DOE SACC vs. ASHRAE BTUs: the portable AC label explained
Portable air conditioners often show two capacities. Learn why DOE SACC is lower and which number belongs in a fair comparison.
A portable air conditioner might be advertised as “12,000 BTU” while its yellow EnergyGuide label shows 8,000 Btu/h. That does not necessarily mean either number was printed by mistake. It means the numbers came from different rating approaches.
What ASHRAE capacity represents
The larger number commonly labeled ASHRAE is based on measured cooling capacity under a room-air-conditioner test method. It describes what the refrigeration system removes under specified laboratory conditions before the federal portable-unit adjustments are applied.
That matters because a portable AC keeps the entire refrigeration system indoors. Its condenser rejects heat through a duct, and many units exhaust room air outdoors. Those details create losses that the larger capacity number does not fully express as net room cooling.
What DOE SACC accounts for
The Department of Energy defines seasonally adjusted cooling capacity, or SACC, for portable air conditioners. The federal procedure adjusts measured cooling for important effects including:
- Heat transferred from the exhaust and inlet ducts back into the room.
- Warm outdoor air pulled into the conditioned space because of the unit’s airflow.
- Performance at weighted seasonal test conditions.
For a conventional single-speed, single-duct unit, the procedure calculates adjusted capacity at 95°F and 83°F, then weights those results. This is why SACC is normally lower than the accompanying ASHRAE figure.
SACC is a standardized laboratory metric designed to represent important portable-AC losses. It is more useful for comparison, but it is not a promise about the temperature in every room.
Which number should you use?
Use DOE SACC when comparing one portable AC with another and when estimating whether a portable unit suits a room. If a retailer lists only “12,000 BTU,” open the EnergyGuide label or specification sheet and determine which rating it is.
When comparing portable and window units, compare the federally rated capacities rather than placing a portable unit’s ASHRAE headline next to a window unit’s standard capacity.
Why no conversion calculator works reliably
There is no fixed ratio that converts every ASHRAE rating to SACC. Duct design, airflow, infiltration, test results, hose configuration, and variable-speed behavior differ. A rule such as “multiply by 0.65” may accidentally match one model and misrepresent another.
Use the model-specific EnergyGuide label instead. The FTC requires portable-AC labels to display federally determined capacity along with standardized energy information.
Read the rest of the label
Capacity tells you how much cooling the unit can deliver under the test. It does not tell you everything about ownership. Also compare:
- Combined energy efficiency ratio or the efficiency metric on the current label.
- Estimated annual energy use and standardized annual cost.
- Noise information from consistent test conditions, when available.
- Hose configuration and window-kit dimensions.
- Condensate handling in your climate.
- Electrical requirements and the manufacturer’s extension-cord policy.
The most defensible comparison uses the lower SACC number openly and explains the installation losses rather than hiding them behind the largest figure available.
Primary sources
What we checked
Sources were last checked on August 27, 2026. Product specifications and regulations can change; verify current documentation before purchasing or installing equipment.