Superheat Calculator

211 primary documents28,790 automated checks

The decision engine for HVAC and electrical.

Get the number. Know what it means. Know what to do next.

Save the readings into the job, and your AI agent can use the same Intry engines to take it further.

HVACElectricalConnect your agent
JobMiller Rd condenser4 readings
  1. Circuit
    Wire
    12 (25 A)
    Breaker
    40 A
    NEC 440.4(B) (nameplate MCA), 310.16, 110.14(C), 440.22 (MOCP), 240.6(A), 240.4(G) (Article 440), 250.122
    CHECK 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.

  2. Line set
    Required sizes
    liquid 3/8, suction 7/8
    Carrier LLG-R454B-01 Table 4 / Goodman-Daikin IOG-4047
    Reuse after flush
  3. Room limit
    Max charge for 150 ft2
    9.88 lb (4.48 kg)
    UL 60335-2-40 4th ed Annex GG / ANSI/ASHRAE 15.2-2024
    CHECK ON SITE

    This answer is for the ONE space described in this call, and this tool takes no list of spaces.

    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.

  4. Charge
    Superheat
    11.2° (in band, charge not assessed; target 8 to 15)
    Subcooling
    10.8° (in band, charge not assessed; target 8 to 14)
    CoolProp 7.2.0 reference data, bubble and dew columns
    Superheat in band, charge not assessed (needs confirmation)
Computed by the same engines your agent calls, when this page was built.

The Miller Rd condenser job, carried on by your agent

What the job turns into.

Intry settles the numbers and documents them. Your agent takes them to the supply house and turns them into the next steps.

  1. Your agent

    The parts list

    Sized from the readings above, not from memory. Give it the run lengths and it adds the quantities; anything the readings do not size, such as the disconnect, is its own call.

    Wire
    12 (25 A)
    Breaker
    40 A
    Ground
    #10 AWG Cu (Table 250.122; #8 AWG if run in aluminum)
    Charge adjustment
    add 12 oz

    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.

  2. Your agent

    Where to buy it

    With web search on, it finds the supply houses near you that list each part, so you can plan the trip.

  3. Intry

    The price, at your margin

    Work out your hourly rate and your price at your markup with Intry, then give both to your agent for the quote.

  4. Intry

    The customer's copy

    A job report the homeowner keeps, with each figure Intry calculated cited to its source.

  5. Your agent

    The next steps, in order

    What to do first, which readings interact, and what to measure before anyone guesses.

We don't build a chatbot. The best models already exist. We give them the engines.

Connect Claude, ChatGPT or another MCP agent, and it can call 23 of Intry's calculators on the same engines. A call comes back with the number, the verdict where the reading calls for one, the source, and a refusal when the engine will not grade what it cannot judge.

Send a saved job from the Toolbox and it opens Claude with the readings, their verdicts and their sources, and copies the same text for any other agent you use.

From the first reading to the parts list. Your agent takes it from there.

Connect your agentOpen the Toolbox

The calls on a job, from winning it to getting paid.

A job is a string of calls that cost or earn money. These are the ones an Intry tool answers, with a cited answer wherever a code, a standard or a manufacturer sets the number, and your agent carries each stage to the next.

Show decisions for39 decisions across 6 stages
  1. 01

    Win the job

    Your agent Drafts the repair-or-replace note for the homeowner from your readings.

  2. 02

    Size it

    Your agent Checks the models you are weighing against the load and lists what each option needs; with web search on, it can find more to check.

  3. 03

    Buy it

    Your agent Turns the readings into a parts list and, with web search on, finds the supply houses near you that list each part.

  4. 04

    Install it right

    Your agent Writes the commissioning notes from the readings you saved.

  5. 05

    Pass inspection

    Your agent Gathers the code sections your readings cite, for the inspection.

  6. 06

    Get paid

    Your agent Writes the quote and the invoice once you give it your rate and markup.

From the document to your agent.

  1. The library211 primary documents

    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.

    Automated checks behind the numbers28,790

    Together they re-derive our calculators' numbers from locked source modules and check them against the code sections, manufacturer charts, and federal rules they cite (and the structure of those tables). Use any tool here and the number you get was checked against its source first. This count is live, not a number we typed. Our own gate, and we say so.

    what this counts

    Every time we update the site, our build re-derives each calculator value from a locked source module and checks it against the exact thing it cites: the NEC 2023 section, the manufacturer chart, or the federal rule. This is our own deterministic gate, not a third-party audit. It does not make any single answer infallible. It means the math in front of you was checked against its sources before it reached you, and every number links to the source so you can check it yourself.

    Latest releaseSep 11, 2026, 6:45 AM EDT
  2. The engines115 tools, charts and answers

    Free, with no login. A tool returns the number, the verdict where the reading calls for one, and the source it came from.

  3. The jobAt least 35 tools save into a job

    Readings from different tools stack into one job on your device, each with its verdict and source.

  4. Your agent23 tools your agent can call

    Through Intry's MCP server, with setup written up for Claude, ChatGPT, Claude Code, Cursor, Windsurf, VS Code and Claude Desktop.

Nobody finishes a job with one answer.

You searched one question. The job behind it has more. Here are two jobs the way Intry links them today: each hop below is a link the product makes, and it says what it carries. Save the readings, and send the job to your agent.

The condenser call

Identify the unit, check the charge, then size the changeout.

  1. What is it, how old, what refrigerant?Serial number lookup
  2. carries the serial, and the model and refrigerant when the lookup has themIs the charge right?Superheat and subcoolingDefault reading12°F superheat, 11°F subcoolingSuperheat in band, charge not assessed
  3. carries the unit's serial and model, when the job started from oneCan the old line set stay on a changeout?Line setDefault readingFLUSH & REUSE, 7/8" / 3/8" linesReuse after flush
  4. carries the unit's serial and model, when the job started from oneCan the room hold the new refrigerant charge?A2L room limit
  5. save the readings into the jobFinish it in your agentThe refrigerant and the line set work in one list, with the room limit it has to meet.

The run

Size the wire, then check the drop, pick the raceway and bend it.

  1. What wire and breaker for the load?Wire sizeDefault reading#6 Cu, 70 A breakerSized for the load
  2. The drop
    1. carries wire, amps, length, voltage, phase and materialDoes the run hold its voltage?Voltage dropDefault reading2.88% drop, within 3%Within 3%
  3. The raceway
    1. carries the wire size and its insulationWhat size conduit carries it?Conduit fillDefault reading7.49% of 40% fill, within limitWithin fill
    2. carries the EMT sizeWhere do the marks go?Conduit bendingOffsets, saddles, stubs, and whole sticks of many bends.Default readingMarks 8" apart, 1" shrink
  4. save the readings into the jobFinish it in your agentThe wire and the conduit in one list, with the bend marks for the stick.
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What Intry is

Intry is the decision engine for HVAC and electrical work. A tool gets you the number, and where the reading calls for one it reads it back as a verdict and points at the next move, from a serial number on a condenser to the marks on a stick of EMT. The engines cite 211 primary documents on the records they ship with, and 28,790 automated checks re-derive the calculators' numbers on every build. Save readings from different tools into one job. Send the job to your AI agent, which can also call Intry's calculators through its MCP server. You sign the work, so your AHJ and the manufacturer's spec keep the final word.

Is Intry accurate?

The numbers the calculators compute come from locked source modules, not typed by hand, and 28,790 automated checks re-derive them and compare them with values recorded from the cited sources on every build. It is Intry's own gate, not a third-party audit, and it does not make any single answer infallible, so each result names its source for you to check.

Where do Intry's numbers come from?

A calculator computes from a primary document where one sets the number: the code section, the manufacturer's own manual or chart, the federal rule. Where a figure is a field rule of thumb or the tool's own band, the result says so. The count is 211 primary documents today: 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 Intry Verified page at intrysys.com/verified explains the checks.

Which NEC edition does Intry use?

The NEC 2023 edition, with the specific article and table cited on each electrical calculation (for example 310.16 ampacity, 250.122 grounding, Chapter 9 conduit fill). The 2023 to 2026 changes are tracked on their own page.

Which AI agents can run Intry?

An agent that can connect to a remote MCP server can call 23 of Intry's calculators, listed at intrysys.com/mcp, and get back the number, the verdict where the reading calls for one, and the source. Setup is written up for Claude, ChatGPT, Claude Code, Cursor, Windsurf, VS Code and Claude Desktop at intrysys.com/mcp.

Is Intry free?

Yes. There is no login, no paywall and no sign-up. Intry also installs to your phone as an app, and the tools you open keep working offline in the field.

Built for the field, not the office.

Open a tool at the panel or the condenser, keep the readings in one job, and put Intry on your phone so it works where the signal does not.

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