Comparison

HVAC vs FastXY

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

Head to head
About

HVAC

This app provides quick and easy calculations for HVAC professionals and enthusiasts. It simplifies complex formulas for energy use, airflow, and duct dimensions, making them accessible on your iPhone or iPad.

Highlights
  • SFP calculations
  • Heat recovery efficiency
  • Air velocity in ducts
  • Duct dimensioning
  • Pressure drop calculations
  • Equivalent diameters
Features
Read full description

HVAC Calculator is an app that performs many calculations that are useful to have available for anyone working with or have interest in HVAC and energy use in buildings. The app performs many of the calculations that you never remember the formulas for when you need them for quick calculations, for example in a meeting or out on the construction site. Many of the calculations can also be a bit difficult to calculate with a normal calculator. Now you can perform these calculations easily on your iPhone/iPad. The app is universal, so you only have to buy it once to use it on both iPhone and iPad. The app helps you calculate all this and more: -SFP from measured/design fan power and airflow -SFP at reduced airflow for VAV ventilation -SFP at design conditions or maximum performance for VAV ventilation -Temperature efficiency of heat recovery -Temperature after heat recovery unit (HRU) in air handling unit (AHU) -Temperature of exhaust air from air handling unit after heat recovery -Actual temperature efficiency of heat recovery when the exhaust temperature is limited to minimum 5°C for reuse as frost free garage ventilation -Air velocity in ducts with known dimensions and airflow -Maximum airflow in a duct with dimensions and maximum air velocity as specified requirements -Dimensions of rectangular and circular spiral ducts for specified air flow and velocity requirements -Pressure drop in Pa/m for rectangular and circular spiral ducts -Equivalent diameters for rectangular ducts -Hydraulic diameter for rectangular ducts

About

FastXY

This app enables high-accuracy GNSS data collection for professional surveying and GIS applications. It supports various data types, stake-out functions, and offline use, with multiple export options for seamless integration with other software.

Highlights
  • High-accuracy GNSS data collection
  • Point, line, and polygon data capture
  • Submeter or centimeter (RTK) accuracy
  • Stake-out feature
  • Offline data collection
  • Multiple export formats (CSV, shp, DXF/DWG)
  • Feature/attribute/value pick lists
Features
Read full description

FastXY is a high-accuracy GNSS data collection app designed for use with Eos GNSS receivers (www.eos-gnss.com). Collect point, line, polygon data with submeter or centimeter (RTK) survey-grade accuracy or use its stake-out feature to stake points to survey-grade accuracy. After data is collected, upload your data via CSV, shp, DXF/DWG to your favorite GIS/CAD. Key features: -Setup feature/attribute/value pick lists for easy field data entry. Collect ad hoc data in the field without setting up ahead of time. -Stakeout points loaded from DXF/DWG, CSV or shp files. -Collect raw data for post-processing and auto-submit to OPUS from your mobile device (https://www.ngs.noaa.gov/OPUS/) -World-wide 3D base map for visual reference in the field. -Doesn’t require an internet connection.

Screenshots

HVAC4 screens
FastXY4 screens

Verdict

The call

The clearest difference is price: FastXY at Free against HVAC's $4.99. FastXY also leads on rating (5.0 vs 4.0) and update cadence (every 2 months vs every 5 months). On ads, in-app purchases, device support 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

FastXY is free to download; HVAC costs $4.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

FastXY holds the better App Store score, 5.0 against 4.0. Both are backed by a comparable volume of ratings — 1 and 3 respectively.

UpkeepUpdate frequency

HVAC ships an update every 5 months, FastXY every 2 months. The most recent releases landed on November 1, 2026 and November 3, 2026 respectively.

Scorecard5 real differences · 5 level
HVAC versus FastXY: the parameters behind the verdict, then further details
ParameterHVACFastXY
Price$4.99Free — better
Rating4.0 (1 ratings)5.0 (3 ratings) — better
Positive reviews100.0% of reviews—
Number of ratings13 — better
Update frequencyEvery 5 monthsEvery 2 months — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidFree — better
DevicesiPhone, iPadiPhone, iPad, iPod — better
Requires iOS16.015.5 — better
Further details — not scored
Size14 MB114 MB
Age rating4+4+
DeveloperTrond RossvollDiscovery Management Group

Customer experience

HVAC

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

FastXY

All ratings3 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

HVAC

No in-app purchases

None

FastXY

No in-app purchases

Questions

Is HVAC free?
HVAC costs $4.99, with no in-app purchases.
Is FastXY free?
FastXY is free to download, with no in-app purchases.
Which has better reviews, HVAC or FastXY?
FastXY is rated higher. HVAC averages 4.0 out of 5 from 1 ratings, while FastXY averages 5.0 from 3 ratings.
Do HVAC or FastXY have ads?
Neither HVAC nor FastXY shows ads.
Which is updated more often, HVAC or FastXY?
HVAC ships an update every 5 months, and FastXY every 2 months. Most recently, HVAC was updated on November 1, 2026 and FastXY on November 3, 2026.

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