Is Your Rooftop Unit Covered? Where Packaged RTUs, Commercial Splits, and Heat Pumps Cross the 15-Pound Line

No piece of equipment shows up on a small commercial contractor's schedule more often than the packaged rooftop unit. The strip mall has six of them. The dental office has two. The restaurant has one over the dining room and a walk-in below it in the kitchen. If your shop runs commercial maintenance agreements, RTUs are the book of business.

So it matters that when the EPA wrote the definition that carries Subpart C's tightest leak-rate threshold, it didn't describe rooftop units in general terms. It named them.

Since January 1, 2026, 40 CFR Part 84, Subpart C has applied federal leak-rate math, a 30-day repair clock, and a three-year records file to covered appliances — and whether a specific rooftop unit is covered comes down to a test most people quote wrong. It is not the tonnage. It is not the building. It is the full charge, judged one refrigerant circuit at a time.

Here's how to read the line for the equipment you service every day.

The Three-Part Test, Applied to a Roof

§ 84.106(a) makes the leak-repair rules apply to "refrigerant-containing appliances with a full charge of 15 or more pounds of refrigerant" where the refrigerant is a regulated substance or a substitute "that has a global warming potential greater than 53." Three questions, in order:

1. Does the refrigerant clear GWP 53? For rooftop equipment, almost always yes. R-410A — still the refrigerant in the overwhelming majority of installed RTUs — has a GWP of 2,088. And don't let the new equipment fool you: R-454B, the low-GWP successor shipping in new packaged units, sits at 465. That's low enough for the Technology Transitions manufacturing rules, and 35 times too high for the Subpart C exemption. A brand-new R-454B rooftop unit takes the same leak-rate math as the R-410A unit it replaced. R-32 (GWP 675) clears the bar too.

2. Is the appliance exempt as residential or light commercial? § 84.106(a)(3)(ii) removes "refrigerant-containing appliances used for the residential and light commercial air conditioning and heat pump subsector" — the carve-out that takes houses, window units, and the single small unit on a one-suite office out of the rule entirely. Where exactly that subsector ends is its own question, and we've mapped it in detail — but the short version for this post is that the multi-unit commercial roof doesn't get the exemption. The RTUs over a strip mall, a school, a medical office, or a restaurant are commercial comfort cooling, full stop.

3. Is the full charge 15 pounds or more? This is the question that actually decides coverage for rooftop equipment — and the rest of this post is about answering it correctly.

One more thing before we get there: which category a covered RTU lands in. § 84.102 defines comfort cooling with a named list:

"Packaged roof-top units." "Commercial split systems." "Dual-function heat pumps." The definition reads like a list of what's on your truck schedule this week. And comfort cooling carries the 10% leak-rate threshold under § 84.106(c)(2)(iii) — the strictest of the three, tighter than the 20% a supermarket rack gets. If you're not sure why the category question matters or where the odd cases land, the category post walks all three § 84.102 definitions verbatim; the one-line answer for this post is: a covered RTU is judged at 10%.

"How Much Refrigerant Is in a 5-Ton Rooftop Unit?"

Contractors ask this question because the coverage line is written in pounds and the equipment is sold in tons. The honest answer: the rule doesn't care what's typical — it cares what's on the nameplate. § 84.102 defines the number that decides everything:

For a packaged rooftop unit, method 1 is usually sitting right there: the factory charge on the data plate. That's the appliance the manufacturer built, charged, and shipped as a sealed system — no field-installed line set to add refrigerant nobody counted. For a commercial split system, method 2 earns its keep, because the nameplate charge assumes a nominal line set and the real one on the building may be sixty feet longer.

As a loose field observation — not a rule, and not the test — packaged R-410A equipment tends to carry a few pounds of refrigerant per ton of cooling, which is exactly why the small end of the commercial range is where coverage gets decided unit by unit. A 3- or 4-ton packaged unit usually sits under 15 pounds. A 5-ton can land on either side of the line depending on the design generation and coil type. By 7.5 tons, most single-circuit packaged units are over it. But two units of the same nominal tonnage from different manufacturers — or different decades — can fall on opposite sides. The tonnage gets you a guess. The nameplate gets you a record.

And a record is what the rule actually demands. Under § 84.106(l)(1), owners and operators were required to determine the full charge of every appliance with 15 or more pounds by January 1, 2026 — or at installation for anything newer — and keep, for each one, the owner's identity, the address, the full charge and the method used to determine it, any revisions with dates, and the installation date, until three years after the appliance is retired. If you used method 4's established range, the range, its midpoint, and how you derived it go in the file too. The full-charge post digs into all four methods and their tradeoffs — what matters here is that "I think it's about 12 pounds" is not a determination. A nameplate photo attached to the equipment record is.

The Dual-Circuit Wrinkle Most People Miss

Here's the sentence in § 84.102 that changes the answer for a lot of mid-size rooftop equipment, from the definition of "refrigerant-containing appliance":

Larger packaged RTUs — commonly starting in the 7.5-to-12.5-ton range — are frequently built with two independent refrigerant circuits, each with its own compressor, coil sections, and metering device. Under Subpart C, that cabinet on the roof is not one appliance. It's two.

Run the numbers on what that means. A 10-ton dual-circuit unit whose nameplate shows two independent circuits at 13 pounds each is two 13-pound appliances — neither covered, even though there are 26 pounds of R-410A in the cabinet. The single-circuit unit next to it with a 16-pound charge is covered. Coverage on a mid-size commercial roof isn't decided cabinet by cabinet; it's decided circuit by circuit, off the per-circuit charges the data plate lists separately.

Three cautions before you clear half a roof with this rule:

• The circuits have to be independent. Two compressors feeding a shared circuit — a tandem set — is one appliance. The test is whether the refrigerant circuits are sealed off from each other, and the nameplate's per-circuit charge listing is your first evidence.
• Document the determination either way. If your compliance position is "this 26-pound cabinet is two 13-pound appliances," the (l)(1) file should show per-circuit full charges and the method. An inspector reading a bare "26 lb" on a service ticket will draw the other conclusion.
• It cuts both ways as equipment ages. Replace a dual-circuit unit with a modern single-circuit design of the same tonnage and a roof that had no covered appliances may suddenly have one.

Covered Day One: What Actually Changes

Say the nameplate settles it — the 7.5-ton unit over the office suite carries an 18-pound charge, single circuit. It's a covered comfort cooling appliance. What does that mean in practice?

It means § 84.106(b) is now live on that unit: the owner or operator "must calculate the leak rate every time refrigerant is added to an appliance," with narrow exceptions for additions right after a retrofit, a new installation, or a qualifying seasonal variance. Whether the routine top-off triggers the math — it does — is its own post. And on a comfort cooling appliance, the number the calculation gets judged against is 10%.

On an 18-pound charge, 10% is not much refrigerant:

Run those through the annualizing method and the pattern is obvious. The first calculation after January 1, 2026 substitutes 365 days, so 3 pounds into 18 annualizes to 16.7% — over the threshold on the very first service call. A pound and a half into the same unit stays under at 8.3% (and goes in the record anyway). And the mid-season repeat customer is worse than it looks: 2 pounds into a 24-pound unit only 90 days after the last addition annualizes to 33.8%, because the method scales a 90-day loss to a full year. Small charges make the 10% threshold easy to trip — that's the defining compliance fact of rooftop equipment. Check your own numbers against the R-410A calculator — or the R-454B calculator for the new equipment — before an inspector does.

When a calculation does come back over 10%, the § 84.106(d) clock starts: leaks identified and repaired within 30 days of the addition, followed by verification testing, with the deadline math running from the service date — not from when the paperwork got around to noticing. After an exceedance, comfort cooling appliances also pick up an ongoing inspection duty — annual, at any charge size, rather than the quarterly schedule the big refrigeration racks get.

The Roof Inventory Worth Doing This Week

If you maintain commercial accounts, the applicability work for rooftop equipment is one visit per roof:

1. Photograph every nameplate. Unit by unit: model, serial, refrigerant, factory charge — per circuit, where circuits are listed separately.
2. Mark the line. Each independent circuit at 15+ pounds is a covered appliance; log its full charge and the method ((l)(1) wants both). Circuits under 15 pounds go in the file too, with the determination that puts them under — that record is what makes "not covered" a position instead of a guess.
3. Flag the split systems. Field-installed line sets mean the nameplate alone may understate the real charge; a method-2 calculation or method-3 measurement settles it.
4. Tell the building owner which is which. The duty to calculate leak rates and repair on deadline sits with the appliance's owner or operator — your customer — and the contractor who can say "three of your six units are federal, and here's the file" is the contractor who owns that conversation.

The rooftop unit went from invisible-to-regulators to named-in-the-definition in one rulemaking. The good news is that the coverage question resolves to numbers you can read off a data plate in an afternoon — and once it's determined, recorded, and filed, it's determined for the life of the unit.