1. Are you licensed, insured, and EPA-certified?
The baseline. You want a licensed HVAC contractor with liability insurance, and a tech who's EPA 608-certified to legally handle refrigerant. Ask to see proof - a legitimate pro won't hesitate. Also ask: are you certified by the brand you're installing? Several manufacturers extend the warranty when a certified contractor does the work.
2. How did you size the system?
The answer you want is "a load calculation." Sizing by a rule of thumb or by matching the old unit leads to oversizing - the most common mistake, which causes short-cycling, poor dehumidification, and wasted money. If they didn't measure and calculate, that's a problem. Background: sizing guide.
3. What exactly is included in the quote?
Get it itemized: equipment, labor, the line set, electrical (dedicated circuit and disconnect), the mount or pad, permits, and startup/commissioning. This is how you compare bids fairly - a "cheaper" quote that excludes electrical or permits isn't actually cheaper. Know the real number first with the installation cost guide.
4. What's the warranty - on equipment and on labor?
Two separate warranties. The equipment warranty comes from the manufacturer (and is often longer when registered and installed by a certified contractor). The labor warranty comes from the installer - how long do they stand behind their work? Get both in writing, and confirm who registers the equipment.
5. What's your experience with ductless - and my brand?
Mini splits install differently from central systems. Ask how many they do a year and whether they've worked with your specific brand. Experience shows up in the details that determine whether the system lasts: how to find a good installer covers the full vetting process.
A few more worth asking
- Permits: will you pull the required permits? (Skipping them can bite you at resale.)
- Timeline: how long, and when can you start?
- Placement: where will the indoor and outdoor units go, and why? See where to put a mini split.
- Cleanup and walkthrough: will you show me how to run and maintain it?
The bottom line
Five questions - licensing/certification, sizing method, what's included, warranty (equipment and labor), and ductless experience - separate a pro from a gamble. Ask them of every bidder, get the answers in writing, and compare on value, not just price. Ready to line up quotes? Request them from local installers below, and check your target number with the cost estimator.
FAQ
What should I ask a mini split installer? Confirm licensing, insurance, and EPA/brand certification; how they sized the system (a load calculation); exactly what the quote includes; the equipment and labor warranties; and their ductless and brand-specific experience.
How do I compare mini split installation quotes? Get every quote itemized - equipment, labor, electrical, line set, permits - so you're comparing the same scope. A lower price that leaves out electrical or permits isn't really lower.
Should the installer do a load calculation? Yes. Proper sizing comes from a load calculation, not a rule of thumb. An installer who skips it risks oversizing the system, which hurts comfort and efficiency.
What warranty should a mini split installer offer? The manufacturer covers the equipment (often longer when registered by a certified installer); the installer should separately warranty their labor. Get both in writing.