Lennox makes the most efficient residential equipment on the market the SL28XCV hits 28 SEER2. But it costs more and parts are proprietary.

Daikin offers the strongest warranty (12 years parts when registered) and the best inverter technology at a mid premium price.

Rheem is the value play solid reliability, 10 year warranty, easier parts availability, and 15 25% less expensive than Lennox for comparable specs.