE CUSTOM ELEMENTS Build sub-circuits and custom elements to componentize your designs and create reusable modules. Share your custom elements with others via the iCircuit Gallery. AUDIO SIMULATION Hear your circuits. Speakers, buzzers, and microphones produce real audio output. Perfect for students learning electronics, hobbyists prototyping projects, and engineers validating designs, all without burning out a single component. ABOUT ICIRCUIT PRO (OPTIONAL) iCircuit is a complete app with a one-time purchase. iCircuit Pro is optional and adds extra components (including more PICs and a larger 4000/7400 IC library) and helps fund ongoing development. Pro is not required for core simulation or everyday circuit design. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

About

HVAC Psych HD

An interactive psychrometric chart application for iPad, allowing users to plot and customize HVAC processes. Save, email, and manage unlimited projects with both IP and SI units.

Highlights
  • Interactive psychrometric chart
  • IP and SI unit support
  • Customizable chart appearance
  • Finger-based plotting and editing
  • Save and email charts/data
  • Unlimited project creation
  • Zoom and pinch functionality
Features
Read full description

The HVAC Psychrometric Chart app is the first truly interactive graphical psychrometric chart for the iPad, and it includes both IP and SI units. This app is now optimized for iOS 18.x. Using your finger, you can easily plot HVAC and other psychrometric processes on the iPad screen while you are out in the field, save the graphs, and then email the graph and results to yourself or clients. The HVAC Psych Chart app includes the following features and functionality: 1. Displays a fully customizable psychrometric chart in both landscape and portrait modes. 2. Allows you to customize the graph in many different ways including specifying the psychrometric chart line colors, chart background color, hide/display status of chart lines, point colors, process line colors, units of graph values, and the min/max limits of the chart. 3. Using your finger, you can plot as many points as you want on the screen. As you move your finger around the graph, the psychrometric properties at the top of the screen dynamically update . In addition, you can double-tap a point to display the point properties and then edit them. 4. Create psychrometric processes by plotting points then connecting them with process lines. Also, create custom labels anywhere on the chart. 5. After you have completed creating the chart, you can email a list of all the points and their properties along with a PDF of the chart, itself. 6. Create an unlimited number of psychrometric chart projects. Also, you can create templates that you can reuse over and over again. 7. Zoom in or out of the chart by "pinching" the iPad screen so as to view items in more detail. 8. Display sensible heat ratio (SHR) line 9. Display psych process line as curved along 100% RH line.

Screenshots

iCircuit4 screens

Verdict

The call

The clearest difference is review sentiment: iCircuit at 61% against HVAC Psych HD's 0%. iCircuit also leads on price ($12.99 vs $29.99) and update cadence (every 4 weeks vs every 9 months). HVAC Psych HD's advantage is in-app purchases (none vs 2). On ads, monetization model 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

CostPrice · In-app purchases · Ads · Monetization

iCircuit costs $12.99 and HVAC Psych HD $29.99 up front. iCircuit sells 2 in-app purchases, starting at $1.99 per month. HVAC Psych HD asks for nothing beyond the download.

UpkeepUpdate frequency

iCircuit ships an update every 4 weeks, HVAC Psych HD every 9 months. The most recent releases landed on November 6, 2026 and November 1, 2026 respectively.

Scorecard6 real differences · 5 level
iCircuit versus HVAC Psych HD: the parameters behind the verdict, then further details
ParameteriCircuitHVAC Psych HD
Price$12.99 — better$29.99
Rating3.9 (151 ratings) — better—
Positive reviews61.1% of reviews — better0.0% of reviews
Number of ratings151 — better—
Update frequencyEvery 4 weeks — betterEvery 9 months
AdsNoNo
In-app purchasesYesNo — better
MonetizationPaidPaid
Best chart rank#156 — better—
DevicesiPhone, iPad, iPod — betteriPad
Requires iOS13.013.0
Further details — not scored
Size179 MB2 MB
Age rating4+4+
DeveloperKrueger Systems, Inc.Carmel Software Corporation

Customer experience

iCircuit

All ratings135 ratings
Positive68.1%
Neutral4.4%
Negative27.4%
Written reviews682 reviews
Positive61.1%
Neutral12.6%
Negative26.2%

HVAC Psych HD

Written reviews2 reviews
Positive0.0%
Neutral0.0%
Negative100.0%

Bugs and requests

iCircuit

Reported bugs

4 issues
  • Oscilloscope and meter functions not working properly
  • Saving and loading circuits can be unreliable
  • Inconsistent behavior when rotating/flipping components
  • Crashes when working with larger or more complex circuits

Requested features

5 requests
  • More components (e.g. transformers, triodes, MOSFETs)
  • Ability to create custom components
  • Frequency domain analysis (Bode plots, FFT)
  • Improved wiring and component placement controls
  • Better support for AC circuits and motors

HVAC Psych HD

Not enough reviews yet to summarise bugs or requests.

In-app purchases

2 purchases

iCircuit

Subscriptions2
  • iCircuit Pro (Monthly)$1.991 Month
  • iCircuit Pro (Yearly)$14.991 Year
None

HVAC Psych HD

No in-app purchases

Questions

Is iCircuit free?
iCircuit costs $12.99, and also offers in-app purchases.
Is HVAC Psych HD free?
HVAC Psych HD costs $29.99, with no in-app purchases.
Do iCircuit or HVAC Psych HD have ads?
Neither iCircuit nor HVAC Psych HD shows ads.
Which is updated more often, iCircuit or HVAC Psych HD?
iCircuit ships an update every 4 weeks, and HVAC Psych HD every 9 months. Most recently, iCircuit was updated on November 6, 2026 and HVAC Psych HD on November 1, 2026.

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