IN HVAC Calculator vs Flex Controller
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
IN HVAC Calculator
This app provides HVAC inspection tools and guidelines for home inspectors. It helps estimate equipment age, size, and requirements, giving inspectors confidence in their reports.
- Equipment circuit requirements calculator
- AC tonnage estimation by model number
- HVAC manufacture date lookup
- Combustion air requirements guide
- General HVAC reference information
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Inspector Nation presents a general reference application to provide insight into the world of HVAC equipment inspection. It is never good practice to mention the exact age or tonnage rating in the home inspection report, but having a reference point of age and size gives the home inspector confidence to map out the inspection and set the tone for the report. This application will aid the inspector by providing several HVAC-related inspection calculators as well as guidelines for approximate values for (1) equipment circuit requirements, (2) air conditioner tonnage based on the model number, (3) HVAC manufacture date, and (4) combustion air requirements. Contact us if you'd like to request a feature for a future release!
Flex Controller
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This application is used for the setup and configuration of the Aquasol Flex Chemical Controller.
Screenshots
Verdict
The clearest difference is update cadence: IN HVAC Calculator at every 6 months against Flex Controller's every 13 months. IN HVAC Calculator also leads on iOS requirement (12.0 vs 15.0). On price, ads, in-app purchases and device support 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
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
IN HVAC Calculator ships an update every 6 months, Flex Controller every 13 months. The most recent releases landed on September 22, 2026 and October 8, 2026 respectively.
| Parameter | IN HVAC Calculator | Flex Controller |
|---|---|---|
| Price | Free | Free |
| Rating | 4.2 (11 ratings) — better | — |
| Number of ratings | 11 — better | — |
| Update frequency | Every 6 months — better | Every 13 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 12.0 — better | 15.0 |
| Further details — not scored | ||
| Size | 27 MB | 31 MB |
| Age rating | 4+ | 4+ |
| Developer | Gregory Enterprises | Poolsure, a division of Aquasol Controllers, Inc. |
In-app purchases
IN HVAC Calculator
No in-app purchases
Flex Controller
No in-app purchases
Questions
Is IN HVAC Calculator free?
Is Flex Controller free?
Do IN HVAC Calculator or Flex Controller have ads?
Which is updated more often, IN HVAC Calculator or Flex Controller?
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