Comparison

Units vs Unit Converter HVAC

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

Head to head
About

Units

Easily convert between hundreds of units across 43 categories, including currency with daily updated rates. Customize your workflow by hiding or reordering units and categories.

Highlights
  • Hundreds of units across 43 categories
  • Daily updated currency exchange rates
  • Hide unused units
  • Reorder units and categories
  • Universal app support (iPhone, iPod touch, iPad)
Features
Read full description

Units is the fast, friendly unit converter. Type a number into any unit and instantly see it in every other one, all on a single screen. There's no picking what to convert from and to, no digging through menus, and no ads. With more than 800 units across 43 categories, Units covers everyday conversions like length, weight, volume and temperature, and the ones you need less often, from torque and fuel consumption to data rates, shoe sizes and musical notes. SEE EVERYTHING AT ONCE • Enter a value in any unit and every other unit in the category updates as you type • A keypad made for numbers, so the decimal point is always right where you need it CURRENCY • Convert between more than 160 currencies • Exchange rates updated every day MAKE IT YOURS • Hide the units you never use, so the ones you need are always in view • Reorder units and categories so your favorites come first • Switch on a two-column layout to see even more at a glance • Leave a tip to unlock a collection of alternative app icons MADE FOR YOUR DEVICES • Designed for iPhone and iPad, with your categories and conversion side by side on larger screens • Makes full use of iPhone Duo, whether it's open or closed • Handoff picks up a conversion where you left off on another device • Supports Dark Mode and Dynamic Type Units has been converting since 2008, and is lovingly made in Scotland.

About

Unit Converter HVAC

Features
Read full description

HVAC Unit Converter Pro helps HVAC technicians, engineers, refrigeration mechanics, and contractors convert between units instantly. Convert between all common air conditioning and refrigeration units instantly across 8 categories and 40+ unit types - eliminating calculation errors on job sites. 8 CONVERSION CATEGORIES: Temperature - °F, °C, K, °R (Rankine) for climate zones and equipment specs Pressure - PSI, kPa, bar, in. Hg, mm Hg, atm, Pa, in. w.c. (static pressure), microns (vacuum) for gauges and evacuation Energy & Heat - BTU, kJ, kcal, Wh, therm for load calculations Airflow (CFM) - CFM, L/s, m³/h, m³/s, m³/min for ductwork and ventilation Length & Duct - in, ft, mm, cm, m for duct sizing and pipe runs Area Calculations - ft², m², in² for room dimensions and surface area Volume & Capacity - gal, L, ft³, m³ for tank and system volumes Power & Output - BTU/h, W, kW, ton (refrigeration), hp, kcal/h for equipment ratings SMART FEATURES: Instant Conversion - Results update as you type, no button press needed Bidirectional Conversion - One tap to reverse conversion direction instantly Swap Units - Toggle between any unit pair in the same category Works 100% Offline - Field calculations without internet connection Accuracy Verified - Professional-grade precision for system design English & Spanish Support - Bilingual interface for diverse teams WHY HVAC PROFESSIONALS USE THIS APP: Eliminates manual conversion errors that cause mistakes Faster unit calculations than reference tables and charts Cross-checks between imperial and metric systems instantly Prevents equipment sizing errors from unit mistakes Works on every job site without cellular connection Dark theme prevents eye strain during outdoor work CONVERSION EXAMPLES HVAC TECHS USE DAILY: PSI to kPa for pressure readings on gauge conversions BTU to kW for international equipment specifications CFM to m³/s for ductwork design in metric regions °F to °C for climate zone design temperature conversions Tons to kW for heat pump capacity documentation BTU/h to watts for electrical load calculations PERFECT FOR: HVAC technicians on air conditioning service calls HVAC field technicians calculating refrigeration requirements Refrigeration mechanics sizing refrigerant lines AC contractors preparing equipment specifications HVAC design engineers in international projects HVAC apprentices learning unit conversions Building maintenance engineers managing equipment Commercial HVAC system commissioning work A tool trusted by HVAC technician teams nationwide. Part of HVACTools Suite - the complete HVAC technician and refrigeration calculator app collection for field diagnostics and system design. OPTIONAL PRO UPGRADE — $2.99 ONE-TIME IN-APP PURCHASE The following features require a separate one-time in-app purchase. They are not required to use the calculator: • Unlimited saved calculation history • PDF export of results • Dark theme • Ad-free experience

Screenshots

Units4 screens
Unit Converter HVAC4 screens

Verdict

The call

The clearest difference is price: Units at Free against Unit Converter HVAC's $0.99. Unit Converter HVAC's advantage is ads (none vs shown) and iOS requirement (13.0 vs 17.0). On update cadence, 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

CostPrice · In-app purchases · Ads · Monetization

Units is free to download; Unit Converter HVAC costs $0.99 up front. Units sells 3 one-off in-app purchases and Unit Converter HVAC sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

Units ships an update monthly, Unit Converter HVAC every 3 weeks. The most recent releases landed on November 6, 2026 and October 28, 2026 respectively.

Scorecard3 real differences · 7 level
Units versus Unit Converter HVAC: the parameters behind the verdict, then further details
ParameterUnitsUnit Converter HVAC
PriceFree — better$0.99
Rating4.1 (51 ratings) — better—
Positive reviews60.1% of reviews—
Number of ratings51 — better—
Update frequencyMonthlyEvery 3 weeks — better
AdsYesNo — better
In-app purchasesYesYes
MonetizationFree with in-app purchases—
DevicesiPhone, iPadiPhone, iPad, iPod — better
Requires iOS17.013.0 — better
Further details — not scored
Size86 MB34 MB
Age rating4+17+
DeveloperHomegrown Software LtdRizvan Adzhoian

Bugs and requests

Units

Reported bugs

4 issues
  • Crashes when clearing input fields
  • Numerical keypad covers conversion results
  • Incompatibility issues with newer iOS versions
  • Ruler measurements not accurate on all devices

Requested features

5 requests
  • Add nautical units (miles, knots)
  • Improve currency conversion accuracy and updates
  • Allow customization of visible unit categories
  • Add more clothing/shoe size conversions
  • Improve user interface and search functionality

Unit Converter HVAC

Not enough reviews yet to summarise bugs or requests.

In-app purchases

3 purchases

Units

One-time3
  • Small Tip$0.99
  • Medium Tip$2.99
  • Large Tip$4.99
1 purchases

Unit Converter HVAC

One-time1
  • Pro Unlock$2.99

Questions

Is Units free?
Units is free to download, with in-app purchases available.
Is Unit Converter HVAC free?
Unit Converter HVAC costs $0.99, and also offers in-app purchases.
Do Units or Unit Converter HVAC have ads?
Units shows ads; Unit Converter HVAC does not.
Which is updated more often, Units or Unit Converter HVAC?
Units ships an update monthly, and Unit Converter HVAC every 3 weeks. Most recently, Units was updated on November 6, 2026 and Unit Converter HVAC on October 28, 2026.

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