The field book, rebuilt as a decision engine.
The numbers used to live in a book and your work lived on a notepad. Intry puts both on your phone at no cost, reads a number back as a verdict where the reading calls for one, stacks the readings into one job, and hands the job to your AI agent. No login, no ads, no app store.
On a computer? Open intrysys.com on your phone to add it.
The book had the numbers.
For decades the numbers lived in a book. Ugly's in your back pocket. The code book on the seat. A pressure-temperature chart taped inside the van. They worked. You still had to find the table, read it in bad light, and do the math by hand.
The notepad had your work.
The other half never made it into any book. The bends you marked. The superheat you read. The panel you sized. That lived on a notepad, a scrap of drywall, or your memory. It was gone by the next callback.
Gone by the next callbackIt knows where its answer stops.
A calculator gives you a number for whatever you type in. A chatbot on its own answers from memory. An Intry engine first checks whether the reading can support an answer. When it cannot, it says so and names what is missing; when the answer holds only under a condition, it names the condition. These three are what the engines returned on one example job, the Miller Rd condenser, as your agent gets them.
A tool that knows when to stop is a tool you can sign under.
- Charge: Superheat & Subcooling CalculatorSuperheat in band, charge not assessed (needs confirmation)
Which reading sets the charge depends on the equipment, and that has not been stated.
- Circuit: MCA & MOCP Breaker CalculatorCheck on site
The 40 A breaker is above the 20 A that NEC 240.4(D) would otherwise allow on a #12 CU conductor, and on this circuit that is correct.
- Room limit: A2L Refrigerant Charge Limit CalculatorCheck on site
This answer assumes the space does NOT sit above another level that it connects to through a permanent opening reaching the floor with no door, such as an open stair or a wide cased opening.
A calculator, a chatbot, and Intry.
| What you need on the job | Intry | A plain calculator | A chatbot on its own |
|---|---|---|---|
| Gives you the number | Yes, from a locked engine | Yes, for whatever you type | Yes, from memory |
| Says what it means | A verdict, where the reading calls for one | No | Its own read |
| Shows where it came from | The code section, the manufacturer document or the rule | No | Not the table it used |
| Stops when it cannot tell | Refuses, and names the missing reading | No, it computes anyway | No built-in rule for when to stop |
| Keeps the job | Readings stack into one job on your phone | No | Inside one chat |
| Works with no signal | Yes, for the tools it keeps on your phone and any you have opened | Yes | No |
| Hands the job to your AI agent | Yes, and your agent can call its engines | No | It is the agent, without the engines |
The library behind it.
A calculator computes from a primary document where one sets the number: the code book, the manufacturer's own installation manual or chart, the federal rule as published, not a page that copied them. Where a figure is a field rule of thumb or the tool's own band, the result says so. The count takes in the code books and standards the engines compute from, the NEC among them, plus the manufacturer manuals and charts, the federal, state and city documents and the equipment databases on the records they ship with.
The automated checks re-derive the calculators' numbers from locked source modules on every build. It is our own gate, and it does not make any single answer infallible, so each result names its source for you to check.
Where each call pays.
The same 39 calls the homepage walks through stage by stage, sorted here by what they are worth to you. Intry answers them; your agent carries the job to the supply house, the customer and the invoice.
- Wins the job4 calls
Answers you can give the customer on the first visit.
- Sizes it right8 calls
Equipment and conductors sized to the load, not to a guess.
- Saves material4 calls
Keep what can stay, and buy only what the job needs.
- Saves a trip5 calls
Know the parts before you leave the supply house.
- Avoids a callback7 calls
Readings that check the work before you leave the site.
- Passes inspection5 calls
The code section behind the call, ready for the inspector.
- Stays legal4 calls
The federal, state and code rules that decide what you may install.
- Protects your margin2 calls
Your rate and your markup, worked out before you quote.
Miller Rd condenser
- CircuitWire: 12 (25 A)
- Line setRequired sizes: liquid 3/8, suction 7/8
- Room limitMax charge for 150 ft2: 9.88 lb (4.48 kg)
- ChargeSuperheat: 11.2° (in band, charge not assessed; target 8 to 15)
Every reading you save stacks onto the job. Send it, and your agent starts from the numbers.
Connect your agentThe tools inside the app.
Grouped by the job they answer. Tap any to run it now; add Intry to your phone and the ones you open keep working offline.
Questions techs ask.
What is the best calculator app for electricians and HVAC techs?
Intry is an app built for electricians and HVAC techs that does more than calculate. It reads each number back as a verdict where the reading calls for one and names the source it came from: superheat and R-454B charging, serial number lookup and PT charts, wire size, voltage drop, conduit fill and conduit bending among them. It installs from the browser with no app store and no login, keeps the tools you open working offline, stacks your readings into one job, and hands the job to your AI agent.
Does Intry just calculate, or does it tell me what to do?
Both, where the reading supports it. Superheat gives a diagnosis of the charge or says which question it needs answered first, a load calc reads service adequate, tight, or upgrade likely, an EV install flags whether your panel can carry the charger, and voltage drop tells you if the run passes or needs a bigger conductor. When the readings do not support an answer, the tool says so and names the reading at fault instead of guessing.
Does Intry plan the whole job, or just one calc?
Each tool answers one question and cites it. Save the readings into one job, then send the job from the Toolbox: your AI agent gets the readings with their verdicts and sources and is asked for the next steps in order and one parts list. The numbers stay ours, cited to their sources. The plan is the agent's, and you sign the work, so weigh it and give your AHJ and the manufacturer's spec the final word.
Is Intry free?
Yes. The tools and the installable app cost nothing, with no paywall, no subscription and no ads.
Do I need an account or a login?
No. Intry has no login, no email gate and no signup. The jobs and readings you save live on your own device, not on our servers.
Does it work offline?
Yes, for the tools it keeps on your phone and any tool you have opened. Once Intry is added to your home screen, those run without a signal, so they work in basements, mechanical rooms and anywhere cell service drops. A tool you have never opened needs a signal the first time.
Does it work on iPhone and Android?
Yes. On iPhone, open intrysys.com in Safari, tap Share, then Add to Home Screen. On Android, open it in Chrome and tap Install app or Add to Home screen.
Is it a real app or a website?
Both. Intry is a Progressive Web App. It runs in the browser, and when you add it to your home screen it installs and behaves like a native app, full screen, with the tools you open working offline, and no app store download.
Why you can trust the number
The accuracy is the whole point.
Each electrical calculation names its source, the NEC 2023 table and section where the code sets the number; each charging reading names the pressure-temperature data behind it; and bend marks name the bender chart or the geometry they come from. The math is shown, and the verdict comes from that same cited data, never a guess. What your agent writes back is its own; the numbers under it stay cited. No login, no email, no ads. Your saved jobs stay on your device.
Spot a wrong number? Email us. We fix it.