COI, Additional Insured, and Waiver of Subrogation: What GCs Require From HVAC Subs

HVAC subcontractor insurance requirements come down to what a general contractor (GC) checks before you mobilize. They want a certificate of insurance (COI) showing your limits, additional insured (AI) endorsements naming the GC, and a waiver of subrogation on your general liability (GL) and workers compensation (WC). The certificate proves the coverage exists, but the endorsements attached to your policy are the coverage itself. Get the wording wrong and the GC's compliance software bounces your crew off the job before the first line set goes in.

What are the core HVAC subcontractor insurance requirements?

The core HVAC subcontractor insurance requirements are four policies and three endorsement types. GCs want a certificate showing general liability, workers compensation, commercial auto, and an umbrella above them. The subcontract then names the endorsements it demands: additional insured for ongoing and completed operations, primary and noncontributory, and a waiver of subrogation.

Commercial GCs treat $1M per occurrence and $2M aggregate as the floor for general liability coverage. Larger specs push it toward $2M/$4M. Commercial auto usually needs a $1M combined single limit. Umbrella demands land between $2M and $5M for a moderate-risk trade like HVAC (federal or infrastructure jobs often want $5M or more). On large projects the owner or GC may run a wrap-up program (OCIP or CCIP) that provides GL for every sub, changing what you carry on your own policy.

The table below maps each contract demand to the ISO or ACORD form that satisfies it, plus the document you actually hand the GC.

What a certificate of insurance actually proves

Every certificate of insurance HVAC subs send is evidence that policies existed on the day it was issued. It grants no coverage and changes no policy terms. The ACORD 25 form lists your carriers, limits, and effective dates on a single page. The GC's "certificate holder" line just means they were sent that proof.

Being named the certificate holder gives the GC a copy of the paperwork and nothing more. The actual rights come from the additional insured and waiver endorsements sitting on your policy, and that distinction is where subs get tripped up. Picture it this way: you send a clean ACORD 25, the GC's reviewer looks for the CG 20 37 behind it, finds nothing, and kicks the submission back. Most subs assume their agent already handled that step.

Additional insured for HVAC: ongoing and completed operations

An additional insured endorsement adds the GC, and often the property owner, to your general liability policy, so your coverage can defend them for claims arising from your work. The additional insured HVAC contractor language in a commercial subcontract almost always calls for two of these forms. One covers the GC while your crew is on site. The other covers them after the system is up and running.

Start with the CG 20 10, which handles ongoing operations: injury or damage that happens during installation. Completed operations is the other half of the exposure, and it kicks in once you demobilize. IRMI walks through how additional insured coverage splits along that ongoing-versus-completed line. The form that picks up those post-completion claims is the CG 20 37.

That second form earns its keep on HVAC work. Say a brazed joint fails or a flue vents wrong a year after signoff (both common, both expensive). Without the CG 20 37, the GC has no additional insured protection for that later claim. Many GCs now ask for a blanket version so one endorsement covers every job, and our explainer on blanket versus scheduled additional insured covers when each one fits.

Primary and noncontributory, plus waiver of subrogation

Primary and noncontributory (P&NC) means your policy pays first on a covered claim and doesn't ask the GC's insurer to chip in. A waiver of subrogation stops your carrier from later chasing the GC to recover what it paid out. Commercial subcontracts almost always require both, right alongside additional insured status.

The CG 20 01 endorsement handles the first, making your general liability primary and noncontributory so the GC's insurer is never billed ahead of yours. The waiver of subrogation HVAC subs carry then comes in two forms. On the GL side it's the CG 24 04, the endorsement IRMI describes for giving up your carrier's right of recovery. On workers comp it's the WC 00 03 13, which a carrier can issue as a blanket waiver when a contract calls for it.

Expect the WC waiver to cost a little extra, usually 5% to 10% of the manual premium. On a project carrying $20,000 of workers comp premium, you're looking at roughly $1,000 to $2,000, which most subs treat as a cost of bidding commercial work. Our guide to primary and noncontributory for HVAC breaks down the wording GCs enforce.

How to hand the GC a compliant insurance package

To clear a GC's insurance review, send the ACORD 25 certificate plus copies of every named endorsement, with the GC's exact legal name matching the subcontract. Order those endorsements the week you sign the subcontract, well ahead of the day you mobilize. Carriers take a few days to issue them. The certificate then has to match what's actually on the policy.

Underwriting adds the additional insured, P&NC, and waiver endorsements, and your broker generates the ACORD 25 with the endorsement copies attached. A broker who knows the trade reads the subcontract's insurance exhibit first. Then they order every form it names in one pass. Coverwatch assembles that endorsement stack from the contract language and issues compliant COIs for each GC an HVAC client signs with.

Getting the package right the first time keeps your crew on schedule and off the GC's non-compliance list. Coverwatch runs this review inside its flat-fee contractor insurance practice, and the wider renewal picture lives in our HVAC company insurance program guide.