Feature spec
Goal: Send a clear invoice after finishing a job.
- Add a client, line items, a due date, and payment instructions.
- Preview the total before exporting a PDF.
- Keep an editable draft if export fails.
App Overview
Superheat & Subcool Calc
HVAC Superheat & Subcool Calculator is the professional field diagnostic tool for AC service and system commissioning
$0.99 · In-app purchases
PRICE
$0.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 1.0
1 ratings · Below Average
Evidence scope: No current overall US chart position is available. Category-chart positions shown in discovery are a separate scope. Revenue is a directional model estimate, not verified earnings.
Build your own version
Build Kit
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A product spec, screen plans, and build steps for your coding agent.
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What's included16 files
A product spec, phased build plan, differentiation notes, and screen references.
- START_HERE
- AGENTS
- EVIDENCE
- SPEC
- BUILD_PLAN
- DIFFERENTIATION
- skills/
- screens/
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Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.
Screen plan
Invoice editor: Client at the top, editable line items in the middle, total and preview action at the bottom.
States: Empty draft, validation errors beside each field, exporting, and a retry action that preserves the draft.
Differentiate and validate
Hypothesis: Contractors need faster repeat invoices more than more templates.
First experiment: Test duplicating a previous job with five contractors. Watch where they hesitate before expanding the feature set.
The full kit adds a phased build plan, evidence notes, tool prompts, and implementation guidance. It is a plan for your coding agent, not a finished app.
Usage: Mechanics are fair game; never reuse the original name, branding, assets, or verbatim copy.
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Free quick prompt For a smaller starting point
Quick prompt
Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.
// RORK SYSTEM PROMPT
Rork plan preview for Superheat & Subcool Calc: map the core Utilities workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
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Opportunities
AI-GENERATED OPPORTUNITY HYPOTHESES
These are generated suggestions, not verified review quotations. Check current App Store reviews and speak with users before treating a possible gap as a requirement.
Hypothesis 1
Ensure robust input validation and clear error messaging.
Assumption to check: Poor user reviews due to lack of functionality and bugs.
Validate with people who use this workflow before building.
Hypothesis 2
Include a wider range of refrigerants and customize options.
Assumption to check: Limited refrigerant options.
Validate with people who use this workflow before building.
Hypothesis 3
Implement a more intuitive layout and clear navigation cues.
Assumption to check: Confusing navigation and layout.
Validate with people who use this workflow before building.
App evidence
Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.
App Store description
HVAC Superheat & Subcool Calculator is the professional field diagnostic tool for AC service and system commissioning. Calculate superheat, subcooling, and saturation for 10 refrigerants including R-410A, R-454B (EPA 608 transition), and R-32 with smart charge diagnostics and color-coded results for instant field diagnostics. FEATURES: Instant Superheat & Subcooling Calculation - Get results in seconds Smart Charge Diagnostics - Normal, Low, or High with recommendations 10 Refrigerants Supported - R-410A, R-22, R-454B, R-32, R-407C, R-134a, R-404A, R-507A, R-290, R-717 Metering Device Support - TXV (expansion valve) or fixed orifice Color-Coded Results - Green/yellow/red for quick decisions P-T Saturation Data - NIST REFPROP-grade, verified against manufacturer charts Zeotropic Blend Support - Correct bubble/dew handling for blends 100% OFFLINE: All refrigerant data built-in. Works on job sites without cellular coverage. HOW IT WORKS: 1. Select refrigerant (R-410A, R-454B, R-32, etc.) 2. Select metering device (TXV or fixed orifice) 3. Enter suction pressure & temperature 4. Enter liquid pressure & temperature 5. Get instant superheat, subcooling & charge diagnosis UNDERSTANDING RESULTS: Superheat - Temperature rise above saturation on low side. Normal 10-20°F TXV, 15-25°F fixed orifice. Low indicates overcharge; high indicates undercharge or low airflow. Subcooling - Temperature drop below saturation on high side. Normal 10-20°F. Low indicates undercharge; high indicates overcharge. DIAGNOSTICS: Green - Normal charge, optimal operation Yellow - Borderline condition requiring attention Red - Undercharge, overcharge, or airflow issue SUPPORTED REFRIGERANTS: R-410A (residential), R-22 (legacy), R-454B (EPA replacement), R-32 (mini-splits), R-407C (commercial), R-134a (auto AC), R-404A (refrigeration), R-507A (low-temp), R-290 (propane), R-717 (ammonia) 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 USE CASES: AC service calls, refrigerant charge diagnostics, equipment commissioning, troubleshooting complaints, EPA 608 certification study, preventive maintenance checks, system optimization, R-454B transition preparation. PERFECT FOR: HVAC technicians, refrigeration mechanics, AC contractors, HVAC apprentices, building engineers, commissioning specialists, HVAC students. All P-T saturation data from NIST REFPROP-grade equations of state, cross-checked against manufacturer charts, covering -60°F to +150°F, with correct bubble/dew blend calculations. Part of HVACTools Suite - professional HVAC technician tools for field service and diagnostics.
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Screenshots
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Build scope
Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.
Define the first version
Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.
Set boundaries
Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.
Check the hard parts
Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.
SUGGESTED BUILD STACK
React Native
Expo
TypeScript
react-native-paper
@react-native-async-storage/async-storage
BUILD KIT DIFFICULTY
Intermediate
From the Build Kit assessment.
A reliable timeline needs an agreed scope and a technical check. Ask your agent to estimate the phases in BUILD_PLAN.md after that review.
