What should I ask before hiring an HVAC company?
One question filters out more bad HVAC installs than any other: Will you do a Manual J load calculation before sizing the equipment? An oversized AC causes short-cycling, humidity problems, and premature failure. An undersized one runs forever and never cools. If a company sizes your system by square footage alone — without load calc — they're guessing with your $8,000–$16,000.
The other critical filter: <strong>Show me the photo of the cracked heat exchanger.</strong> A real heat exchanger crack is a genuine CO risk, but it's also one of the most commonly fabricated findings in the industry. Legitimate companies carry a camera scope for exactly this reason — a diagnosis without documentation is not a diagnosis.
The questions that separate pros from problems
Will you do a Manual J load calculation before recommending equipment size?
Load calculation: included in a legitimate quoteGood answer sounds likeProper HVAC sizing requires accounting for square footage, insulation, window area, orientation, and local climate — not just square footage. A company quoting a system size in the first five minutes hasn't done this.
Walk away if…Ask specifically whether they use Manual J (the industry-standard load calculation). If they say 'we use a rule of thumb' or size by square footage alone, their equipment recommendation can't be trusted.
Are your technicians EPA 608 certified to handle refrigerant?
Leak search: $200–$450; correct fix vs. recurring top-offGood answer sounds likeHandling refrigerants (R-410A, R-454B, R-22) is federally regulated by the EPA. Technicians must hold EPA 608 certification. Companies that top off refrigerant without finding the leak are running a recurring upsell — not fixing the problem.
Walk away if…Ask for EPA 608 certification. Then ask: 'If the system is low on refrigerant, how do you find and fix the leak?' A tech who just tops it off without locating the leak is scheduling your next service call.
If you find a cracked heat exchanger, how do you document it?
Furnace replacement: $4,500–$9,000Good answer sounds likeA cracked heat exchanger is a real CO risk — but it's also one of the most commonly fabricated findings used to sell furnaces. A legitimate company carries a scope camera and will show you the crack on screen.
Walk away if…Ask this question before scheduling. If they say 'we'll show you documentation,' that's the right answer. If they're vague, that's your tell.
Do you pull permits for system replacements?
Permits: $150–$400Good answer sounds likeFull HVAC system replacements require permits in most jurisdictions. Unpermitted systems can fail home inspections and affect homeowner's insurance coverage.
Walk away if…Ask which permits apply. The company should pull them — not tell you to 'handle it yourself.'
What's included in the quote — equipment, installation, and ductwork inspection?
Full system install: $6,000–$16,000 depending on typeGood answer sounds likeSome companies quote the equipment only and bill ductwork, electrical upgrades, and refrigerant separately. Others include everything. The difference can be $1,000–$3,000.
Walk away if…Ask for a written quote that specifies what's included: equipment brand and SEER rating, refrigerant charge, electrical disconnects, duct sealing, and haul-away of old equipment.
Is the tune-up coupon a loss leader for upsells?
Capacitor: $150–$300 (legit); compressor: $1,200–$2,500 (verify)Good answer sounds like$49–$79 tune-up coupons that consistently produce urgent repair findings on systems that were working yesterday are a documented business model in HVAC — not a coincidence.
Walk away if…If a tune-up tech tells you your capacitor, contactor, or heat exchanger needs immediate replacement, ask to see the meter reading or photo that shows the failure. A capacitor replacement is $150–$300 — legitimate; a compressor quote after a coupon visit is a red flag.
Before you even call
- Change your filter before calling — a dirty filter is the #1 cause of HVAC short-cycling and reduced cooling, and takes 30 seconds to check. If the problem resolves, you saved a service call.
- Write down the system's age (usually on the data plate on the outdoor unit), the model and serial number, and any error codes shown on the thermostat. HVAC techs can pre-research parts availability before arriving.
- If you're getting a new system quote, check whether your home qualifies for the IRA heat pump tax credit (up to $2,000 through 2032) — this can meaningfully affect the repair-vs-replace math.
- Get at least two quotes for any system replacement. The range between the highest and lowest bid is often $2,000–$4,000 for the same brand and SEER rating.
Unlock the hiring checklist
Use this before you call an hvac, so you know what to ask and what to avoid.
Red flags that end the conversation
- Any HVAC company that quotes a new system size without doing a Manual J load calculation — equipment sized by square footage alone can be 30–50% wrong in either direction.
- A tech who recommends full furnace replacement because of a 'cracked heat exchanger' but can't or won't show you photo or scope documentation of the crack.
- Refrigerant has been topped off two or more times without the company locating and fixing the source of the leak — they're selling you a recurring service call, not a repair.
- A $49 tune-up coupon visit produces a quote for a compressor replacement or new system on a system you had no issues with before the visit.
About pricing
HVAC equipment quotes should itemize: equipment brand, model, and SEER/SEER2 rating; installation labor; refrigerant charge; permit fee; electrical disconnect if needed; duct connection and sealing; and haul-away of existing equipment. Ask whether the quote includes a duct leakage check — leaky ducts reduce system efficiency by 20–30% and are commonly missed. For heat pump quotes, confirm whether the quote includes the air handler or is outdoor-unit-only.
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Related questions
What certifications should an HVAC technician have?
At minimum: EPA 608 certification for refrigerant handling (federally required), and NATE (North American Technician Excellence) certification is a strong indicator of competency. State contractor licensing varies — check your state contractor board. An unlicensed crew installing a new system can void manufacturer warranties.
How much of a deposit should an HVAC company require?
For equipment orders and full system installs, 25–50% upfront is common and reasonable — equipment has to be ordered and is non-returnable. For service calls and repairs, no deposit is standard. Always get a written quote before any payment changes hands.
How do I know if my system is covered by a maintenance warranty?
Most equipment manufacturers offer 5–10 year parts warranties that require registration within 60–90 days of install. Some require annual professional maintenance to keep the warranty valid. Ask the installing company to register the equipment on your behalf and provide you with the registration confirmation.
What is a SEER2 rating and does it matter when comparing quotes?
SEER2 is the updated efficiency standard (replacing SEER in 2023) — higher is more efficient. For central AC, 15–18 SEER2 is the current mainstream range. Two quotes with different SEER2 ratings aren't directly comparable on price alone — calculate the annual operating cost difference over the system's life before deciding if the efficiency upgrade pencils out.