Spring Startup Season Is Coming. Do You Know What 'Seasonal Variance' Actually Means?
Subpart C lets you skip the leak rate calculation when adding refrigerant back after a seasonal removal. But four conditions must be met — and most contractors are getting at least one of them wrong.
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 borrows the seasonal variance definition from Section 608 (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.
| Fall Removal | Spring Addition | Seasonal Variance? |
|---|---|---|
| Recovered 8 lbs in November | Added 8 lbs in March | Yes — equal to amount removed |
| Recovered 8 lbs in November | Added 6 lbs in March | Yes — less than amount removed |
| Recovered 8 lbs in November | Added 10 lbs in March | No — exceeds amount removed |
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.
If you removed 8 lbs and need to add 10 lbs, you cannot claim seasonal variance on the first 8 lbs and then calculate a leak rate on the remaining 2 lbs. The regulation defines seasonal variance as a single addition that is less than or equal to the amount removed. The moment the total addition exceeds the removal, the exemption does not apply to that service event — and you calculate the leak rate on the full amount added.
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.
Section 84.106(l)(12) is explicit: owners or operators using the seasonal variance flexibility must maintain records stating they are using it and documenting the amount added and removed. If your fall pumpdown wasn't documented with exact pounds recovered and the reason noted as seasonal, you've already lost the exemption before spring arrives.
The Chronic Leaker Connection
Here's the detail that catches even careful contractors off guard: seasonal variance exempts you from the leak rate calculation — it does not exempt the refrigerant addition from the chronic leaker total.
Recall from Post 7 that the chronic leaker formula is simple: total pounds added in the calendar year divided by full charge. If that number hits 125%, the system is a chronic leaker and must be reported to the EPA by March 1 of the following year.
The regulation does not exclude seasonal variance additions from this calendar-year total. So if you recover 15 lbs from a 20-lb system in November and add 15 lbs back in March, you've added 15 lbs in that calendar year. That's 75% of full charge from a single seasonal addition — before any leaks are even factored in.
| Event | Lbs Added | Cumulative Calendar Year | % of Full Charge (20 lbs) |
|---|---|---|---|
| March — seasonal recharge | 15.0 | 15.0 | 75% |
| June — service call, added 2.5 lbs | 2.5 | 17.5 | 87.5% |
| September — service call, added 4.0 lbs | 4.0 | 21.5 | 107.5% |
| November — service call, added 4.5 lbs | 4.5 | 26.0 | 130% → Chronic leaker |
That system hit 130% — and three-quarters of the total came from the seasonal recharge. The seasonal variance exemption saved you from running a leak rate calculation in March, but it didn't protect the system from chronic leaker status.
Seasonal variance is a leak rate calculation exemption. It is not a get-out-of-compliance-free card. The refrigerant still went into the system, and the EPA still counts it.
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):
| Document | Example |
|---|---|
| Equipment ID and location | RTU-2, north wing, 200 Commerce Dr |
| Date of removal | November 3, 2025 |
| Reason for removal | Seasonal shutdown due to change in ambient conditions |
| Refrigerant type | R-410A |
| Amount removed (exact lbs) | 12.4 lbs |
| Full charge of system | 18.0 lbs |
| Technician name and cert # | M. Torres, EPA 608 Universal |
| Method of recovery | Recovered to tank, weighed |
| Notation | "Seasonal variance — fall pumpdown" |
At the time of spring addition:
| Document | Example |
|---|---|
| Equipment ID and location | RTU-2, north wing, 200 Commerce Dr |
| Date of addition | March 12, 2026 |
| Refrigerant type | R-410A |
| Amount added (exact lbs) | 12.4 lbs |
| Amount removed in prior seasonal event | 12.4 lbs (November 3, 2025) |
| Confirmation: added ≤ removed | Yes — 12.4 ≤ 12.4 |
| Within 12-month window | Yes — 4 months between events |
| Notation | "Seasonal variance — spring recharge, exempt from leak rate calculation per § 84.106(b)" |
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, for the chronic leaker calendar-year total
- All standard service documentation per § 84.106(l)(2)
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.
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 single best practice for seasonal variance documentation is to weigh the refrigerant on recovery in the fall and weigh it again on recharge in the spring. If the tank weighs less than expected, you know refrigerant was lost — either during recovery or from the tank itself. That difference is important data, even if it means you can't claim the exemption.
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.
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.
Seasonal Variance Tracking, Built In
Ref LeakLog links fall removals to spring additions automatically. When the amounts match, the exemption is applied and documented. When they don't, the leak rate calculation runs instantly. No guesswork, no missed records.
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