Free on the iPhone App Store

The app that helps HVAC techs figure out what's wrong.

Pick the unit, enter your readings, answer one question at a time. MasterTech ranks the likely faults, flags anything unsafe and writes the customer summary, then keeps the call on your record.

AndroidComing soon

Free to download. 5 free diagnostics every month.

See how it works

I fix systems

For technicians

Stuck on a unit? Tap through to the answer.

Pick the equipment, enter what you see, answer one question per step.
MasterTech ranks the likely faults, tells you what to test next and flags anything unsafe.
Every closed call goes on your record for the next employer.

5 free diagnostics every month. Then $9.99 a month, or nothing if your company has a plan.

More for technicians

MasterTech home screen: Evening, Marcus, a Start a call card with a Start AI Diagnostic button, recent jobs, and tool shortcuts for P/T & SH/SC, P/T Chart, Static Pressure and CFM / Airflow.

I run a crew

For contractors and company owners

See every call your crew is on. Hire the next tech from their record.

Live diagnostics as they happen, callbacks and monthly reports.
One invite code to onboard your team.
Browse open-to-work techs by certification and request an intro, all from your phone.

$29 per tech per month, unlimited diagnostics. Your techs never pay. 10+ techs? Talk to us.

More for contractors

Contractor dashboard: Good evening, with tiles for techs active, jobs closed today and open work orders, a Needs attention list with a callback and overdue PMs, and an On the clock roster.

How it works

It's 4pm. The unit is down. The customer is watching.

From broken unit to confirmed diagnosis in three steps.

Step 1

Tell it what you're looking at.

Residential or commercial. AC split, heat pump, furnace, boiler, mini split, rooftop unit, walk-in, rack system, ice machine. Pick the symptom. The app only shows the ones that fit that unit.
Step 2

Enter the readings, or just take a photo.

Suction, head, superheat, subcool, indoor and outdoor temps. Or snap the nameplate or your gauges and MasterTech reads the numbers for you.
Step 3

Answer one question at a time until it's confirmed.

Each step is one card: the single most useful test or question. Likely faults are ranked with a confidence score. Unsafe conditions stop the job. When it's confirmed, you get a customer-ready summary and a saved work order.

What's inside

One app. Three jobs.

Guided AI diagnostic

One question at a time, until it's confirmed.

Pick the unit and the symptom, enter your readings or photograph the nameplate, then answer one question per step. MasterTech ranks the likely faults with a confidence score, explains why at your level, and writes the customer summary once the diagnosis is confirmed.

STOP-WORK flags for CO, flame rollout, burnt wiring and live-circuit risk
Ranked faults with a confidence score, and the reasoning behind each
Customer-ready summary and a saved work order on every closed call

Live MasterTech working theory: three likely faults ranked with confidence bars — low refrigerant charge 45%, condenser airflow restriction 35%, restricted metering device 20% — each with the reasoning over the entered readings.

Your profile

Your work speaks for you.

Every closed call builds your record: calls resolved, years in the field, credentials like EPA 608 and NATE, notable work. Trust tier rises with resolved calls. Mark yourself open to work and contractors can find you and request an intro.

Trust Tier 1 · Getting Started → Tier 2 at 25 resolved calls
"Recruiters — see your profile" shows exactly what a company sees
Credentials are self-reported today

Contractor dashboard

See your whole crew from your phone.

What's happening now: live diagnostics as they run. Callbacks and monthly reports. Invite techs with one code and manage the roster. Find open-to-work techs by certification and request an intro. Billing for the whole team in one place.

Dashboard · Talent · Team · Account
Techs join with your invite code at sign-up
Filter open techs by EPA 608, NATE, open to work

My Team screen: the technician roster with each tech's status, calls this month, callback rate and PM completion. — Team

Find Techs

The engine

Built for the field, not a generic chatbot.

A purpose-built diagnostic engine with HVAC physics baked in: refrigerant pressure-temperature tables, superheat and subcool logic, equipment-class rules, safety rules, structured step-by-step reasoning. Explains at your level: Apprentice, Journeyman or Senior. Escalates to a stronger model on hard cases.

Not a chat box. One card per step, with tappable answers. Free text is the last resort.
Gloves-on tap targets. Dark mode for attics.
Connection drops? A standard first-checks list for that unit takes over.

Baked into the engine

Refrigerant pressure-temperature tablesR-410A, R-32, R-454B, R-22, R-134a, R-448A, R-449A, R-404A, R-407A, R-290
Superheat and subcool logicChecks your numbers against the physics and tells you when a reading contradicts your theory
Equipment-class rulesReasons only from readings that fit this unit
Safety rulesUnsafe conditions override everything else
Structured step-by-step reasoningOne highest-value question or test per step
Escalation on hard casesHands the call to a stronger model when it's stuck

Explains at your level

ApprenticeJourneymanSenior

Stop workCO · flame rollout · burnt wiring · live circuit

Field tools

The calculators you'd reach for anyway, built in.

Tap in, get the number, get back to the unit.

P/T & SH/SC
P/T Chart
Combustion
Static Pressure
CFM / Airflow
Duct Sizing
Electrical Ohm's law
Recovery Time
PM Checklist
Refrigerant Log

P/T tables built from published manufacturer charts, for residential and commercial refrigerants.

Pricing

Simple pricing. Techs on a company plan never pay.

Start free with 5 diagnostics every month. Independent techs upgrade for $9.99. Companies pay $29 per tech for unlimited diagnostics and the team dashboard.

Free

$0forever

5 guided diagnostics every month, resets on the 1st
All calculators and field tools
Your tech profile and work record

Individual

$9.99per month

or $99 a year (2 months free)

60 guided diagnostics a month
Work orders with readings, photos and a customer-ready summary
Everything in Free · cancel any time

Company

$29per tech / month

or $290 per tech a year (2 months free)

Unlimited diagnostics for every tech
Team dashboard: live calls, callbacks, monthly reports
Find Techs: hire from real work records
Your techs never pay

Running 10+ techs?

Talk to us: 214-682-1825

Download free, then pick a plan from the Billing screen in the app. Plans are purchased on the web. Cancel any time.

FAQ

Straight answers.

Is it a chatbot?

Not a chat box. Each step is one card: a question with tappable answers, a reading to enter, a test to run, or a photo to take. The engine ranks the faults and picks the next most useful step. Free text is the last resort.

Which equipment does it cover?

Residential: AC split, heat pump, package unit, mini split, furnace, boiler. Commercial: rooftop unit (RTU), walk-in, reach-in, rack system, ice machine, split system, VRF. Refrigerants from R-410A, R-32 and R-454B to R-448A, R-404A and R-290.

Does it replace the technician?

No. It can't hold the gauges. It's a second set of eyes: it checks your numbers against the physics, tells you when a reading contradicts your theory, and flags unsafe conditions. The tech confirms the diagnosis and closes the call.

What about my data?

Your readings, photos and work orders are stored in your account. Contractors see their own team only. Only techs who mark themselves open to work appear in recruiter search. Delete your account from inside the app any time. Details in the Privacy Policy.