Your AC dies on the hottest day of July. Your furnace quits on the coldest night of January. Every single time, the urgency hits the same way: you need someone here now, and you don’t want to think too hard about who you’re hiring.
That urgency is exactly how people end up paying $8,000 for a system they didn’t need, or getting a unit that’s the wrong size for their home, or discovering six months later that a warranty they thought they had doesn’t actually cover anything. I’ve talked to homeowners who went through all three.
Knowing what questions to ask before hiring an HVAC technician is the difference between getting it right and getting taken. These 20 questions cover licensing, diagnosis, pricing, warranties, and maintenance. Pull this list up on your phone before you call anyone.
Before You Contact an HVAC Technician
Do these five things before you start calling. They’ll help you describe the problem clearly and spot bad advice immediately:
- Check your thermostat first. Make sure it’s set to the correct mode (heat or cool), the temperature is set below or above room temp as needed, and the batteries aren’t dead. You’d be amazed how many service calls end with “your thermostat was on the wrong setting.”
- Inspect your air filter. Pull it out and look at it. If it’s caked with dust and you can’t see light through it, replace it. A clogged filter causes weak airflow, frozen coils, and system shutdowns, and replacing it costs $10, not $150. Keeping a few replacement HVAC filters on hand means you can swap one in right now instead of waiting.
- Check your circuit breaker and outdoor disconnect. Both the indoor air handler and outdoor unit have their own breakers. If one tripped, reset it once. If it trips again, that’s a real problem. Call a tech.
- Look at the outdoor unit. Is it running? Is the fan spinning? Is there ice on the lines? Is the unit buried in leaves or debris? Clear at least two feet of space around it and note what you see.
- Write down your system’s brand, model number, and approximate age. This info is on a label on the indoor and outdoor units. Having it ready saves the tech time and helps them bring the right parts on the first visit.
Licensing and Experience
1. Are you licensed and insured in this state?
HVAC work involves electrical wiring, gas lines, and refrigerants that can kill people when mishandled. A license proves the technician knows local building codes. Insurance protects you when things go sideways. Ask for a license number and verify it yourself on your state’s licensing board website. It takes two minutes.
If they hesitate, get defensive, or claim they “don’t need one,” end the conversation. Seriously. Unlicensed HVAC work can void your homeowner’s insurance and leave you with zero legal recourse if something goes wrong.
2. Do you hold NATE certification?
NATE (North American Technician Excellence) is the gold standard certification in the HVAC industry. Technicians who hold it have passed rigorous exams on installation, service, and repair that go well beyond what state licensing requires.
Not every good technician has NATE certification, but having it is a strong signal. You can verify any tech’s status at natex.org. Ask which specialties they’re certified in (installation, service, or both) and which system types (air conditioning, heat pumps, gas furnaces).
3. How long have you been working on HVAC systems?
HVAC problems aren’t always textbook. A tech with five-plus years under their belt has probably seen your exact issue before and can spot what a newer tech might miss. For straightforward repairs, 3-5 years of experience is a reasonable floor. For complex jobs like full system replacements, heat pump conversions, or zoning systems, look for someone with a longer track record on that specific type of work.
4. Do you have experience with my specific system brand and type?
A tech who mostly works on gas furnaces might be out of their depth with a ductless mini-split or a geothermal heat pump. Brands have quirks, too. Diagnosing a Trane and diagnosing a Carrier can require different approaches. Ask which brands they work on most, and whether they’re an authorized dealer or service provider for yours. Authorized technicians typically get better parts pricing and direct manufacturer support, which benefits you.
Diagnosis and Repair Recommendations
5. Will you inspect my full system before recommending repairs?
Here’s a scenario that plays out constantly: homeowner calls about weak cooling, tech shows up, checks the outdoor unit, and quotes a $2,000 compressor replacement. But the actual problem? A $15 clogged air filter that was choking off airflow. Or a thermostat with dead batteries. Or leaky ductwork in the attic.
A thorough tech inspects indoor and outdoor units, checks airflow, tests electrical connections, and evaluates your ductwork before diagnosing anything. Be very cautious of anyone who gives you a firm diagnosis and price over the phone or before they’ve been inside your house.
6. What is actually wrong with my system, and how did you determine that?
You’re paying for expertise, so you deserve an explanation in plain English. A trustworthy tech walks you through the diagnostic steps and tells you specifically what failed and why. Something like: “Your capacitor is reading 32 microfarads. It’s rated for 45. It can’t start the compressor reliably anymore. I tested it with a multimeter.”
Compare that to: “It’s just old and worn out.” One answer gives you confidence. The other should give you suspicion.
7. Is it more cost-effective to repair my current system or replace it?
There’s a rough guideline called the “$5,000 rule”: multiply the repair cost by the system’s age in years. If the result exceeds $5,000, replacement starts making financial sense. But the real answer is more nuanced. It depends on your system’s efficiency rating, whether it uses R-22 refrigerant (phased out and very expensive now), how frequently it’s needed repairs, and its overall condition.
A good tech lays out both options with numbers and lets you decide. No pressure either way. If someone’s pushing hard for a $10,000 replacement when a $400 repair would buy you another 3-5 years, get a second opinion.
8. Is my HVAC system the right size for my home?
Oversized systems cycle on and off constantly. Short-cycling wastes energy, creates uneven temperatures, and wears out components faster. Undersized systems run nonstop and never reach a comfortable temperature. Either way, you’re uncomfortable and paying more than you should.
For any replacement, the technician should perform a Manual J load calculation. That’s the industry-standard method for sizing, and it accounts for your square footage, insulation, windows, ceiling height, and local climate. If someone sizes your new system by just matching what was there before, that’s a shortcut you’ll pay for.
Tip: HVAC capacity is measured in tons (1 ton = 12,000 BTUs). A typical 2,000-square-foot home in a moderate climate needs about 3-3.5 tons. But don’t rely on rules of thumb. Insist on the load calculation.
9. What SEER rating do you recommend, and why?
SEER (Seasonal Energy Efficiency Ratio) measures how efficiently a system cools. Higher numbers = less energy used. The current federal minimums are SEER2 14.3 in the South and 13.4 in the North. Premium units go up to 25+.
Here’s the honest truth: jumping from 14 to 20+ SEER doesn’t always make financial sense. In a mild climate where you barely run the AC, the energy savings might never offset the higher upfront cost. In Phoenix or Houston, a higher SEER unit can save $200-$400 per year and pays for itself in 5-7 years. Your tech should crunch those numbers for your situation, not just push the most expensive option on the wall.
Pricing and Estimates
10. Do you charge a diagnostic or service call fee?
Most HVAC companies charge $75 to $150 just to show up and figure out what’s wrong. Some waive that fee if you hire them for the repair. Others don’t. Both approaches are legitimate, but you need to know which one you’re dealing with before you book.
One thing to watch out for: companies that advertise “free diagnostics” but build that cost into inflated repair prices. Free isn’t always free.
11. Can you give me a written estimate before starting work?
Verbal estimates are worthless the moment there’s a disagreement. Get everything on paper: parts, labor, additional fees, and a timeline. You need this to compare across companies, and you need it as protection if the final bill comes in higher than expected.
Any company that won’t put a number in writing is telling you something. Listen.
12. What does this price include, and what would cost extra?
Low estimates grow fast when they exclude things like thermostat installation, ductwork modifications, permit fees, refrigerant charges, or disposal of the old equipment. I’ve seen a “$4,500 install” balloon to $7,200 once the extras were added.
Ask specifically about: thermostat, refrigerant, duct modifications, electrical work, permits, system startup and testing, and removal of the old unit. A company that includes all this in the quote without being asked is a company that respects your time.
13. Do you offer financing or payment plans?
Full HVAC replacements run $5,000 to $15,000 or more. That’s a major hit. Some companies offer 0% interest financing through manufacturer programs. Others use third-party lenders with rates that can get steep.
Ask about the interest rate, the promotional period, and what the rate jumps to when the promo ends. Compare it against a home equity loan or personal loan, because sometimes those are cheaper. And don’t forget to ask about manufacturer rebates and federal tax credits for high-efficiency systems. In 2026, those credits can offset $300 to $2,000 depending on what you install.
Warranties and Guarantees
14. What warranty comes with a new system?
Manufacturer warranties typically cover parts for 5-10 years, with compressors sometimes getting longer coverage. But here’s the catch most people miss: many warranties require installation by an authorized dealer, and many require you to register the equipment within 60-90 days or the coverage drops significantly.
Get the specific terms in writing. Ask about parts, compressor, and any conditions. And make sure the technician handles registration. Don’t leave that to yourself and then forget.
15. Do you offer a labor warranty on your work?
The manufacturer warranty covers equipment. It doesn’t cover the labor to swap out a failed part. Without a separate labor warranty, you could pay $200-$500 in labor on a system that’s technically “under warranty.” That feels like getting charged twice.
One year on labor is the minimum I’d accept. Some companies offer 5-10 years for an additional cost, which is often worth it on a new install. Get the terms in writing, specifically what’s covered for parts labor, diagnostic fees, and travel charges.
16. What is your callback policy if the repair doesn’t fix the problem?
Sometimes a fix doesn’t stick. Maybe the original diagnosis missed a secondary issue. Maybe the replacement part was defective. Either way, you shouldn’t have to pay full price for a second visit to solve the same problem.
Most reputable companies guarantee their repairs for 30-90 days. If the issue comes back, they return at no charge. Get this in writing before they start. No callback guarantee = no incentive to get it right the first time.
Maintenance and Long-Term Care
17. Do you offer a maintenance plan, and what does it include?
Regular maintenance keeps your system efficient, extends its life, and catches problems while they’re still cheap to fix. Here’s the part most people don’t know: most manufacturers require annual professional maintenance to keep your warranty valid. Skip it and you could void your coverage.
Plans typically run $150-$300 per year. What you should get for that money: at least two visits per year (one for cooling season, one for heating), priority scheduling, repair discounts, and no overtime charges. Each tune-up should cover refrigerant levels, electrical connections, coil cleaning, filter replacement, thermostat calibration, and safety controls. If a plan doesn’t include most of those, it’s not a good deal.
18. How often should I replace my air filter, and what type do you recommend?
A dirty filter is behind more HVAC service calls than any other single problem. It restricts airflow, forces the system to work harder, and can cause frozen coils and compressor damage. Replacing a $10 filter every 60-90 days prevents hundreds of dollars in repairs.
Your tech should ask about your household (pets, allergies, number of people) before recommending a filter type. Filters are rated by MERV (Minimum Efficiency Reporting Value). Higher MERV captures smaller particles, but too high can actually restrict airflow and hurt performance. Most homes do well with MERV 8-11. Homes with allergies or pets might benefit from MERV 13, but check that your system can handle it first.
19. What can I do between service visits to keep my system running well?
A tech who takes time to educate you is a tech who cares about more than the next invoice. The basics are straightforward:
- Keep the outdoor unit clear, with two feet of clearance on all sides, minimum.
- Change the filter on schedule. Set a phone reminder if you have to.
- Don’t block or close vents in rooms you’re not using (this messes with system balance).
- Watch the thermostat for unusual behavior: cycling too fast, not reaching setpoint, blank screen.
- Check the condensate drain line for clogs. A clogged drain can cause water damage and shut down your system.
None of these cost money. All of them prevent expensive problems.
20. Who should I call if I have a problem after hours or on weekends?
HVAC emergencies don’t wait for business hours. Your AC failing during a 100-degree heat wave or your furnace dying at midnight in February is not a Monday-morning problem. Ask now, before you need it, whether they have their own on-call technicians or outsource after-hours calls.
After-hours rates are typically 1.5x to 2x standard. That’s fair. What you want to know is the actual number and whether your maintenance plan includes reduced emergency rates. Save the number in your phone now, not when you’re sweating through your shirt at 2 a.m.
What to Mention or Send Beforehand
Before the technician arrives, share this information by phone, text, or email. It helps them prepare and bring the right equipment:
- Your system’s brand, model number, and age. This is on the data plate sticker on your indoor and outdoor units. If the tech knows the make and model before they arrive, they can look up common failure points and bring likely parts.
- Describe what’s happening, not what you think is wrong. “The air coming from the vents is warm when the AC is running” is more useful than “I think the compressor is bad.” Let the tech diagnose.
- Mention any recent changes. Did this start after a storm, a power outage, or a recent repair? Did you install a new thermostat, close off vents, or add insulation? Context helps the tech narrow it down faster.
- Note your fuel type and system configuration. Gas furnace with central AC? Heat pump? Ductless mini-split? Knowing this upfront prevents the tech from showing up with the wrong tools or parts.
- Explain any access issues. Is the air handler in the attic, a tight closet, or a crawl space? Is the outdoor unit behind a fence? The tech needs to know what they’re walking into.
Typical Cost Range and Factors
Here’s what you should expect to pay for common HVAC work in 2026. These are national averages, and your area, equipment brand, and job complexity will shift the numbers:
Common repairs:
- Diagnostic/service call: $75 - $150
- Capacitor or contactor replacement: $150 - $400
- Thermostat replacement: $150 - $400
- Refrigerant recharge (R-410A): $200 - $600
- Blower motor replacement: $400 - $900
Major repairs:
- Evaporator or condenser coil replacement: $1,000 - $2,500
- Compressor replacement: $1,500 - $3,000
- Heat exchanger replacement: $1,500 - $3,500
Full system replacement:
- Central AC unit only: $3,500 - $7,500
- Furnace only: $3,000 - $6,500
- Complete system (AC + furnace): $7,000 - $15,000+
- Heat pump system: $5,000 - $12,000
What drives the price up or down:
- System size (tonnage). Larger homes need larger systems, which cost more for both equipment and installation.
- SEER rating. A 14-SEER unit is significantly cheaper than a 20-SEER unit. Higher efficiency saves on energy bills but costs more upfront.
- Ductwork condition. If your existing ducts need sealing, insulating, or modifying, add $500-$2,000 to the project.
- Permits and inspections. Typically $100-$500 depending on your municipality.
- Refrigerant type. R-22 (Freon) is phased out and can cost $100-$200+ per pound. R-410A is standard and much cheaper.
- Access difficulty. Rooftop units, tight attics, and cramped crawl spaces add labor hours and cost.
Quick Reference Checklist
Pull this up on your phone when you’re ready to start calling:
- Are you licensed and insured in this state?
- Do you hold NATE certification?
- How long have you been working on HVAC systems?
- Do you have experience with my specific system brand and type?
- Will you inspect my full system before recommending repairs?
- What is actually wrong, and how did you determine that?
- Should I repair or replace my system?
- Is my HVAC system the right size for my home?
- What SEER rating do you recommend, and why?
- Do you charge a diagnostic or service call fee?
- Can you give me a written estimate before starting work?
- What does the price include, and what costs extra?
- Do you offer financing or payment plans?
- What warranty comes with a new system?
- Do you offer a labor warranty on your work?
- What is your callback policy if the repair doesn’t fix the problem?
- Do you offer a maintenance plan, and what does it include?
- How often should I replace my filter, and what type do you recommend?
- What can I do between visits to keep my system running well?
- Who should I call for after-hours emergencies?
Red Flags vs. Green Flags
| Red Flag | Green Flag |
|---|---|
| Phone diagnosis: tells you what’s wrong before inspecting the equipment in person | Refuses to guess over the phone and insists on an in-person inspection first |
| High-pressure replacement sales (“your system is dangerous and needs to go today”) | Gives you time to get a second opinion on any job over $3,000 |
| No license number or proof of insurance | Provides license number and certificate of insurance without being asked |
| Verbal-only or suspiciously low estimate | Detailed written estimate with parts, labor, and fees itemized |
| Recommends full replacement for a single-component failure on a system under 10 years old | Diagnoses and prices the specific failed component, then discusses your options |
| Suggests skipping permits on an installation | Pulls permits as standard practice and schedules inspections |
| Demands full payment before work begins | Asks for a 10-30% deposit with balance due on completion |
Money-Saving Tips
- Replace your air filter on schedule. A $10 filter swap every 60-90 days prevents hundreds of dollars in avoidable repairs. This is the single cheapest thing you can do for your HVAC system. Buy a multi-pack of MERV 11 filters so you always have replacements ready.
- Schedule service in spring or fall. HVAC companies are slammed in summer and winter. Off-season appointments often come with shorter wait times, lower prices, and better availability for the technician you actually want.
- Sign up for a maintenance plan, but do the math first. Plans run $150-$300/year and include two tune-ups, priority scheduling, and repair discounts. If you’d pay $200+ for two individual tune-ups anyway, the plan is a good deal. If not, skip it.
- Claim federal tax credits and manufacturer rebates. High-efficiency heat pumps and AC systems can qualify for $300-$2,000 in federal tax credits under the Inflation Reduction Act. Manufacturers also run seasonal rebates. Ask your tech about both before you sign anything.
- Don’t pay emergency rates for non-emergencies. Your AC running less efficiently in June isn’t a 2 a.m. emergency call. Schedule it for a weekday during business hours and save the 1.5x-2x after-hours premium for when you actually need it.
- Get three quotes and compare total cost, not just price. The cheapest quote that excludes permits, disposal, and a thermostat is more expensive than the mid-range quote that includes everything. Compare apples to apples.
Helpful Tools and Resources
A Wi-Fi thermostat learns your schedule and adjusts automatically, cutting energy costs 10% to 15%. It also makes it easy to spot system problems early because you can track runtime and temperatures remotely.
MERV 11 filters catch dust, pollen, and pet dander without restricting airflow. Buy a multi-pack and set a phone reminder to swap them every 60 to 90 days.
Seal small duct leaks in accessible areas like the attic or basement. Leaky ducts waste up to 30% of your conditioned air. Real aluminum foil tape (not cloth duct tape) is what the pros use.
- Energy Star HVAC Guide: Compare energy-efficient heating and cooling systems, find rebates in your area, and calculate potential energy savings based on your climate zone.
- NATE Certification Lookup: Verify whether your HVAC technician holds North American Technician Excellence certification. Search by name or company.
- Department of Energy - Homeowner’s Guide to HVAC: Covers system types, sizing, efficiency ratings, and maintenance basics. A solid starting point if you’re deciding between repair and replacement.
Next Steps
You’ve got the questions. Now get estimates from at least three companies, use this checklist during each conversation, and compare answers side by side. The right HVAC technician will welcome your questions, and the answers will speak for themselves.
If you’re working on other home projects, these guides can help:
- Questions to Ask Before Hiring a Plumber: covers licensing, pricing, and what to expect for common plumbing jobs.
- Questions to Ask Before Hiring an Electrician: essential questions for panel upgrades, rewiring, and more.
- Questions to Ask a General Contractor Before Hiring: everything you need for remodels, additions, and large projects.
Frequently Asked Questions
How much does it cost to hire an HVAC technician for a basic repair?
Most service calls run $75-$150 for the diagnostic visit, plus $150-$500 for common repairs like replacing a capacitor, contactor, or thermostat. Bigger repairs like compressor or evaporator coil replacement can range from $1,000-$3,000. Always get a written estimate before authorizing any work.
How do I know if my HVAC system needs to be replaced?
Consider replacement if your system is over 15 years old, uses R-22 refrigerant (phased out and expensive to refill), needs frequent repairs, or has a SEER rating below 13. The $5,000 rule is a useful gut check: multiply the repair cost by the system’s age. If the result exceeds $5,000, replacement usually makes more financial sense.
What is the difference between a heat pump and a furnace?
A furnace burns fuel, usually natural gas, to produce heat. A heat pump doesn’t burn anything. It moves heat from outdoor air into your home using electricity, and it reverses the process to cool in summer. Heat pumps are significantly more efficient in mild climates (above 30-35 degrees F). Furnaces still perform better in brutal winters. Many homeowners in moderate climates are switching to heat pumps for year-round efficiency, and federal tax credits are making that switch more affordable.
Should I get multiple quotes before hiring an HVAC technician?
Always. Get at least three written estimates for any job over $500. Compare not just the price but what each quote includes: equipment brand, SEER rating, warranty terms, labor coverage, and whether permits and disposal are included. Multiple quotes make outliers obvious in both directions.
When is the best time to replace an HVAC system?
Spring and fall, hands down. Demand is lower, so you’ll usually get shorter wait times and better pricing. Emergency replacements during a heat wave or polar vortex limit your ability to compare options, negotiate, or even think clearly. Planning ahead also gives you time to research rebates and tax credits that can offset $300-$2,000 of the cost.
Glossary
SEER Rating (Seasonal Energy Efficiency Ratio): A measure of how efficiently an air conditioner or heat pump cools over an entire season. Higher numbers mean less electricity used. The federal minimum in 2026 is SEER2 13.4-14.3 depending on your region. A jump from 14 to 20 SEER can cut cooling costs by 30% or more, but the upfront cost is significantly higher.
Refrigerant: The chemical compound that circulates through your HVAC system, absorbing and releasing heat to cool or warm your home. R-410A (Puron) is the current standard. R-22 (Freon) was phased out in 2020 and now costs $100-$200+ per pound to refill, which often makes replacement more cost-effective than repair.
Compressor: The heart of your air conditioning system. It pressurizes refrigerant and pumps it through the system. When the compressor fails, you’re usually looking at a $1,500-$3,000 repair, or a full system replacement if the unit is older. It’s the most expensive single component in your outdoor unit.
Heat Exchanger: The metal component inside your furnace that heats the air. Combustion gases pass through it, and your home’s air flows over the outside. A cracked heat exchanger is a serious safety hazard because it can leak carbon monoxide into your home. Replacement costs $1,500-$3,500, and on older furnaces, it’s often more cost-effective to replace the entire unit.
Manual J Load Calculation: The industry-standard method for determining the right size HVAC system for your home. It factors in square footage, insulation levels, window types and orientation, ceiling height, number of occupants, and local climate data. Any technician who sizes a new system without performing this calculation is guessing, and an incorrectly sized system wastes energy and money for its entire lifespan.