Questions to ask any contractor.

Most homeowners feel they cannot push back on an HVAC estimate because they do not know the vocabulary. In practice the opposite is true. The best questions are simple, and they do not require you to evaluate the answer on the spot. They require the contractor to be specific, and specificity is what you are actually shopping for.

Here is the full set, organized by what you are trying to learn.

Before you call

Have the estimate in front of you and a pen. Write the answers on the page itself, so that when you compare two estimates a week later, the answers travel with the document rather than living in your memory.

Ask for anything material in writing, by email. Not because you expect a problem, but because an installation happens weeks after the conversation, sometimes with a crew who was not on the call.

About the equipment

What are the full model numbers of the furnace, the outdoor unit, and the indoor coil? Everything else on the page depends on these. If an estimate has no model numbers, nothing on it can be verified.

Is this single-stage, two-stage, or variable equipment, and why that choice for my house? The “why” is the useful half. A contractor who says “two-stage, because your second floor runs warm and longer cycles will even that out” has been paying attention to your house.

What is the AFUE and the SEER2? Ask specifically for SEER2, not SEER, so two estimates end up on the same scale.

Are the outdoor unit and indoor coil a matched, rated pair? The efficiency figure only holds for the pair that was tested together.

Did the size come from a load calculation, or from the equipment being replaced? Both answers are common. You are not accusing anyone. You are finding out whether your window replacement and attic insulation were accounted for.

About the installation

Does this include any duct modifications? Then the follow-up that matters: what happens if more are needed once you open it up? You want a range, or at least a stated hourly rate, rather than discovering it on installation day.

Is any electrical work included, and does my panel have capacity? Panels in homes built before the war are frequently full. Somebody has to handle that, and it belongs on the page.

How is the new furnace vented, and does that change how my water heater vents? If the furnace is coming off a shared chimney, the water heater is now alone in a flue sized for two appliances.

Where does the condensate go? A floor drain is cheap. A pump or a long run through finished space is not.

Is the line set being replaced, flushed, or reused? A silent page has made this decision for you.

How many installers, and how many days? This is the fastest way to sanity-check a cheap estimate against an expensive one with the same written scope.

Does this job need a Village permit, who pulls it, and is the fee included? The Village’s permit sheet lists like-kind replacement as not needing one. New equipment, new central air, a fuel or venting change, a relocation or new piping does. The Village’s express-permit page also lists furnaces and air conditioners, so confirm with Building & Zoning at (708) 714-3552 before work starts.

What do you do about the mess? Floor protection, the wall penetration where the new vent goes through, and hauling the old system out. In a house with a narrow turn-around stairwell, the last one is not trivial.

About the warranty

What is the parts warranty on each major component? A headline number often applies only to the heat exchanger.

Who registers the equipment, and when will I get confirmation? The extended parts term usually requires registration inside sixty or ninety days. Unregistered, it can drop by half.

What is the labor warranty, in years? Ask for this as its own number. It is not the same promise as the parts term and it does not come from the same company.

Does the labor warranty cover diagnostic time? Diagnostic time is the item most commonly excluded.

Is the parts warranty transferable if I sell? Worth something at closing, and usually requires a filing within a short window.

About price and terms

What is the installed cash price? Ask for it explicitly, especially if you have been quoted a monthly payment. Promotional financing sometimes carries a dealer fee folded into the installed cost.

How long does this price hold?

What deposit is required, and what is the payment schedule?

Which rebates or incentives are you applying, is the price before or after them, and who files the paperwork? These change frequently and depend on the specific equipment.

Which of these accessories could come off without affecting the system? A useful question when a filter cabinet, humidifier, surge protector, and UV lamp have all appeared on a page you did not ask for them on.

About the company

Are you licensed and insured, and can I see the certificate? Ask, and expect a straightforward yes with paperwork attached.

Who will actually be in my house, your employees or a subcontracted crew? Either can be fine. You just want to know.

Who do I call if something goes wrong in February at nine at night?

Will you come back if the second floor still runs warm? An honest answer distinguishes between a system problem and a distribution problem, and says what is included in fixing each.

What good answers sound like

You are not grading the technical content. You are listening for three things.

Specificity. Model numbers, not brand names. Years, not “a long warranty.” A number, not “we will take care of you.”

Willingness to say what they do not know. “I will not know about the return duct until we pull the old furnace, and here is what it costs if it needs resizing” is a better answer than false certainty.

Patience. You are spending five figures on your house. A contractor who is annoyed by nine questions at the estimate stage will not be easier to deal with during an installation.

Conversely, the pressure signals are worth naming: a discount that expires tonight, a strong push toward financing before you have the cash price, a refusal to put the scope in writing, or a diagnosis of a system that has not been examined.

The short list

If you only get one phone call, ask these nine.

• What are the full model numbers of the furnace, condenser, and indoor coil?
• Did the size come from a load calculation, or from the existing equipment?
• Is this single-stage, two-stage, or variable, and why that for my house?
• Does the installation include duct modifications, and what if more are needed?
• Is electrical work included, and does my panel have capacity?
• How is it vented, and does that change how my water heater vents?
• What is the labor warranty, in years, and does it cover diagnostics?
• Who registers the parts warranty, and when do I get confirmation?
• What is the installed cash price, and how long does it hold?

Write the answers on the estimate. Then do the same with the second estimate, and the comparison will mostly make itself.

Whether your house is near Willard or a few blocks off Madison, the questions do not change. And you can still make dinner from Bertolli’s before the second contractor calls back.