Buying Guides
Questions to Ask HVAC Contractors
Quick answer
Before hiring any HVAC contractor ask five things: license and insurance verification, itemized written quotes, how they size replacement equipment, warranty terms on both labor and equipment, and who actually performs the work. For replacements, a contractor who quotes without a load calculation or duct inspection is guessing with your money.
The screening five for any job
These apply to every hire, from a $200 repair to a full replacement.
Are you licensed and insured for this work here?
Verify the state license number and ask for the certificate of insurance. Legitimate contractors provide both without friction.
Is the quote written and itemized?
Diagnosis, parts, labor, and fees broken out. Verbal totals and single number quotes hide padding and prevent comparison.
Who does the work?
Employee technicians or subcontractors, and what experience level arrives at your home. Ask whether the diagnosing tech performs the repair.
What warranty covers this work?
Labor warranty length in writing, distinct from the parts warranty. Quality shops back repairs for a year or more; 30 days signals churn work.
What happens if this does not fix it?
Honest shops explain their misdiagnosis policy, credit prior labor toward the correct repair, and put it in writing.
Replacement specific questions
System replacement is where five figure mistakes happen, and these questions prevent most of them.
- Will you perform a Manual J load calculation? Sizing by matching the old unit or by square footage rules of thumb perpetuates 50 years of oversizing, and an oversized system short cycles, dehumidifies poorly, and dies young
- Will you inspect and test the ductwork? New equipment on leaky ducts wastes 20 to 30 percent of what you just bought; static pressure readings should inform the quote
- What exact model numbers am I buying, and do they qualify for current tax credits and rebates? Get AHRI matched system numbers in writing
- What does commissioning include? Refrigerant weighed to spec, airflow measured, static pressure documented, combustion analyzed. A startup checklist you receive a copy of separates professionals from installers
- What are my good, better, best options? A single option quote is a sales tactic; efficiency tiers with honest payback math is consulting
Red flags that end the conversation
Walk away from: pressure to sign today with expiring discounts, refrigerant topping without leak diagnosis on repeat visits, condemnation of equipment without showing you the failure, cracked heat exchanger claims without photographic or camera evidence, quotes wildly below competitors, which fund themselves through skipped commissioning and vanishing warranties, and any request for full payment before work begins. On the positive side, the contractor who measures things, photographs findings, explains options without urgency, and quotes in writing is the one worth a premium; installation quality determines more of your system's life than any brand decision.
Frequently asked questions
How many quotes should I get for HVAC replacement?
Three written quotes is the practical standard: enough to see the market range and spot outliers in both directions. Compare scope line by line, load calculation, duct work, model numbers, commissioning, and labor warranty, not just totals, because the cheapest quote usually removes the invisible quality steps.
Should I hire the company that maintained my old system?
Familiarity has value, but replacement is a different skill than maintenance and a five figure purchase deserves competitive bidding. Include them in your three quotes, and judge every bidder on load calculation, commissioning practices, and installation warranty rather than incumbency.
What certifications should an HVAC technician have?
EPA Section 608 certification is federally required for refrigerant work and nonnegotiable. NATE certification signals tested competence and is worth preferring. For installations, factory certifications matter mainly for premium and inverter equipment where brand training genuinely affects quality.
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