How to Choose an HVAC Contractor: 12 Questions to Ask

Equipment brand accounts for a small share of how your system performs. Installation quality accounts for most of it. Screen the installer harder than the box.

Studies of field-installed systems consistently find a large share operating well below rated efficiency because of charge errors, airflow problems and sizing mistakes. None of that is the manufacturer’s fault. Use these questions to separate crews.

The twelve questions

1. Will you perform a Manual J load calculation and give me the output? A no or a vague answer ends the conversation.
2. Will you measure static pressure in my existing ductwork? This is how they find out whether your ducts can support the new system.
3. Which exact indoor and outdoor models are you quoting, and are they an AHRI-matched pair?
4. Are you pulling a permit, and is inspection included? Skipping permits is a red flag for everything else.
5. How will you evacuate the line set, and to what micron level? The answer should mention a micron gauge and a target around 500 microns.
6. How do you verify the refrigerant charge? Weighing in charge and checking subcooling or superheat, not “by feel.”
7. What is the balance point of this design, and what backup heat will run below it?
8. Who registers the warranty and by when?
9. What is included in the labor warranty and for how long? One year is standard; two or more signals confidence.
10. Will the same crew that quoted the job perform it?
11. Can you provide three references from heat pump installs in the last year? Heat pump specifically, not air conditioning.
12. What happens if the system does not keep up on the coldest day? A confident designer has an answer.

Warning signs

• A quote produced in under fifteen minutes without entering the attic or crawl space
• Sizing based on the old unit’s capacity — which may itself have been wrong
• Pressure tactics tied to a discount that expires today
• Reluctance to put the scope in writing
• No mention of ductwork at all

Green flags

They ask about comfort complaints room by room. They look at your electrical panel unprompted. They explain a trade-off honestly rather than promising everything. They tell you something you did not want to hear.

Last checked August 2026. Prices are US ranges and vary by region — always confirm against written quotes.