Committed to Comfort and Excellence Since 1972

For over 54 years, Proudly Black-owned and veteran-owned Diagnostic Heating & Cooling has delivered trusted HVAC and Electrical services with integrity, professionalism, and pride in every job.

Our Legacy of Excellence in Heating and Cooling

At Diagnostic Heating & Cooling, we've built our reputation on trust, expertise, and putting our best foot forward for the customer in front of us. As a proudly Black and veteran owned, family-run business, we combine decades of experience with modern tools to deliver honest HVAC and electrical solutions. We're proud to be a trusted name for homes and businesses throughout St. Louis and the surrounding area.

Your Peace of Mind, Guaranteed

Why St. Louis Chooses Diagnostic Heating & Cooling

With over 54 years of combined experience, we’re committed to providing top-notch service and solutions.

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Experienced Team

For over 54 years, we’ve been in the HVAC Industry.

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HVAC & Electrical Experts

One licensed team for your heating, cooling, and electrical. We diagnose the real problem and fix what actually needs fixing.

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Licensed, Insured & Bonded

We meet the highest local and regional standards, and use only certified products.

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Competitive Pricing

Fair, upfront pricing you can count on. You'll know the cost before we start.

Diagnostic Cares — Maintenance Plans

Preventative maintenance for any brand of heating and cooling system

Most breakdowns don't come out of nowhere — they come from small things a regular tune-up would have caught. Diagnostic Cares keeps your system running efficiently, catches problems early, and helps it last longer. Whatever brand you have — Trane, Carrier, Rheem, Lennox, Goodman, anything — we service it.


Two residential plans plus dedicated commercial coverage — one goal: no surprises. Cares covers the essentials; Cares Pro is complete, year-round care.

Residential plans

Diagnostic Cares Diagnostic Cares Pro
Monthly ✓ ✓
Annual ✓ ✓
Seasonal inspections ✓ ✓
Full system diagnostics (airflow, gas pressure, refrigerant) ✓ ✓
Filter inspections & changes ✓ ✓
Thermostat inspection + free battery changes ✓ ✓
Cooling coil deep cleaning (inside & outside) — ✓
Furnace cleaning — ✓
Priority scheduling — ✓
Expedited service within 48 hours — ✓
20% off parts — ✓
Works on any brand ✓ ✓

What's included

Diagnostic Cares — $39.99/month or $350/year

Our foundational plan — everything a system needs to stay healthy and reliable. Two visits a year, timed to catch problems before the seasons that stress your system most, so you're covered through both summer and winter:

  • Spring AC inspection and fall furnace inspection
  • Full system diagnostics — airflow test, gas pressure test, and refrigerant pressure/temperature test
  • Filter inspections and changes
  • Thermostat inspection with complimentary battery changes
  • Service on any brand



It's the smart baseline for a well-maintained home.


For homeowners who want deep cleanings, priority service, and parts savings on top of the essentials, that's where Cares Pro comes in.

Diagnostic Cares Pro — $59.99/month or $650/year

Complete, year-round care. Everything in Diagnostic Cares, plus:

  • All-season coverage — four inspections a year
  • Cooling coil deep cleanings, inside and outside
  • Furnace cleanings
  • Priority scheduling — you go to the front of the line
  • Expedited service within 48 hours
  • 20% off parts on any repair


Why upgrade to Pro? A second inspection tells you how your system is doing — but Pro actually makes it better. The deep coil and furnace cleanings extend your system's life and lower your energy bills (an inspection alone can't do that). Priority scheduling and 48-hour service mean you're never stuck waiting in a heat wave. And 20% off parts puts real money back in your pocket on any repair. Cares keeps you safe; Pro keeps you ahead.

Free with every new system

Every new system we install includes two full years of Diagnostic Cares — free. No surprise service bills, no wondering who to call.


Want the white-glove version? For just $25/month more, upgrade those two years to Cares Pro — priority service, deep cleanings, and 20% off parts. Most manufacturer warranties require documented annual maintenance to stay valid, so Pro also keeps your warranty on record and your investment protected.

Commercial plans

Diagnostic Cares Commercial

Complete year-round maintenance for your commercial systems — the same comprehensive care as our residential Pro plan:

  • Four seasonal service visits per year
  • Full system diagnostics — airflow, gas pressure, refrigerant pressure/temperature
  • Filter inspections and changes
  • Cooling coil deep cleanings, inside and outside
  • Furnace cleanings
  • Priority scheduling and expedited service within 48 hours
  • 20% off parts
  • Service on any brand


Pricing: inquire for a quote — based on your equipment and facility.

Diagnostic Cares Commercial Pro

Everything in Commercial Cares, plus around-the-clock protection for operations that can't afford downtime:

  • 24/7, round-the-clock service
  • Waived or discounted emergency service charges
  • All Commercial Cares inclusions


Pricing: inquire for a quote.


Why Commercial Pro? For a business, a system down means lost revenue — a restaurant with no cooling or an office with no heat can't wait until morning. Commercial Pro's 24/7 coverage and waived emergency charges mean help is on the way any hour, without the after-hours surprise on your bill.

Why a maintenance plan pays off

  • Avoid the breakdown. The cheapest repair is the one you never need.
  • Protect your warranty. Documented annual maintenance keeps manufacturer coverage valid.
  • Lower bills, longer life. A clean, tuned system runs more efficiently and lasts longer.
  • Protect your household or livelihood. Seasonal inspections flag carbon monoxide leaks, gas issues, and electrical faults early — before they become dangerous.


Ask us to get started, or call (314) 816-2016.