Most heat pump red-flag advice repeats itself. Brand with no model number. Tonnage with no Manual J. Backup heat with no price. An expired tax credit still on the page. Those are real, and this site's own buying guide, sizing guide, and real cost guide already cover them in detail. Repeating them here would not tell you anything new.
Three things get skipped almost everywhere: what a commissioned system's numbers should actually say on paper, whether the contractor is licensed and insured to do the work in your specific state, and what happens to your warranty and your service options if that company is gone in three years. This page is scoped to those three.
The three gaps a checklist alone doesn't close
| Gap | What it protects against | Where the answer lives |
|---|
| Commissioning evidence | A system that runs but never delivers its rated capacity, wastes energy, or fails early because charge, airflow, or evacuation were never verified | Below, "Commissioning evidence" |
| License and insurance | Unlicensed work, an uninsured crew on your property, or no legal recourse if something goes wrong | Below, "License and insurance verification" |
| Service continuity | A warranty you can't use, or a system only one contractor can service, after the installer is unreachable | Below, "Service risk" |
Commissioning evidence: the numbers that should exist on paper
A red flag list tells you to "ask about commissioning." It rarely tells you what a real answer sounds like. These are the checks that have an actual number or certification behind them, not just a promise.
| Check | What to ask for | Why it's verifiable |
|---|
| Refrigerant-circuit certification | The technician's EPA Section 608 certification type (Type II or Universal covers the high-pressure refrigerants, R-410A, R-32, and R-454B, used in residential heat pumps) | Federally required to open a sealed refrigerant circuit at all; credentials don't expire, so a real tech can name the type without hesitating |
| Evacuation | The vacuum reading pulled before charging, in microns | Manufacturer installation manuals for Daikin, Carrier, and Century split heat pumps independently specify evacuating to 500 microns or below, then holding vacuum and confirming it doesn't rise past roughly 1,000 microns as a leak check, before any refrigerant goes in |
| Refrigerant charge | Whether the system uses superheat or subcooling to verify charge, and against what target | Fixed-orifice and piston metering devices are checked by superheat; TXV-metered systems are checked by subcooling. Using the wrong method for the metering device is a common shortcut, and a contractor who can't say which method they used on your equipment likely charged by pressure and feel, not by measurement |
| Airflow | What reference they verified airflow against | ACCA's own guidance is explicit that there is no single "400 CFM per ton" number: humidity, elevation, and air density change the correct target, so airflow should be checked against the equipment manufacturer's own tables, not a rule of thumb |
| Static pressure (ducted systems only) | A measured total external static pressure (TESP) reading against the equipment's rated maximum | Already covered in detail, with the exact test and threshold, in ducted vs mini-split |
| Defrost cycle | Confirmation the defrost cycle was tested or demonstrated, not just assumed to work | A five-minute check most technicians can force manually; skipping it is how "my heat pump won't stop defrosting" complaints start showing up in year one |
| Balance point and lockout settings | The outdoor temperature where backup heat is expected to engage, and why | This site's own worked balance-point method, with a 57-metro design-temperature lookup, is in verify heat pump output at design temperature |
None of these require you to own test equipment. They require the contractor to have used it and to be willing to tell you the number, not just the outcome. "It's running fine" is not an answer to "what did the vacuum gauge read."
License and insurance verification, by state
Licensing structure varies more than most buyers expect, and none of this site's five priority markets handle it the same way. Check the actual rule for your state before assuming a "license number" on a quote means what you think it means.
| State | How HVAC work is licensed | How to verify |
|---|
| Massachusetts | No single statewide HVAC contractor license. Refrigeration licenses apply only to systems over 10 tons, which residential heat pumps are not. The relevant checks are the contractor's Home Improvement Contractor (HIC) registration and, for the electrical scope, a licensed electrician | Mass.gov: Check an Occupational Board license, Massachusetts HIC License Lookup |
| Maine | No separate state HVAC or mechanical license specific to heat pumps. The electrical portion must be done by a licensed electrician (or, under a specific board agreement, a licensed oil-burner technician). Efficiency Maine's own Registered Vendor program requires EPA 608 Type II or Universal certification plus ENERGY STAR manufacturer installer training, which makes its vendor list a practical stand-in for a license check | Efficiency Maine: Find a Registered Vendor |
| New York | No statewide HVAC contractor license. Licensing and registration are set city by city and county by county; NYC, Buffalo, Rochester, Albany, and Yonkers each run their own rules, and many upstate counties require only a building permit. EPA 608 certification is required everywhere in the state regardless of local licensing | Check your specific city or county building department; there is no single state portal |
| Connecticut | State-licensed. The S-1 Unlimited Heating, Piping, and Cooling Contractor license (or a matching S-2) covers HVAC work under Connecticut General Statutes 20-330, issued by the Department of Consumer Protection | Connecticut DCP: Verify a License |
| California | State-licensed. A C-20 Warm-Air Heating, Ventilating and Air-Conditioning contractor license is required through the Contractors State License Board. C-20 holders carry a $25,000 contractor bond, and any contractor with employees must carry workers' compensation | CSLB License Lookup |
Whatever your state requires, get a certificate of insurance (COI), not just a verbal "we're insured." A COI worth trusting names the contractor as the insured party exactly as licensed, shows active workers' compensation, and carries general liability limits in the range of $1 million per occurrence and $2 million aggregate for residential HVAC work, which is typical for the trade. A COI is a snapshot: call the insurance producer listed on it to confirm the policy is still active before the crew arrives, not after.
Service risk: what happens after the truck leaves
Two things matter here that a red-flag checklist rarely raises.
Communicating, brand-locked controls. Systems sold with a proprietary communicating thermostat, such as Mitsubishi's kumo cloud or Daikin's One+, route diagnostics and, in some cases, service requests through that manufacturer's own ecosystem. Mitsubishi's kumo connect feature, for example, is explicitly limited to its own designated Diamond Contractors and Ductless Pros. That is not a reason to avoid a communicating system, but it means your practical service options may be narrower than a generic thermostat would allow. Ask who else in your area can service this exact control setup before you need it serviced.
What survives if the installer closes. As explained in the warranty guide, a heat pump carries two separate warranties: the manufacturer's parts warranty, which stays with the registered equipment, and the installer's labor warranty, which is a promise from that specific company. If the manufacturer warranty was properly registered, it generally isn't voided by the installer going out of business. The labor warranty is a different story: it is a contract with a company that may no longer exist, and there is typically no other party obligated to honor it unless your state's contractor bond or a home-improvement guaranty fund covers unfinished work. Ask directly what happens to your labor warranty if the company closes, and confirm whether your state's licensing program includes a bond or guaranty fund you could file against. This is one more reason the license and insurance check above isn't optional paperwork: an unlicensed or bond-free installer leaves you with no fallback at all.
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Good answer vs bad answer
| You ask | Bad answer | Good answer |
|---|
| "What did the vacuum reading say before you charged the system?" | "It's fine, we always pull a good vacuum" | A specific micron number, at or below 500, with a stated hold/decay check |
| "Superheat or subcooling, and what's the target?" | "We charge by feel" or a shrug | Names the metering device type and the number they charged to |
| "What airflow reference did you use?" | "400 CFM per ton, that's standard" | Names the OEM's airflow table for the exact model installed |
| "What's your license number and can I verify it?" | A number with no state portal to check it against, or "we don't need one for this" | A number you can independently confirm on your state's own lookup tool |
| "What happens to my labor warranty if you close?" | No answer, or "that won't happen" | An honest answer, plus confirmation of bonding or guaranty-fund coverage |
What we could not verify
No source found gives a single universal micron target, a fixed CFM-per-ton number, or a fixed lockout-temperature offset; the sourced manufacturer and ACCA material is explicit that these are checked against equipment-specific tables, not a fixed rule, and this page states the same rather than inventing round numbers. There is no independently verified legal guarantee that a manufacturer warranty always survives a contractor's closure or that a labor warranty always dies with it; confirm both the registration status and your state's specific bond or guaranty-fund rules rather than assuming either outcome. Pricing for a third-party commissioning re-check is not covered here because it varies too widely by market to publish a defensible range.
Frequently Asked Questions
What certification does a heat pump installer need to handle refrigerant?
At minimum, EPA Section 608 Type II certification, which covers the high-pressure refrigerants (R-410A, R-32, R-454B) used in residential heat pumps; Universal certification also covers it. This is a federal requirement for anyone opening a sealed refrigerant circuit, regardless of state licensing rules, and the credential doesn't expire.
How do I check if my heat pump contractor is actually licensed?
It depends on your state. Massachusetts and Maine don't issue a single statewide HVAC license, so check Home Improvement Contractor registration (Massachusetts) or the Efficiency Maine Registered Vendor list (Maine) instead. New York licenses at the city or county level with no single state portal. Connecticut and California both issue a state HVAC contractor license (S-1 in Connecticut, C-20 in California) with a free online lookup. See the table above for the direct link for your state.
What happens to my heat pump warranty if the installer goes out of business?
The manufacturer's parts warranty, if it was registered on time, generally stays with the equipment regardless of what happens to the installer. The installer's own labor warranty is a separate promise from that specific company, and it commonly ends if the company closes, unless your state's contractor bond or a guaranty fund covers unfinished warranty work. Ask about this before signing, not after.
Does a communicating thermostat lock me into one contractor?
Not entirely, but it can narrow your options. Brand-proprietary communicating controls like Mitsubishi's kumo cloud or Daikin's One+ route diagnostics through that manufacturer's ecosystem, and some manufacturer service features are restricted to that brand's own certified-contractor network. Ask who else locally can service the exact control setup you're being quoted before you need a second opinion.
What number should a heat pump be evacuated to before charging?
Manufacturer installation manuals across multiple brands specify evacuating to 500 microns or below, then holding vacuum to confirm it doesn't rise significantly, as a leak check, before refrigerant is added. If your contractor can't tell you the number they pulled, ask them to check next time and put it in the paperwork.
Sources
