HVAC Pro Calculator · 2026
Most techs work off a pressure-temperature chart screenshotted from a forum, a supplier PDF or a group thread. It is usually right. The problem is you cannot tell when it is not — there is no refrigerant revision on it, no date, and nobody to ask. HVAC Pro Calculator puts the citation on the same screen as the answer.
Free BTU load + converter No ads No data collected Works offline
The honest comparison
This is not a swipe at any particular chart or manufacturer app — plenty of them are accurate. It is about what you can prove when a number is questioned, and how long it takes to get that number while you are standing on a roof.
| A screenshotted chart | HVAC Pro Calculator | |
|---|---|---|
| Where the number came from | Unknown. No source, no revision, no date on the image. | Cited on the same screen — ASHRAE, NEC or SMACNA. |
| Getting the equipment details in | Read the nameplate, type it into a phone with gloves on. | PlateScan reads the nameplate with the camera. |
| Superheat and subcooling | Cross-reference the chart, do the arithmetic in your head. | Entered readings, worked result, source shown. |
| Voltage drop | A different chart, or a different app. | NEC voltage drop in the same place as the rest. |
| Duct sizing | A wheel, a spreadsheet, or memory. | Manual D duct sizing, SMACNA cited. |
| In a basement with no signal | Fine — it is a saved image. | Fine — everything runs on the device. |
| What it costs | Free. | Free for BTU load and the converter. Pro is $4.99/mo or $19.99/yr. |
A saved chart is free and it works in a dead zone. If that is all you need, keep using it. The case for a cited tool is narrower and more specific: the day a number gets challenged — by an inspector, a customer, or your own second-guessing — you can show where it came from.
What is in it
Heating and cooling sizing from square footage, ceiling height and climate zone.
ASHRAE-derived · FreeDuct sizing for the airflow you actually need, not the one that fits the opening.
SMACNA citedConductor sizing and voltage drop against the code limits, on the same screen.
NEC citedPressure-temperature values with the refrigerant named and the source shown.
Cited on the glassPut your readings in, get the worked result and what it points at.
Shows the workingPoint the camera at the nameplate instead of typing it in. Runs on the phone, works with no signal.
On-device · OfflineWhat it costs
BTU load sizing and the unit converter are free and stay free. There are no ads anywhere in the app, and it does not collect your data.
BTU load sizing and the unit converter. No account, no ads.
Every calculator, PlateScan, and the cited sources. Billed monthly.
The same, billed once a year. Starts with a 3-day free trial.
Questions
Nothing, until the number is questioned. A chart saved off a forum carries no refrigerant revision, no date and no source. It is usually right, and you cannot tell when it is not.
ASHRAE for load work, NEC for voltage drop and electrical limits, SMACNA for duct sizing. The citation sits next to the answer, not buried in a help page.
You point the camera at an equipment nameplate and it reads the plate instead of you typing it into a phone with gloves on. It runs on the device and works without a signal.
Yes. The calculators and PlateScan all run on the phone — crawl spaces, mechanical rooms and basements included.
PLAYRIOT, a small app studio in San Diego. No ads, and the app does not collect your data.