Heat pump efficiency is measured using Coefficient of Performance (COP). The coefficient of performance (COP) is a measure of the efficiency of a heat pump, defined as the ratio of useful heat ...

The Betasso Overlook is a set of three A-frame cabins in Colorado, operating 100% gas-free, thanks to clever architectural design.

Local officials say a proposal to regulate the sale of gas heaters will burden residents while proponents say it will improve air quality.