Bosch Thermotechnology’s Tronic 5000C and 6000C electric tankless water heaters in kW input models WH17 (Tronic 6000C), WH27 (Tronic 6000C) and WH36 (Tronic 5000C) are 97% efficient with minimal stand-by loss. The compact and lightweight wall-mounted units allow for virtually endless hot water for up to three major applications at a time. They also come with a filter screen on the units’ inlet. The models require hard wiring through double-pole breakers in the breaker box and also require varying amperage service.