American Standard’s Platinum ZM Heat Pump (also known as the Heritage 20 Heat Pump) includes the company’s Dual Duration compressors and has a rating of up to 19 SEER. The system uses proprietary software to coordinate and communicate with other system components. The pump features an aluminum coil, and rust-resistant coating, screws and basepan. Its two compressors provide two-stage heating and cooling, often operating at half-capacity to cut residential heating and cooling costs, according to the company.

American Standard.