Eternal Hybrid Water Heating Systemby Grand Hall

    Using a counterflow design and multipass heat exchanger technology, the Eternal GU32 hybrid water heating system maintains 86% thermal efficiency with consistent pressure, the maker says. Easy installation and PVC-ventability make Eternal popular among plumbers. A computer monitoring system helps prevent scalding or cold-water shock, and the appliance has near-zero greenhouse gas emissions. 877.934.7455. www.eternalwaterheater.com.