Most people call the first number they find when the AC dies in July. That's how you end up with a roof ripped off and a bill you can't explain. Stop and do five minutes of homework first.
Licensing & Insurance Questions
Check if they're licensed for your state and city. Some places have separate mechanical permits. Ask for their license number and look it up yourself. Don't take their word for it. Insurance matters more. Demand proof of general liability and workers comp. If a tech gets hurt on your roof, that's your insurance paying unless they can prove theirs. Call the insurance agent to verify the policy is active, not just a piece of paper.
Experience & References Questions
Ask how long they've been doing residential work. Ten years in commercial doesn't mean they know your furnace. Get references from jobs like yours — same type of system, same house age. Call those references. Ask about cleanup, punctuality, and whether they stayed in budget. A company that hesitates to give references has a reason.
Pricing & Timeline Questions
Get a written quote before work starts. Don't accept a verbal estimate over the phone. A real quote breaks down parts, labor, taxes, permits. Ask what happens if the job takes longer than they said. Will they eat the extra hours or bill you? Also ask about payment schedule. Never pay the full amount upfront. A deposit is normal, but the rest is due on completion, not when they pull into the driveway.
Contract Questions
Read the whole contract before signing. Look for vague phrases like "best efforts" or "as needed" — those mean they can do whatever they want. Make sure the contract lists the exact equipment model numbers, not just "new AC unit." Include the start and end dates, but leave a buffer. Also get the warranty terms in writing, both manufacturer and labor. If the contract is missing something, walk away.
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