Live dispatch · Coastal SD systems online
engineering@coastlinehvac.com · (858) 550-3810
San Diego · Climate Engineering

Calibrated systems.
Measured comfort.

Modern HVAC engineering for coastal San Diego. We diagnose with instruments, install to spec, and document everything. No mystery surcharges, no oversold equipment, no rule-of-thumb sizing.

License
C20-728K
Response
~28 min
Reviews
4.94 / 5
Outdoor · 67°F · Clear
System balanced
72°F
Cool · Auto
RH 52%
Dew 49°
Load 38%
— Live system display
Sample residence · La Jolla · 2-zone heat pump
— Self-Diagnostic

What's wrong
with your system?

Select a symptom — we'll show you what we'd actually check, the most likely causes ranked by frequency, and what a typical fix runs. This is the same diagnostic logic our techs follow when the truck arrives.

— Select a symptom
— 01
Hot upstairs / cold downstairs
— 02
AC running but not cooling
— 03
System short-cycles every few minutes
— 04
Strange noise from outdoor unit
— 05
Higher than normal energy bill
— 06
Musty smell when system runs
— 07
Thermostat won't reach setpoint
— 08
Water leaking from indoor unit
coastline-diag — v2.4 — sample.lajolla.local
Online
Time on site
Cost range
First-visit fix rate
Warranty
live.diag.stream /dev/sensor0 · 9600 baud
— Services

What we install
and service.

Residential and small-commercial HVAC for coastal San Diego. Heat pumps, mini-splits, ducted systems, indoor air quality — sized by Manual J load calc, not by gut feel.

— 01

Heat pump install & replace

Manual J load calc, equipment sizing, refrigerant lines, commissioning report. Most full systems installed in 1–2 days.

From $8,400 · 10-yr parts · 2-yr labor
— 02

Mini-split & multi-zone

Ductless and zoned solutions for additions, ADUs, and homes without existing ductwork. Mitsubishi and Daikin diamond installer.

From $4,900 · 12-yr parts
— 03

Ductwork & airflow

CFM measurement at every register, leak testing, sealing, replacement. Most thermal-imbalance issues are duct issues, not equipment issues.

From $640 · diagnostic included
— 04

Diagnostic visit

Symptom-based diagnostic with manometer, refrigerant gauges, and thermal imaging. Written report. $129 fee credited to repair.

$129 flat · applied to fix
— 05

Indoor air quality

MERV upgrades, UV sanitizers, whole-home humidifiers, fresh-air ventilators. Coastal humidity calls for active management.

From $380 · most done in one visit
— 06

Light commercial

Restaurants, retail, small offices. Maintenance contracts available with monitoring, filter swaps, and seasonal startups.

Contracts from $280/mo
— Methodology

Engineered, not
estimated.

Most HVAC failures aren't equipment failures — they're sizing, installation, or duct-design failures masquerading as equipment problems. We're trained to find the actual root cause, not just replace the visible part.

Every install starts with a Manual J load calculation. Every diagnostic uses instruments, not intuition. Every job ends with a commissioning report. That's the methodology — same on a $400 repair as on a $40,000 ducted retrofit.

01Listen
Symptom intake, on the phone or in person
We start with what *you* are experiencing — not what the brochure wants to sell. Hot upstairs, weird noise, high bill — these are data points, and we treat them as such.
02Measure
Instrument-based diagnostic
Manometer at the return plenum. Anemometer at every register. Refrigerant gauges. Thermal imaging at suspected leak points. Manual J load calc if we're sizing equipment.
03Specify
Written scope, with rationale
You get a written diagnostic and proposed scope of work. Each line item is explained — why this part, why this size, why this approach over the alternatives. No surprise add-ons later.
04Document
Commissioning report on completion
Every install ends with a commissioning document — refrigerant charge, static pressure, register CFMs, final temperatures. You keep it. We keep a copy for warranty and future service.

No cooling, weird noise,
or a system on its last leg?
Let's diagnose it.

(858) 550-3810 Mon–Sat · 24/7 emergency line
Same-day · Diagnostic (858) 550-3810