Superheat Calculator

1,020 primary documents33,163 automated checks

The decision engine for HVAC and electrical.

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

Field answers from the primary documents the trades run on, each with its source. Save a reading, and it stacks into the job you come back to.

HVACElectricalConnect your agent
JobMiller Rd condenser4 readings
  1. Circuit
    Wire
    #12 AWG CU (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 AWG CU conductor, and on this circuit that is correct.

  2. Line set
    Required sizes
    liquid 3/8, suction 7/8
    Carrier LLG-R454B-01 (R-454B charge adjustment)
    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° (within Title 24's default, charge not assessed; target 4 to 25)
    Subcooling
    10.8° (measured, not graded)
    Chemours Opteon XL41 (R-454B) thermodynamic properties table, liquid (bubble) and vapor (dew) columns
    Superheat within Title 24's default, 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 AWG CU (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 AWG 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

Every reading is a brick in the job.

A code, maker or federal answer comes from its primary document and names it. Save it, and it stays with the job for the next tool.

  • From the source

    Computed from the code book, the maker's manual or the federal rule, and named on the answer.

  • The math shown

    Open the steps behind a wire size or a load calc, with the section behind each table and rule.

  • Saved, it comes back

    A saved reading keeps its source and a link back to its tool, which reopens it on the sizing tools.

  • It stacks

    Readings build one job: a report for the homeowner, a panel schedule, a material takeoff.

The ToolboxPanel scheduleMaterial takeoffIntry Verified

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 forThe full map: 44 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 library1,020 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 numbers33,163

    Together they re-derive our calculators' numbers from locked source modules and check them against what they cite: the cited NEC section (2023, or the 2020 or 2026 where a tool takes the edition), manufacturer data, industry standard, federal rule, or bend geometry. The number a tool here gives you was checked against its source for the cases our checks cover. 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 cited NEC section (2023, or the 2020 or 2026 where a tool takes the edition), manufacturer data, industry standard, federal rule, or bend geometry. 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, for the cases our checks cover, before it reached you, and a tool's page links its sources so you can check it yourself.

    Latest releaseOct 26, 2026, 5:10 AM EDT
  2. The engines132 tools, charts and answers

    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 62 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 within Title 24's default, 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 (75°C-marked terminations; #4 Cu at 60°C or NM-B), 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, its insulation and its equipment groundWhat size conduit carries it?Conduit fillDefault reading7.5% 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.
Browse all tools

What Intry is

Intry is the decision engine for HVAC and electrical work. Intry computes from the primary documents the trades run on, names the source on the answer, and keeps each reading you save so the next tool, the job and your agent can build on it. 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 1,020 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, and 33,163 automated checks re-derive the calculators' numbers on every build. Readings from different tools stack into one job on your device, and the job becomes a report for the homeowner, a panel schedule or a material takeoff. 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 33,163 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 1,020 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 calculators compute from the NEC 2023 (NFPA 70-2023) and name the article and table each step used, for example 310.16 ampacity, 250.122 grounding and Chapter 9 conduit fill. Rough-in by room takes the 2020, 2023 or 2026 edition, the outdoor HVAC GFCI answer reads the 2020, 2023 or 2026 text, whichever your state enforces, and points an older edition to its own section, and the 2026 changes page reads the 2023 and 2026 books side by side. Each edition is read from its own book. The bending tools compute from bender charts and geometry, with the bend radius from NEC Chapter 9 Table 2.

What happens to a reading I save?

It goes into a job on your device with its source, its verdict where the tool gives one, and a link back to its tool, HVAC or electrical; on the sizing tools, such as wire size, load and conduit fill, that link reopens the reading itself. Readings from different tools stack in the same job: the Toolbox turns the job into a report for the homeowner, saved wire size, sub-panel, motor, MCA/MOCP and rough-in readings fill a panel schedule, and the job's wire, raceway and boxes come out as a material takeoff. The sizing tools also work a saved reading again from its inputs when you open the job, and say so if today's answer differs. On the tools that carry them, Copy for job notes copies a reading as text and Send to my phone carries it to your phone by QR code. There is no account: the job stays on your device.

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?

The tools are free: 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.

What your office software would know if it ever left the office.

Your office software knowsIntry knows
the customer's addresswhether their panel takes the new load
the appointment timethe superheat at the condenser
the unit's model numberhow old it is, and which refrigerant era it's from
the invoice totalthe 125 percent that sized the circuit
that the job is donethe readings behind it, each with its source

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.

Open the toolbox

No login. No paywall. No spam.