HVAC guide
10 Questions to Ask Before You Hire an HVAC Contractor
What to ask, what good answers sound like, and the red flags that should make you get another quote.
We're an independent guide, not a contractor. We may earn a fee if you request quotes through our partners.How we make money.
The short version
- Ask for proof of a license and insurance before anyone works on your home.
- A proper quote starts with a load calculation, not a guess based on your old unit.
- Get every quote in writing, with model numbers, and compare at least two or three.
- High-pressure 'today only' pricing is a red flag, not a deal.
A new heating or cooling system is one of the bigger purchases most homeowners make, and the quality of the installation matters as much as the brand of equipment. A well-installed mid-range system will usually outperform a premium system that was sized or installed poorly.
These questions help you separate careful contractors from the rest.
1. Are you licensed and insured?
Most states require HVAC contractors to hold a license, and many cities and counties add their own requirements. Ask for the license number and check it with your state’s licensing board. Also ask for proof of liability insurance and workers’ compensation, so you aren’t on the hook if someone is hurt on your property.
Red flag: vague answers, or “we work under someone else’s license.”
2. Will you do a load calculation?
The right size system depends on your home’s square footage, insulation, windows, ductwork, and climate. Contractors calculate this with a Manual J load calculation.
Good answer: “Yes, we’ll measure the house and run a load calculation.” Red flag: “Your old unit was 3 tons, so we’ll put in 3 tons.” The old unit may never have been sized correctly. An oversized system turns on and off too often, wears out faster, and leaves the house feeling clammy.
3. Will you look at my ductwork?
Leaky or undersized ducts can waste a large share of the heating and cooling you pay for. A good contractor checks the ducts and tells you whether they need sealing or changes, rather than connecting a new system to a problem.
4. What exactly is included in the quote?
Ask for a written quote that lists:
- The brand and model numbers of every piece of equipment (outdoor unit, indoor coil or air handler, furnace, thermostat)
- Removal and disposal of the old equipment
- New refrigerant lines, pad, electrical work, or drain lines if needed
- Permits and inspection
- Total price, payment schedule, and what deposit is required
Model numbers let you compare quotes fairly. Two “3-ton systems” can be very different.
5. What warranties come with it?
There are usually two kinds:
- Manufacturer warranty on parts. Many brands require the equipment to be registered within a set time after installation to get the full warranty. Ask whether the contractor registers it for you.
- Labor warranty from the contractor. This covers their workmanship. Ask how long it lasts and what it covers.
6. Will you pull a permit?
Replacing an HVAC system usually requires a permit and inspection. It protects you, because an inspector checks the work. A contractor who suggests skipping the permit to save money is cutting a corner you can’t see.
7. Are there rebates or tax credits I should know about?
Utility companies, states, and the federal government sometimes offer rebates or tax credits for efficient equipment. Programs change often, so ask the contractor which ones apply to the equipment they’re quoting, and confirm the details on the program’s official website before you count on the money.
8. Who will actually do the installation?
Ask whether the crew are employees or subcontractors, and who will be on site to answer questions. Either can be fine, but you should know who’s responsible.
9. How long will it take, and will I be without heat or air?
A straightforward replacement often takes a day. Ductwork changes or a new system type can take longer. Knowing this ahead of time matters in extreme weather.
10. Can I see reviews or talk to past customers?
Recent reviews from several sources give you a better picture than one testimonial on the contractor’s website. Look for how they handled problems, not just whether people were happy.
Red flags to watch for
- “This price is only good today.” Real pricing doesn’t expire in an hour.
- No home visit. A replacement quote given entirely over the phone skips the sizing and duct check.
- Pushing financing before discussing the system.
- A price far below the others. Ask what’s missing: permits, line sets, removal, or labor warranty.
- Asking for most of the money up front.
Bottom line
Take your time, get it in writing, and compare at least two or three quotes. If you’re still deciding whether you need a new system at all, read Repair or Replace? How to Decide When Your AC Breaks Down.