Key Facts: Portable Air Conditioner BTU Ratings
This page is SACC Decoded's maintained fact reference — the rating and test-procedure facts our comparisons are built on, restated in plain prose. We report disclosed figures and clearly-labeled derived calculations, never a test result of our own.
Why there are two BTU numbers
A portable air conditioner's box usually shows an ASHRAE-128 BTU rating, a laboratory test originally built for window units. Since a 2016 DOE test-procedure final rule (effective for compliance starting the 2019 model year), portable units must also disclose a SACC (Seasonally Adjusted Cooling Capacity) rating, which factors in exhaust-duct heat leakage, infiltration of outside air pulled in to replace what's exhausted, and the unit's own motor heat. The SACC number is typically 15-50% lower than the advertised ASHRAE figure for the same unit. Full explainer: Why Does My Portable AC Have Two BTU Ratings?
What SACC actually tests
SACC is not a marketing term — it is the specific DOE test metric defined for portable air conditioners because the older ASHRAE test overstated real-world performance. It accounts for three things a plain BTU rating ignores: duct/hose heat leakage, air infiltration, and cycling losses. See What Is SACC Rating?
Is disclosure actually required?
Yes, since the DOE's test procedure and FTC EnergyGuide labeling requirements took effect for compliance starting with 2019-model-year units, SACC must be disclosed alongside the ASHRAE figure. In practice, we still find budget and newer-import listings that show only an unlabeled BTU number with no SACC figure anywhere on the page — see Is SACC Disclosure Required? and our SACC Reality Index dataset, which flags every case where SACC was not found.
Single-hose vs dual-hose
A single-hose unit exhausts hot air through one hose, pulling the room into negative pressure and drawing warm, humid outside air in through gaps to replace it. A dual-hose unit uses a second hose to draw intake air from outside instead of the room, reducing (not eliminating) that infiltration effect — dual-hose units tend to hold their SACC-rated output more consistently as outdoor temperature rises. Full comparison: Single-Hose vs Dual-Hose Portable AC.
Sizing by SACC, not the box number
Room-coverage claims should be built on the maker's SACC-based square-footage figure, not the bigger ASHRAE-based number, and assume a standard ~8-foot ceiling with normal insulation. High ceilings, large windows, direct sun, or an open floor plan all reduce real coverage below the advertised figure. See What Size Portable AC Do I Actually Need?.
The gap percentage is a derived calculation
Every "gap percentage" figure on this site is calculated by us as (advertised BTU minus disclosed SACC BTU) divided by advertised BTU, using only the two figures each manufacturer already published. We are not accusing any brand of misrepresentation — both numbers are legitimate results of two different, DOE-defined test procedures. See How to Convert ASHRAE BTU to SACC.
How these facts are maintained
These facts are drawn from the DOE test-procedure final rule and Federal Register notices, manufacturer spec sheets, and major retailer listings, reviewed against our comparisons and updated on the date shown above when a rule or a listing changes. We do not publish prices or star ratings, we have never tested a unit ourselves, and we label every derived figure as derived. Full methodology at How We Evaluate.