On this page
- HVAC Second Opinion in San Antonio: The Short Answer
- When an HVAC Second Opinion Makes Sense
- What We Check During an HVAC Second Opinion
- What About R-22 and R-410A Systems?
- How to Compare HVAC Quotes
- Our Promise
- Why Homeowners Trust Modern Air Systems for a Second Opinion
- Common Misdiagnoses We Find During an HVAC Second Opinion
- What to Bring to Your HVAC Second Opinion
- Red Flags in an HVAC Quote
- What Happens After Your HVAC Second Opinion
- Frequently Asked Questions
Modern Air Systems is a family-owned HVAC company in San Antonio. We started the business because we kept seeing homeowners pay for poor installations and unnecessary replacements. Our HVAC second opinion is simple: we check your system, explain what we find in plain language and tell you honestly whether to repair or replace.
HVAC Second Opinion in San Antonio: The Short Answer
An HVAC second opinion is an independent inspection by a different licensed contractor to confirm whether a repair or a full replacement is really needed. Get one when you are told to replace a system that is less than 10 years old, when the diagnosis came without test readings, or when you feel pressured to sign the same day. Modern Air Systems tests the original diagnosis and tells you honestly what we find.
When an HVAC Second Opinion Makes Sense
Ask for a second opinion when:
- You were told you need a new system, but it is less than 10 years old
- The diagnosis was “bad compressor” or “leaking coil” without test results
- You were quoted a much larger system than you have now
- The price changed after the technician arrived, or you felt pressure to sign the same day
- The quote does not list the equipment model numbers, size or warranty
- You were told your refrigerant is “illegal” and the system must be replaced immediately
None of these automatically means the first company was wrong. They are simply good reasons to get a second set of eyes.

What We Check During an HVAC Second Opinion
The original diagnosis
We test the part that was called out. For a compressor, that means checking electrical readings, amperage and pressures rather than taking the label at face value. Sometimes a failed capacitor, contactor or fan motor looks like a compressor problem.
Refrigerant and leaks
If a leak was found, we confirm where it is and how large it is. A small leak at an accessible fitting can often be repaired. A leaking evaporator coil on an older system can tip the decision toward replacement.
System age and condition
We look at the age of the equipment, its repair history and the condition of the coils, electrical parts and cabinet. We tell you how much life we think is left.
Sizing and ductwork
If replacement is the right call, we check whether the proposed size matches your home. A larger system is not automatically better, and leaky or undersized ducts can cause the very problems a new system is supposed to fix.
What About R-22 and R-410A Systems?
If your system uses R-22, refrigerant is scarce and expensive because R-22 has not been produced or imported in the U.S. since 2020. Replacement often makes sense for these systems, but it is not always an emergency.
If your system uses R-410A, it can still be serviced and repaired. New equipment is moving to newer refrigerants such as R-454B and R-32, but that change does not make your existing R-410A system illegal to keep or repair.

How to Compare HVAC Quotes
When you compare a second opinion with the original quote, look at:
What a complete HVAC quote should list
Use this to compare quotes side by side
| Check for | What the quote should show |
|---|---|
| Equipment | Brand, model numbers and size (tonnage) for each unit |
| Efficiency | Ratings such as SEER2 for cooling |
| Matched indoor side | Whether the indoor coil or air handler is replaced to match the outdoor unit |
| What is included | Line set, drain, pad, electrical, thermostat, permit and haul-away |
| Warranty | The contractor’s labor warranty and the manufacturer’s parts warranty terms |
| License | Whether the contractor is licensed by the Texas Department of Licensing and Regulation |
Ask every contractor for a written quote that lists these items. It makes comparing apples to apples much easier. If replacement is the answer, see what to expect from HVAC system replacement or AC replacement with us.
Our Promise
- We tell you if your system can be repaired, even if that means a smaller job for us
- We show you what we found, with readings and photos where possible
- You get written, upfront pricing before any work starts
- No pressure to sign the same day

Why Homeowners Trust Modern Air Systems for a Second Opinion
- Family-owned and run by Andy Garza, with three generations of HVAC experience in San Antonio
- Licensed and insured, Texas license TACLB27872E
- An honest, repair-first approach
- Written quotes with model numbers, sizes and warranty terms
Common Misdiagnoses We Find During an HVAC Second Opinion
Many expensive quotes start with a real symptom and the wrong cause. During an HVAC second opinion we often find:
Common misdiagnoses we find
A real symptom, an expensive guess and the actual cause
| What the first quote said | What we often find instead |
|---|---|
| Bad compressor | A failed capacitor |
| Refrigerant leak | A clogged condensate drain or a frozen coil |
| Failing system | A dirty outdoor coil causing high pressures |
| Dead system | A thermostat or wiring fault |
| Undersized system | Airflow problems from a dirty filter or blower wheel |
None of these are always the answer, which is why we test before we tell you anything.
None of these are always the answer, which is why we test before we tell you anything.
What to Bring to Your HVAC Second Opinion
- The written quote or estimate from the first company
- Any diagnosis notes, readings or photos they gave you
- The age of your system or a photo of the nameplate
- A short history of repairs and when the problem started
With that information, your HVAC second opinion takes less time and gives you a clearer comparison.
Red Flags in an HVAC Quote
- A replacement quote with no model numbers or tonnage listed
- A much larger system than you have now with no load calculation
- Pressure to sign today to keep a special price
- Claims that your current refrigerant makes your system illegal to keep
- No written warranty terms for labor or equipment
You can check any contractor’s Texas license on the Texas Department of Licensing and Regulation website before you sign.
What Happens After Your HVAC Second Opinion
If the system can be repaired, we give you a written price for the repair, and you decide. If replacement makes sense, we explain why and give you options for HVAC system replacement or AC replacement with model numbers, sizing and warranty details. Either way, an HVAC second opinion from Modern Air Systems comes with no obligation.
Frequently Asked Questions
Do you charge for an HVAC second opinion?
Ask our team about current pricing for a second-opinion visit when you book. You will know the cost before we arrive.
Can you give a second opinion from a photo of the quote?
You can send us the quote and a photo of your system’s nameplate so we can review the equipment and pricing. To confirm a diagnosis, we need to test the system in person.
Is it rude to ask for a second opinion?
No. Reputable HVAC companies expect homeowners to compare quotes on a large purchase. A good contractor will explain their diagnosis and stand behind it.
Should I repair or replace my unit?
It depends on age, the repair cost, refrigerant type and condition. A common rule of thumb is to multiply the system’s age by the repair cost; if the result is over $5,000, replacement is often the better investment.
How fast can you get someone out for a second opinion?
We schedule second opinions as quickly as we can during business hours. Call or send a request, and we will give you the next available time.
What if you agree I need a new system?
We will tell you why, show you what we found and give you a written replacement quote with model numbers, sizing and warranty details. You are never obligated to buy from us.
How long does an HVAC second opinion take?
Most HVAC second opinion visits take about an hour, depending on what needs to be tested and how easy the equipment is to reach.
Will you tell me if the first company was right?
Yes. If our testing confirms the original diagnosis, we tell you. An honest HVAC second opinion sometimes means agreeing with the first quote.
Can you give a second opinion on a new installation?
Yes. We can check a recent installation for sizing, airflow, refrigerant charge and drain setup if your new system is not performing the way it should.
Why San Antonio Homeowners Call Us
- Licensed & insured · Texas license TACLB27872E
- Family-owned, 25+ years of HVAC experience
- Upfront pricing before any work starts
Window was 9-10am and they showed up at 9am! Timing was great and the diagnostic was thorough and efficient. No upsell, just what needed attention. I’ll be calling back when I need service.
They came out, assessed the problem, and provided a solution. Repair was completed in a timely manner. Robert is a pro! Extremely satisfied.
Request Service or a Free Estimate
Tell us what’s going on and we’ll call you back, or call now: (210) 222-0201
See What San Antonio Homeowners Are Saying
Window was 9-10am and they showed up at 9am! Timing was great and the diagnostic was thorough and efficient. No upsell, just what needed attention. I’ll be calling back when I need service.
Ashley WaclawiakGoogle reviewCalled them on Labor Day bc the drain pipe was leaking. They were very responsive in spite of the holiday and were able to get to the property quickly. They were communicative and very easy to work with. They have a full report on the overall health of the system. They’ll go the extra mile for their clients. Highly recommend them
Andrea DeniseGoogle reviewCalled Modern Air, and they came out right away to diagnose and fix the problem which was a huge help in this blistering heat! Robert was awesome! He walked us through everything, then got to work immediately. Now our system is blowing super cold again. What a relief!!! We would strongly recommend Modern Air to anyone.
Sar DalGoogle reviewModern air systems replaced 2 units at my house. Not only did they give the best price, the service was first class. The owner came to inspect work and he was first class. Go with modern air!!!
Ruby CavazosGoogle reviewThey came out, assessed the problem, and provided a solution. Repair was completed in a timely manner. Robert is a pro! Extremely satisfied.
Chuck McCannGoogle reviewNeed heating or cooling help?
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