Spring Startup Season Is Coming. Do You Know What 'Seasonal Variance' Actually Means?

We're eight weeks into Subpart C, and the first real-world test of the seasonal variance exemption is about to arrive. Across the country, commercial cooling systems that were pumped down or had charge pulled for the winter are about to come back online. Techs will be adding refrigerant. And the question is: do you need to run a leak rate calculation on that addition?

The answer is maybe — and the difference between "yes" and "no" comes down to four conditions that have to be true simultaneously.

If you missed the earlier posts in this series, start with the Subpart C field reference guide for a complete overview of every threshold and deadline. This post goes deep on the one exemption that matters most in March and April: seasonal variance.

The Definition

Subpart C defines seasonal variance in § 84.102 — in the same words the Section 608 rule uses at 40 CFR 82.152:

Seasonal variance means the removal of refrigerant from an appliance due to a change in ambient conditions caused by a change in season, followed by the subsequent addition of an amount that is less than or equal to the amount of refrigerant removed in the prior change in season, where both the removal and addition of refrigerant occurs within one consecutive 12-month period.

That's one sentence. Four distinct requirements. All four must be met for the exemption to apply.

The Four Conditions

Condition 1: Removal came first

Seasonal variance is not a blanket exemption for any refrigerant addition that happens to coincide with a change of season. It specifically requires that refrigerant was removed from the system first, then added back later.

The removal must have been a deliberate, documented act — pumping down a system for winter shutdown, recovering charge before mothballing seasonal equipment, or reducing charge in anticipation of lower ambient temperatures.

If no refrigerant was removed prior to the spring addition, the exemption does not apply. Period.

Condition 2: The removal was due to a change in season

The reason the refrigerant was removed matters. It must be because of a change in ambient conditions caused by a change in season. This typically means:

• Pumping down a rooftop unit before winter to prevent damage from low ambient temperatures
• Reducing charge on a chiller that will be idle during cold months
• Recovering refrigerant from seasonal cooling equipment that shuts down entirely in winter

What it does not cover: removing refrigerant for a repair, removing refrigerant because of a system malfunction, or recovering refrigerant for any reason unrelated to seasonal conditions. If the removal was for maintenance or repair, the subsequent addition is a normal service event and requires a leak rate calculation.

Condition 3: The amount added back is less than or equal to the amount removed

This is the condition most likely to trip contractors up. The math has to work.

In the third scenario, the system needed more refrigerant than was taken out. That extra 2 lbs represents refrigerant that leaked while the system was down, was lost during recovery, or is needed for some other reason. That additional charge does not qualify as seasonal variance — it's a standard refrigerant addition that triggers a leak rate calculation.

Condition 4: Both events occur within 12 consecutive months

The removal and the subsequent addition must both happen within one consecutive 12-month period. For most seasonal operations, this is straightforward: charge pulled in October or November gets added back in March or April. Well within 12 months.

But if a system sits idle for more than a year — say, charge was recovered in November 2025 but the system doesn't come back online until February 2027 — the 12-month window has closed and the exemption no longer applies.

What Seasonal Variance Is Not

This exemption generates more false confidence than any other provision in Subpart C. Here are the most common misapplications:

"It's spring, so any refrigerant I add is seasonal variance." No. Seasonal variance requires a prior documented removal. Topping off a system that ran low over winter is not seasonal variance — it's a standard addition that requires a leak rate calculation.

"The system always needs a charge in spring." That's not seasonal variance. That's a system with a chronic low-charge condition, possibly leaking. If no one deliberately removed refrigerant in the fall, the spring addition is a compliance event.

"We pump systems down every winter, but we don't track exact amounts." Then you can't prove the addition is less than or equal to the removal, and you can't claim the exemption. The regulation requires documentation of both the amount removed and the amount added.

"We recovered all the refrigerant before winter, so the spring recharge is obviously seasonal variance." Likely yes — but only if you documented the amount removed, the reason (change in season), the date, and the amount added back doesn't exceed what was taken out. Without records, it's your word against an auditor's checklist.

The Chronic Leaker Connection

A common worry: does the spring recharge count toward the 125% chronic-leaker figure? Read § 84.106(j) closely. The report is owed for an appliance "that leak[s] 125 percent or more of the full charge in a calendar year," and the report itself asks for the "annual percent refrigerant loss" (§ 84.106(m)(4)(v)). The test is refrigerant the appliance lost — EPA's preamble describes the threshold as a system having "to lose their full charge and then a significant quantity more" (89 FR 82682, Oct. 11, 2024).

A qualifying seasonal-variance addition replaces refrigerant that was deliberately recovered in the fall and stored. By definition it is less than or equal to the amount removed, so the appliance did not lose it. The rule does not mention seasonal variance inside paragraph (j) by name; the conclusion follows from the word leak. Ref LeakLog does not count a seasonal-variance addition toward the calendar-year 125% figure, for the same reason it does not run a leak-rate calculation on it.

What does count: every pound added beyond the amount removed. If you recovered 15 lbs and the system takes 17 lbs in March, the whole 17-lb addition falls outside the seasonal-variance definition (see the partial-exemption trap above) — it is a normal addition that triggers a leak-rate calculation, and it counts toward the calendar-year figure like any other addition.

Same system, same additions: 55% counted, not a chronic leaker. Had the March addition been 17 lbs against a 15-lb removal, the exemption would not apply and all 17 lbs would count — 28 lbs for the year, 140% of full charge, and a report due March 1, 2027.

Seasonal variance is not a get-out-of-compliance-free card. The fall removal and the spring addition both have to be documented — and every pound beyond what you took out is a leak that counts.

Spring Startup: A Documentation Checklist

If your shop does seasonal pumpdowns on commercial cooling equipment, here's exactly what you need to document to use the seasonal variance exemption correctly this spring.

At the time of fall removal (should already be done):

At the time of spring addition:

What you do NOT record for this event:

• A leak rate calculation (exempt)
• Days since last addition (not applicable)
• Whether a threshold was exceeded (not applicable)

What you DO still track:

• The amount added and the amount removed, per § 84.106(l)(12) (a qualifying seasonal addition is not counted toward the 125% chronic-leaker figure)
• All standard service documentation per § 84.106(l)(2)
• The date, because the next addition counts from it. The annualizing method's Step 2 in § 84.102 divides by "the number of days that have passed since the last day refrigerant was added." The rule does not say expressly whether an addition that was exempt from the calculation still counts as that day. Ref LeakLog takes the conservative reading: the spring recharge is the last day refrigerant was added, so a 5-lb top-off on a 100-lb system a month later annualizes over that month (58.9%), not over the whole winter since the last leak (15.2%). If you keep the log by hand, use the recharge date as the anchor for the same reason — a record that can produce the higher number can defend the lower one; the reverse is not true.

What If the Numbers Don't Match?

Real scenario: you recovered 12.4 lbs in November. In March, the system takes 14.0 lbs to reach full charge. (Worth noting that § 84.102's third determination method — actual measurements of refrigerant added or evacuated — explicitly contemplates seasonal variances, so these recover-and-recharge cycles are usable evidence of what the appliance actually holds.)

That 1.6 lbs difference means refrigerant was lost — either during recovery, from a slow leak over winter, or from some other cause. The system needs more than what was taken out.

Your options:

Option A: Charge to the removed amount only. Add 12.4 lbs (equal to the removal), claim seasonal variance, skip the leak rate calculation. Leave the system 1.6 lbs short. This is technically compliant for the seasonal variance exemption, but you're sending a unit out undercharged. Not recommended for system performance or customer satisfaction.

Option B: Charge to full and run the leak rate calculation. Add the full 14.0 lbs the system needs. This exceeds the removed amount, so seasonal variance doesn't apply. Calculate the leak rate on the full 14.0 lbs added. This is the cleaner path — you'll know whether the system is leaking, and you'll have a complete compliance record.

In most cases, Option B is the right call. If the system lost refrigerant over the winter, you want to know about it. Claiming a partial exemption while leaving a system undercharged is a short-term paperwork win that creates a long-term leak problem.

The Bottom Line for Spring 2026

This is the first spring under Subpart C. Every contractor who does seasonal pumpdowns on commercial cooling equipment is about to face this decision for the first time under the new rules.

If you documented your fall removals with exact pounds and seasonal reasoning — you're in great shape. Claim the exemption, add the charge back, document the match, and move on.

If you didn't document the fall removal — you can't claim the exemption this time. Run the leak rate calculation on the spring addition, treat it as a standard service event, and use this as the lesson to document every fall pumpdown going forward.

If the system needs more than you took out — don't force the exemption. Charge it properly, run the calculation, and find out whether you have a leak. That's the whole point of Subpart C.

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Next week: the reclaimed refrigerant standard that took effect January 1, 2026 — what the 15% virgin content cap means for contractors buying reclaimed refrigerant, and how to verify that your supply meets the new standard.