MRCOOL O-ES-18-HP-C-230C-O1: certified ratings
Cooling 18,000 BTU/h · SEER2 up to 21.4 · HSPF2 up to 11 · up to 100% of 47°F heating capacity at 5°F · Cold climate: Yes
ENERGY STAR lists 1 certified indoor pairing for this outdoor unit. Series: O-ES Series. Refrigerant: R-454B. Compressor: continuously variable (inverter), per ENERGY STAR.
All certified pairings (highest HSPF2 first)
| Indoor unit | Series | Cooling BTU/h | SEER2 | EER2 | HSPF2 | Heat 47°F | Heat 17°F | Heat 5°F | % of 47°F cap. at 5°F | COP 5°F | Cold climate | Refrigerant | AHRI ref. | ENERGY STAR record |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| O-18-HP-WMAH-230C-O | O-ES Series | 18,000 | 21.4 | 12.5 | 11 | 18,000 | 18,000 | 18,000 | 100% | 1.92 | Yes | R-454B (GWP:470 | Lower GWP) | 217447807 | 4428967 |
"% of 47°F capacity at 5°F" = heating capacity at 5°F ÷ heating capacity at 47°F, both from the ENERGY STAR record (ENERGY STAR's cold-climate designation requires ≥70% and COP ≥1.75 at 5°F; criteria).
Rough running-cost yardstick (top-rated pairing)
| kWh per 1,000 full-load hours | Cost at U.S. avg rate | |
|---|---|---|
| Cooling (18,000 BTU/h ÷ SEER2 21.4) | 841 | $154 |
| Heating (18,000 BTU/h ÷ HSPF2 11) | 1,636 | $300 |
Cost estimates: cooling kWh ≈ cooling capacity × full-load hours ÷ SEER2 ÷ 1,000; heating kWh ≈ 47°F heating capacity × full-load hours ÷ HSPF2 ÷ 1,000. "Per 1,000 full-load hours" is a yardstick for comparing systems, not a prediction of your bill; your hours depend on climate, house and settings. Rate: U.S. average residential 18.31¢/kWh (EIA, July 2026 (preliminary)).
Estimate with your own hours and rate · Compare with another system
Similar-capacity single-zone units from other DIY brands
| Outdoor unit | Best SEER2 | Best HSPF2 | Best % cap. at 5°F | Cold climate |
|---|---|---|---|---|
| Senville SENE-18EL-IHH | 25.6 | 16.2 | 113% | Yes |
| Senville SENE-18EL-OH | 25.6 | 16.2 | 113% | Yes |
| Pioneer YN018GMSI24RPG | 23.8 | 13.5 | 77% | Yes |
| ACiQ EZ-18ZPL-HP230B | 22.5 | 11.5 | 71% | Yes |
| ACiQ ES-18Z-M2B | 22.9 | 10.5 | 66% | No |
| Pioneer WS018GMFI20HLD | 20.5 | 10.5 | 67% | No |
| Pioneer YN020GLSI24M2G | 24 | 10.5 | 80% | Yes |
| Senville SENA/18HF/MOQ | 22.9 | 10.5 | 66% | No |
See MRCOOL on the manufacturer's site (plain link, not an affiliate link)
We have not tested or installed this equipment. Data gaps: price, sound level, line-set length, warranty and installation requirements are not in ENERGY STAR data. Confirm the AHRI reference number on your quote matches a certified pairing.