The "HVAC Psychrometric Plus" app is the #1 selling psychrometric application for the Apple iPhone and iPad. Thousands of happy users have downloaded this useful application for performing quick and simple psychrometric analysis. Just a few reasons why you should buy this application:

1. The Psych Plus is now a universal app, meaning that it is optimized for the iPhone and iPad.

2. This app was developed by Carmel Software, a company that has been developing software for 20 years. We are experts in software design and HVAC analysis.

3. It allows you to easily perform single-state and mixed-air HVAC psychrometric calculations.

4. Select and update all input parameters and view the calculated results all in the same screen without switching from one screen to another.

5. Select from 23 different combinations of any 2 input parameters such as "Humidity Ratio / Dewpoint Temperature" and much more.

6. Immediately view updated results as you change the input values using the on-screen slider control. You can specify how much to increase or decrease values as you slide the indicator along the slider mechanism.

7. Send an HTML email and a spreadsheet attachment of all of the single-state and mixed-air inputs and results

8. This app now includes the HVAC Equipment Locator. Click here for details:

This application contains two separate input modes. The 1st input mode is the "Single-State" mode that allows you to specify 2 psychrometric parameters for a single stream of air and view the remaining 6 calculated values. You can quickly toggle through 23 different combinations of the 2 input parameters and instantly view the calculated results, all on the same screen.

The 2nd input mode is the "Mixed-Air" mode that allows you to specify 2 psychrometric parameters for each of two air streams to calculate the mixed air psychrometric conditions. Once again, you can toggle through 23 combinations of the 2 input parameters and view all results in one screen.

The following input and output value-types are displayed:

1. Dry-bulb temperature
2. Humidity ratio
3. Relative Humidity
4. Wet-bulb temperature
5. Partial pressure
6. Enthalpy
7. Specific volume
8. Dewpoint temperature
9. Total airflow or mass flow (for mixed-air calcs, only)

You can specify additional parameters such as the altitude of the air being analyzed, the atmospheric pressure, different types of units such as degrees F or R, and English or Metric units.

The "HVAC Psychrometric Plus" application was designed by Carmel Software Corporation, a leader in HVAC design software since 1995. In fact, Autodesk (the makers of AutoCAD) acquired our analysis software and incorporated it into their leading Autodesk Revit software product. In addition, ASHRAE has hired Carmel Software to develop custom mobile apps to accompany their various standards.

We also offer the following apps for the iPhone/iPad:

1. HVAC Residential Load Calcs
2. HVAC Load Plus
3. HVAC Duct Sizer
4. HVAC Pipe Sizer – Gas Low Pressure
5. HVAC Pipe Sizer - Gas High Pressure
6. HVAC Pipe Sizer – Liquid
7. HVAC Pipe Sizer – Steam
8. Steam Tables
9. HVAC Toolkit
10. Psychrometric LT
11. HVAC Pipe Sizer Plus
12. HVAC Pipe Sizer Gas Plus
13. HVAC Quick Load
14. HVAC ResLoad-J
15. HVAC Equipment Locator
16. HVAC Psych HD

What's New

Version 2.1

1. App is optimized for iOS 9
2. Updated the HVAC Equipment Locator module to fix issues that occur in iOS 9

Ratings and Reviews



Does not work. 72/46 is not -7.6 dew point. How to get refund is the ??

Beats using those cardboard psych calculators


I have one of those cardboard Vaisala psych calculators, kind of like a ductulator but for psych. calcs. Anyway, I've been using it for years and it was ok. Now, that I've downloaded this app, I much prefer this: it's quick, let's me specify a large # of input parameters, and instantly displays the results. Good stuff.

I also like the fact I can calculate for high elevations since I live in Denver.

Great work!!!

Great app but...


I've used this app many times in my hvac class and all the values are correct other than enthalpy. So be sure to compare that value to the actual chart because it is way off. I sent a thing to the developers so hopefully the issue can be resolved. The odd thing is that the value for enthalpy when using the mixed stream is correct.


Carmel Software Corporation
19.3 MB
Requires iOS 7.0 or later. Compatible with iPhone, iPad, and iPod touch.
Age Rating
Rated 4+
© 2015 Carmel Software Corporation. All Rights Reserved.
In-App Purchases
  1. HVAC Equipment Locator $9.99


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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