Questions Worth Asking Before You Hire an HVAC Contractor
License, insurance, and eight questions that separate a contractor who measured your house from one who read a number off a chart.
By Chris Wheeler, Co-owner ·
We are writing this knowing it might cost us a job now and then, because a customer who asks these questions will occasionally decide somebody else answers them better. That is fine. We would rather compete on the answers.
The non negotiables
Are you licensed for this work in New Hampshire? Gas fitting and plumbing are licensed trades here, and the license is specific to the type of work. Ask what license the person doing your job holds, not just what the company has. You can verify a license with the state.
Are you insured, and can I see the certificate? You want general liability and workers compensation. Ask for a certificate of insurance sent directly from their carrier or agent, not a photocopy from a folder.
The workers compensation piece is the one people skip and it matters. If an uninsured worker is hurt in your basement, that can become your problem.
Will you pull the permit? Most equipment replacement requires one, and an inspection is a second set of eyes on the work at no cost to you. A contractor who suggests skipping the permit to save time is telling you something about how they work.
The ones that tell you whether they did the engineering
How did you determine the size? The answer you want involves a load calculation, and words like Manual J, or a description of measuring the house, counting and orienting windows, and looking at insulation.
The answer that should concern you is square footage times a rule of thumb, or matching the nameplate on the existing equipment. That old unit may well have been oversized, and matching it repeats somebody else’s mistake for another twenty years.
Can I see the load calculation? If they did one, they can show it to you.
What is this equipment’s capacity at our design temperature? For a heat pump especially. Rated capacity is measured at 47 degrees. What you care about is output near zero. A contractor who knows their product can pull up the extended capacity table.
What did you find when you looked at the ductwork? If they are quoting a ducted system and never went and looked at the duct, they have quoted a box, not a system. Undersized returns and leaky trunks will undermine any equipment you buy.
The ones about what happens after
What does commissioning include? Startup is not the same as commissioning. You want airflow measured, refrigerant charge verified by superheat or subcooling rather than by eye, static pressure measured, and controls configured. Ask for the numbers in writing when the job is done.
Who handles warranty registration? Most manufacturers require registration within a window, often 60 or 90 days, to get the full warranty term. Miss it and you drop to a much shorter base warranty. Some contractors handle it, some leave it to you and do not mention it. Find out which, and confirm afterward that it happened.
What is your labor warranty, separately from the parts warranty? These are different things. Parts come from the manufacturer. Labor comes from the contractor. A ten year parts warranty with one year of labor means year four’s compressor replacement is free on the part and not on the eight hours.
Who answers the phone at 9pm in January? Ask specifically what after hours coverage looks like and what it costs.
On comparing quotes
Get three, and make sure they are quoting comparable scope before you compare numbers. The cheapest quote is frequently cheapest because something is missing: the duct modifications, the electrical work, the permit, the removal and disposal of the old equipment, the condensate pump.
Ask each contractor to list what is included and what is excluded. Then compare like for like. A quote that is meaningfully lower than two others is usually explained by scope, not by generosity.
Also notice how the quote is presented. A single number on a page is hard to evaluate. A quote that itemizes the equipment with model numbers, the labor, the materials, the permit, and the exclusions is a contractor who is comfortable being examined.
The soft signals
Did they spend real time in the house, or did they walk through in ten minutes? Did they ask what rooms are uncomfortable and when? Did they look in the attic or the crawlspace? Did they ask about your fuel bills?
Did they tell you anything you did not want to hear? A contractor who says your attic insulation should come before the equipment, or that your existing unit has years left in it, is giving you information against their own short term interest. That is usually a good sign.
What we do
We will show you the load calculation. We will show you the capacity tables. We will give you a commissioning report with measured numbers. And if the honest answer is that you should fix something else first, or that a repair beats a replacement this year, we will say so.
If another contractor answers these questions better than we do, hire them. That is the point of the list.