How to Convert ASHRAE BTU to SACC
There is no official universal formula to convert an advertised ASHRAE BTU rating into a SACC rating. SACC is a separate, independently-run DOE test result for each specific unit, not a fixed percentage reduction you can apply generically. Across the models in our SACC Reality Index, the gap ranged from about 14% to 50% for different units — there is no single multiplier that applies universally.
The one thing to know: Every 'gap percentage' on this site is a DERIVED figure we calculate as (advertised BTU minus disclosed SACC BTU) divided by advertised BTU, using only the two numbers each manufacturer has published. We do not run our own cooling tests, and we are not asserting any brand is misrepresenting its product — both figures are legitimate results of two different test procedures. The gap is a transparency measure, not an accuracy accusation.
Why there's no shortcut formula
SACC depends on physical characteristics specific to each unit's design — hose configuration (single, dual, or hose-in-hose), compressor type (fixed-speed vs. inverter), cabinet sealing, and how the exhaust path is engineered. Two units with an identical 14,000 BTU advertised rating can have meaningfully different disclosed SACC ratings because their internal designs differ. Any "rule of thumb" percentage you see online (including the ranges cited on this site) describes an observed pattern across sampled units, not a physical law you can apply to a specific unit you haven't checked.
What we found instead of a formula
| Model | Advertised BTU | Disclosed SACC BTU | Derived gap |
|---|---|---|---|
| Midea Duo MAP14HS1TBL (hose-in-hose, inverter) | 14,000 | 12,000 | 14.3% |
| TURBRO Greenland PAC10KUS (single hose) | 14,000 | 10,000 | 28.6% |
| LG LP1419IVSM (single hose, inverter) | 14,000 | 10,000 | 28.6% |
| Whynter ARC-14S (dual hose) | 14,000 | 9,500 | 32.1% |
| BLACK+DECKER BPACT14WT (single hose) | 14,000 | 7,700 | 45.0% |
| SereneLife SLPAC8 (single hose) | 8,000 | 4,000 | 50.0% |
Full sourcing for each row is in the SACC Reality Index. Notice that two single-hose, inverter-equipped 14,000 BTU units (TURBRO and LG) landed at the exact same 28.6% gap here — a coincidence worth noting, not a rule to extrapolate from.
What to do instead of estimating
Look up the specific model's own disclosed SACC figure — on the manufacturer's site first, then a major retailer listing. If no SACC figure is published anywhere, don't estimate one; treat the listing's advertised BTU and any sq ft claim with more skepticism, per Is SACC Disclosure Required?.
This page reports an observed pattern across disclosed figures, not a scientific formula or a guarantee for any unmeasured unit.
Frequently Asked Questions
No official universal formula exists -- SACC is a separate test result, not a fixed mathematical conversion of the ASHRAE number. The relationship varies by unit (typically a 15-50% reduction), depending on hose configuration, compressor type, and how the original ASHRAE figure was set. The only reliable SACC figure for a specific unit is the one the manufacturer discloses for that model.
Gap percentages describe the relationship already observed between two disclosed numbers for a specific unit -- they are descriptive, not predictive. You cannot reliably apply one unit's gap percentage to estimate another unit's undisclosed SACC rating.
Look up the exact model number on the manufacturer's own site, which is more likely to disclose the DOE SACC figure than a third-party retailer listing. If no SACC figure exists anywhere, treat the advertised BTU and any sq ft claim with skepticism and size conservatively.
It can help by reducing cycling losses, one of the three factors SACC accounts for, but it doesn't eliminate infiltration or duct heat leakage. In our SACC Reality Index, the inverter-equipped Midea Duo showed the smallest gap (14.3%) among the units we reviewed, though hose design (hose-in-hose) is likely also a contributing factor.