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AC Repair & Precision HVAC Engineering | Baytown & Mont Belvieu

Most contractors swap parts. We solve the root cause—backed by Manual J load calculations and custom fabrication.

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Engineering, Not Guesswork

Why Coastal Texas HVAC Requires Engineering, Not Just Service

In the humid, salt-heavy environment of the Texas Gulf Coast, standard HVAC service isn't enough. Equipment fails faster here. Humidity penetrates deeper.

Every job starts with data, not a guess — so you pay for the fix you actually need.

2022
Established

Get Your Free Diagnostic Assessment

Tell us what's happening — we'll respond with no pressure and no scare tactics.

What We Do

Residential, Commercial & Construction Services

Precision AC Repair

Problem

Most AC repairs start with a guess and end with a parts swap — warm air, short-cycling, spiking bills, or musty vents are often symptoms of airflow, refrigerant, or load problems, not the whole story.

Engineering Fix

Root-cause diagnostics first: we measure static pressure, amp draw, refrigerant charge, and airflow before replacing any component, then repair with verified performance — not a power-on-and-leave parts swap.

What We Measure
  • Static pressure
  • Amp draw
  • Refrigerant charge
  • Airflow and temperature differential
Service Details →

High-Efficiency Installation (Manual J)

Problem

Oversized or mis-sized systems short-cycle, fail to control Baytown humidity, and drive energy bills up — especially as coastal salt and sulfur accelerate coil corrosion on aging equipment.

Engineering Fix

Every installation starts with a Manual J load calculation and engineered duct design — right-sized equipment, airtight custom ductwork, and commissioning that verifies the system holds 75°F under real load.

What We Measure
  • Manual J load calculation
  • Insulation and envelope assessment
  • Static pressure verification
  • Amp draw at commissioning
Service Details →

Humidity Control & IAQ

Problem

Musty odors, window condensation, clammy indoor air, or allergy flare-ups point to latent load and air quality problems a thermostat alone cannot fix.

Engineering Fix

Measurement-first IAQ engineering — we assess sensible and latent load, then design filtration, dehumidification, or ventilation matched to your home's actual conditions.

What We Measure
  • Indoor humidity levels
  • Latent vs sensible load profile
  • Filtration and ventilation requirements
  • Post-install IAQ verification
Service Details →

Ductless & Smart Zoning

Problem

Single-zone systems leave some rooms too hot while others over-cool — uneven loads and leaky ductwork waste conditioned air in spaces nobody is using.

Engineering Fix

Manual J–sized ductless or smart zoning: each zone matched to its sensible and latent load, commissioned with verified static pressure and amp draw.

What We Measure
  • Per-zone Manual J sizing
  • Static pressure at commissioning
  • Amp draw verification
  • Independent zone performance testing
Service Details →
Built Different

The Difference Between a Mechanic and an Engineer

Most HVAC companies swap parts and hope the symptom goes away. We measure first — because the fix you actually need starts with data, not a guess.

The Mechanic
The Engineer
Hears "no cold air" and swaps the capacitor.
Measures static pressure and amp draw, traces undersized ductwork or a refrigerant fault, and fixes the root cause — not the symptom.
Sizes the replacement unit to "whatever was there before."
Runs a Manual J load calculation against your home's actual envelope, insulation, and duct layout.
Treats humidity as a thermostat problem.
Engineers latent load separately — dehumidification, airflow, and filtration sized for Gulf Coast conditions.
Powers on, collects payment, and moves to the next call.
Verifies temperature differential, airflow, and amp draw before calling the job finished.
Uses off-the-shelf duct fittings that leak at the seams.
Fabricates custom sheet metal in-house for airtight transitions that hold static pressure.
The Difference

Why Service Line Air & Heat?

  • Root-Cause Diagnostics

    We don't replace parts until we know why they failed. Amp-draw testing, static-pressure measurement, and refrigerant analysis — every repair starts with data.

  • Manual J Load Calculations

    We size systems to your home's actual thermal load, not the 'same tonnage' guesswork that causes short-cycling and high bills.

  • In-House Sheet Metal Fabrication

    Custom ductwork fabricated in-house for a proper fit on every project — no off-the-shelf compromises.

  • Coastal Corrosion Protection

    Built for the Gulf Coast: we spec and protect equipment against the salt-heavy, humid coastal air that fails standard installs early.

  • 75°F Guarantee

    If we design it, we guarantee it holds 75°F in your home on the hottest August day — or we make it right.

Michael Jarrell, Owner & Lead Engineer
Meet the Owner

Michael Jarrell

Owner & Lead Engineer

  • Texas State HVAC License
  • Industrial Electrician Certificate
  • A2L Refrigerant Certified
  • EPA 608 Universal Certified
Michael Jarrell is a second-generation HVAC professional who started working alongside his father at age 12 in Southwest Louisiana. After graduating from Sowela Technical Community College he earned his Industrial Electrician Certificate — a credential most HVAC technicians don't pursue — which lets Service Line Air & Heat diagnose complex commercial systems, server-room cooling failures, and electrical issues other contractors refer out. He founded Service Line Air & Heat in 2022, bringing two decades in the industry to the Baytown area and Houston Ship Channel corridor.
More About Us
Questions

Frequently Asked Questions

Most HVAC companies are parts swappers — they pull a unit, drop in the same tonnage, and call it a day. We engineer climate solutions. Every project starts with a Manual J load calculation to right-size the system for your specific home, not a rough guess based on square footage. We fabricate our own airtight ductwork in-house using custom sheet metal, so there are no off-the-shelf fittings leaking conditioned air into your attic. We also bring Industrial Electrician Certification to every job, which means we measure amp draw and static pressure before we ever quote a repair. Root-cause diagnostics first — not high-pressure sales. And because we understand Baytown's coastal environment — the salt and sulfur from the petrochemical corridor that accelerate coil corrosion — we engineer specifically for this climate. That's what Built, Not Bought means in practice.
A Manual J load calculation is the engineering foundation of a correctly sized HVAC system. Without one, contractors typically default to "same tonnage as the old unit" — which is often wrong from the start. An oversized system short-cycles : it cools the air temperature quickly but shuts off before it can pull humidity out of your home. In Baytown's climate, that means a house that reads 75°F on the thermostat but feels like 80°F because the latent load — the moisture — was never addressed. An undersized system runs constantly, drives up your energy bill, and wears out years ahead of schedule. Manual J accounts for your home's thermal envelope , insulation values, window exposure, occupancy, and sensible versus latent load. The result is a system that's sized to match your actual heat gain and humidity — not the last contractor's best guess. That precision is what makes the 75°F Guarantee possible.
Twice a year is the standard recommendation — once before cooling season and once before heating season. In the Houston area, we'd argue the pre-cooling tune-up is the more critical of the two, given that your system may run nearly year-round under heavy load. A proper service visit isn't just a filter swap. It should include static pressure and Total External Static Pressure (TESP) measurements to confirm airflow is within design specs, an amp draw check on the compressor and motors to catch early electrical wear, coil inspection for the early signs of formicary corrosion — the pitting caused by formic acid common in coastal environments — and a refrigerant charge verification. Catching a compressor drawing high amps or a coil showing early corrosion costs a fraction of what an emergency replacement does mid-July. Preventive maintenance here isn't a sales upsell; it's straightforward engineering economics.

Ready For A Precision Solution?

Stop paying for guesswork. Partner with the engineers at Service Line Air & Heat.

Call (346) 533-0804