Comparison

HVAC RefCharge vs ASHRAE Psychrometric Chart

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

Head to head
About

HVAC RefCharge

This app helps HVAC technicians quickly calculate refrigerant superheat and subcool levels. It supports over 100 refrigerants and offers interactive adjustments for precise charging decisions. Features include atmospheric pressure adjustments and unit customization.

Highlights
  • Superheat and subcool calculations
  • Supports 100+ refrigerants
  • Interactive slider for adjustments
  • Atmospheric pressure compensation
  • Customizable input types
  • Project photo assignment
  • Email report generation
  • English/Metric unit display
Features
Read full description

The HVAC RefCharge app is a refrigerant charging calculator that allows HVAC technicians to perform superheat and subcool refrigerant charge calculations on-the-fly. This app includes pressure/temperature data for over 100 refrigerants. This is a universal app that works on both the iPhone and iPad. This app now includes the HVAC Equipment Locator. Click here for details: http://bit.ly/1yTq539 The following is a list of additional features: 1. Perform superheat refrigerant charge calculations for 100+ different refrigerants. Input the indoor wet-bulb and outdoor dry-bulb temps. to get the target superheat temperature. Then, specify the suction line temperature and pressure to get the actual superheat temperature. The difference tells you whether to charge or not. Also, the app auto-assigns the dew version of azeotropic refrigerant to superheat, if applicable. 2. Perform subcool refrigerant charge calculations for 100+ different refrigerants. Input the indoor wet-bulb and outdoor dry-bulb temps. to get the target subcool temperature. Then, specify the liquid line temperature and pressure to get the actual subcool temperature. The difference tells you whether to charge or not. Also, the app auto-assigns the bubble version of azeotropic refrigerant to subcool, if applicable. 3. Use an interactive slider control to increase or decrease all values and immediately observe calculated results. Also, the slider control allows for "incremental" changes so you can ever-so-slightly change values to observe newly calculated results. 4. Specify atmospheric pressure (other than standard 14.7 psi) so that calculated pressures are adjusted for high elevations like those in Denver and elsewhere. 5. Customize input types so that you can specify manufacturer-specified target superheat/subcool or input indoor dry-bulb/indoor relative humidity in place of indoor wet-bulb temperature. 6. Take a photo and assign it to the project 7. Send an email that includes all inputs, results, and the photo with a custom message 8. Display input and result values in either English or Metric units

About

ASHRAE Psychrometric Chart

This interactive tool allows users to plot and customize psychrometric charts on their iPad. Easily create and save HVAC process graphs, update properties dynamically, and share charts and data via email. Supports both IP and SI units.

Highlights
  • Interactive psychrometric chart plotting
  • Customizable chart appearance
  • Dynamic property updates
  • Create and edit points and labels
  • Email charts and data
  • Unlimited projects and templates
  • 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. It is now optimized for iOS 16. 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

HVAC RefCharge4 screens

Verdict

The call

The clearest difference is price: HVAC RefCharge at $9.99 against ASHRAE Psychrometric Chart's $19.99. ASHRAE Psychrometric Chart's advantage is in-app purchases (none vs 1) and iOS requirement (13.0 vs 17.0). On review sentiment, update cadence, ads and monetization model there is nothing between them.

Scored on Price ยท Rating ยท Positive reviews ยท Number of ratings ยท Update frequency ยท Ads ยท In-app purchases ยท Monetization ยท Best chart rank ยท Devices ยท Requires iOS

CostPrice ยท In-app purchases ยท Ads ยท Monetization

HVAC RefCharge costs $9.99 and ASHRAE Psychrometric Chart $19.99 up front. HVAC RefCharge sells 1 one-off in-app purchase. ASHRAE Psychrometric Chart asks for nothing beyond the download.

UpkeepUpdate frequency

Both ship on a similar rhythm, roughly every 11 months. The most recent releases landed on October 27, 2026 and October 12, 2026 respectively.

Scorecard3 real differences ยท 5 level
HVAC RefCharge versus ASHRAE Psychrometric Chart: the parameters behind the verdict, then further details
ParameterHVAC RefChargeASHRAE Psychrometric Chart
Price$9.99 โ€” better$19.99
Positive reviews33.3% of reviews โ€” better27.3% of reviews
Update frequencyEvery 11 monthsEvery 11 months
AdsNoNo
In-app purchasesYesNo โ€” better
MonetizationPaidPaid
DevicesiPhone, iPad โ€” betteriPad
Requires iOS17.013.0 โ€” better
Further details โ€” not scored
Size6 MB2 MB
Age rating+44+
DeveloperCarmel Software CorporationASHRAE, Inc.

Customer experience

HVAC RefCharge

Written reviews3 reviews
Positive33.3%
Neutral33.3%
Negative33.3%

ASHRAE Psychrometric Chart

Written reviews11 reviews
Positive27.3%
Neutral27.3%
Negative45.5%

In-app purchases

1 purchases

HVAC RefCharge

One-time1
  • HVAC Equipment Locator$9.99
None

ASHRAE Psychrometric Chart

No in-app purchases

Questions

Is HVAC RefCharge free?
HVAC RefCharge costs $9.99, and also offers in-app purchases.
Is ASHRAE Psychrometric Chart free?
ASHRAE Psychrometric Chart costs $19.99, with no in-app purchases.
Do HVAC RefCharge or ASHRAE Psychrometric Chart have ads?
Neither HVAC RefCharge nor ASHRAE Psychrometric Chart shows ads.
Which is updated more often, HVAC RefCharge or ASHRAE Psychrometric Chart?
HVAC RefCharge ships an update every 11 months, and ASHRAE Psychrometric Chart every 11 months. Most recently, HVAC RefCharge was updated on October 27, 2026 and ASHRAE Psychrometric Chart on October 12, 2026.

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