# SuperCool Slide Rule HVAC — user reviews > 56 indexed App Store user reviews of SuperCool Slide Rule HVAC by Designstein, llc, rated 4.20/5 from 185 ratings. - Source: https://appshunter.io/ios/app/supercool-slide-rule-hvac/id1193020259/reviews - App overview in markdown: https://appshunter.io/ios/app/supercool-slide-rule-hvac/id1193020259.md - Rating breakdown: 5★ 125 · 4★ 22 · 3★ 8 · 2★ 6 · 1★ 24 ## What do users think of SuperCool Slide Rule HVAC? Overall sentiment: mixed **Pros** - 👍 Great HVAC tool - 👍 Informative slide rule - 👍 Helpful for new techs - 👍 Quick and simple - 👍 Easy to use - 👍 All in one app - 👍 Invaluable in the field - 👍 Pocket reference - 👍 Good for duct sizing - 👍 Helps customers understand issues **Cons** - 🐛 Trial period issues - 🐛 App expires frequently - 🐛 Requires re-download - 🐛 Not worth the trouble - 🐛 App messed up - 🐛 Scrambled charts - 🐛 Junk app - 🐛 Paid version still has issues - 🐛 Free not free - 🐛 No cost upfront - 🐛 No way to purchase - 🐛 Closes itself - 🐛 No portrait mode - 🐛 No friction rate selection - 🐛 No quick duct sizing - 🐛 Inaccurate altitude - 🐛 Room calc issues **Commonly reported bugs** - App expires and stops working - Requires constant uninstall/reinstall - App is scrambled and unusable - Superheat and subcooling chart scrambled - Paid version still prompts for payment/trial expired - App continuously closes itself - No setting for altitude - Room calculator gives same results for different room sizes **Most requested features** - Update with R454B - Update with R32 - Add R421a refrigerant - Add R427a refrigerant - Add R744/R290/R1270 refrigerants - Add portrait mode - Allow friction rate selection - Quick duct sizing option - Convert F to C - Convert Psi to Bar - Update for newer iOS - Add ability to buy app ## Newest reviews (10 of 56) ### 3/5 — HVAC *2026-04-02, version 1.0* App does not have r32 or r454b. They need to update ### 4/5 — When yall will add the r32 and r454b refrigerants? *2026-01-31, version 1.0* 👍 ### 3/5 — Good enough *2023-04-17, version 1.0* Having to re download can be quite problematic. Especially if you don’t have service everywhere but when it’s working it’s very helpful ### 4/5 — It’s everything you need *2020-10-01, version 1.0* Down side is you have to redownload the app like once a month ### 1/5 — Free not free! *2019-06-03, version 1.0* I downloaded the app before reading the reviews, and saw where it really wasn’t free at all! I refuse to pay for an app like this! I got way too many on my phone anyway! Deleted it immediately! ### 1/5 — Works great, but... *2019-02-08, version 1.0* Nice app, but it would be nice if they would tell you the cost up front and just get it over with. With apps that perform as Wells’s or better, and free (National Refrigerants is one) why bother? ### 5/5 — Love the app but *2018-12-23, version 1.0* The app is a very good hvac tool but after a few months I try and open it to use it and it shows free trial is up that u have to buy it and trust me I want to buy it I just can’t figure out how yet. U can uninstall it and reinstall it and it will start working again just wish I could buy it. ### 1/5 — Good while it was free! *2018-11-28, version 1.0* I was sold on this app, told all my co workers about it and really enjoyed it. It was nice while it lasted but I will move to something else as will my coworkers since it’s no longer free!!!!! Wish I would have know about the trial mode Sooner, kinda just dropped it on us! Oh well, other apps are available! ### 5/5 — ALL HVAC TECHS NEED THIS APP!!! *2018-10-13, version 1.0* Listen. If you ride around in a van or truck all day long and either diagnose or maintain residential or commercial HVAC systems then you should download this app right now. It’s easy and there is a wealth of information in it. The setting I use the nose is “charge a unit”. Knowing my target superheat without having to go in my van, dig out a dirty slide rule (that’s barley readable), and try to find a rounded number closest to what’s available is no longer needed. I have exact numbers in my face in seconds. The color scheme is easy on the eyes, and honestly this is my “go to” app for any HVAC questions. This app gives you a duct sizing calculator, PT charts, diagnostic follow throughs, and the list goes on and on. DOWNLOAD THIS APP!!! ### 4/5 — PT chart *2018-09-27, version 1.0* There is no setting to change your altitude so if your not at sea level it won’t be accurate. ## Most critical reviews (10 lowest-rated) ### 1/5 — Trial period!? Don’t bother!!! *2026-05-28, version 1.0* The app expires at the worst time and will not work until you delete the app and re download it. This is the third time the app expires when I’m at a site with no internet and no cell service. What am I supposed to do? I’ve complained about this before, I think they use this underhanded tactic to artificially inflate their app download count. PLEASE STOP IT! ZERO STARS!!!! ### 1/5 — Doesn’t work *2025-07-23, version 1.0* Every time you try and open it, says to delete and redownload. Doesn’t have new 454 or 32 refrigerant yet. ### 1/5 — Not worth the trouble *2024-10-04, version 1.0* It would be a good app if it didn’t pull “Trial Period Expired” after each use forcing the deletion and downloading just to get the numbers up. Don’t waste your time. Plenty of other apps have the same functionality ### 1/5 — Why does it even EXPIRE *2024-04-12, version 1.0* The fact that this app you need to uninstall and reinstall ever single time it’s ANNOYING!!! Just so you can have a higher download rate is insane !! ### 1/5 — Trial period!? Don’t bother!!! *2023-03-22, version 1.0* The app expires at the worst time and will not work until you delete the app and re download it. This is the third time the app expires when I’m at a site with no internet and no cell service. What am I supposed to do? I’ve complained about this before, I think they use this underhanded tactic to artificially inflate their app download count. PLEASE STOP IT! ### 1/5 — App messed up *2023-02-22, version 1.0* App is all messed up. Can’t use superheat and subcooling chart. Everything is scrambled together. Haven’t been able to use ### 1/5 — Trial period!? *2022-10-21, version 1.0* The app expires at the worst time and will not work until you delete the app and re download it. This is the third time the app expires when I’m at a site with no internet and no cell service. What am I supposed to do? I’ve complained about this before, I think they use this underhanded tactic to artificially inflate their app download count. PLEASE STOP IT! ### 1/5 — App messed up *2022-09-18, version 1.0* App is all messed up. Can’t use superheat and subcooling chart. Everything is scrambled together. Happened yesterday ### 1/5 — Junk *2022-06-25, version 1.0* All you see is from 3+ years ago. The app constantly puts you in a “free trial” period that you have to constantly delete and reinstall the app. Why bother ! ### 1/5 — Rip off!!!!!!! *2019-12-02, version 1.0* I paid for the full version of this app and it still tells me to uninstall it or pay for full subscription!!! What a joke!!! ## Most praised reviews (10 highest-rated) ### 5/5 — R454B? *2026-06-10, version 1.0* Best app there is but any chance of an update with R454B? ### 5/5 — Amazing app! *2025-06-28, version 1.0* I really hope the developer updates this app with the new refrigerants that are now out. This is an awesome app! ### 5/5 — Everything you in the palm of your hand. *2025-03-18, version 1.0* Tried others but I keep coming back. ### 5/5 — Amazing app *2025-02-26, version 1.0* I hope work ASAP ### 5/5 — Great HVAC Tool *2024-10-28, version 1.0* I absolutely love this app if your a manager have your less experienced guys download this you can help them solve almost any issue. If you have estimators for replacement great tool for duct sizing and checking, also helps customers understand what is wrong with their existing duct systems. ### 5/5 — Very informative slide rule👍 *2023-06-14, version 1.0* I guess you know that you’re app doesn’t work ### 5/5 — Troubleshooting-Compressor Windings *2023-04-21, version 1.0* Please fix the bug, otherwise I love this app ### 5/5 — GREAT APP *2022-03-11, version 1.0* PHENOMENAL APP, I just wish the creator stuck with it, this could be epic. I’ve been using it for years. When you have tons of calls backing up and need to keep trucking, it’s quick simple and helps move onto the next call quickly. ### 5/5 — Good app for field use. *2021-06-16, version 1.0* I consider myself an intermediate residential HVAC technician. I have found this app very helpful in many different situations in the field!! ### 5/5 — Great tool for Comfort Advisors! *2020-06-27, version 1.0* I am a residential comfort advisor, and every home I walk into, I always have my notepad, measuring tape, laser measuring tool, & the SuperCoolSlide! This app + the actual SCSR, it seriously makes duct sizing a piece of 🍰 ! --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-04.*