IMPROVING RESIDENTIAL GAS FURNACE AND BOILER INSTALLATION PRACTICES

Jennifer Thorne

December, 1998

Introduction

Space heating is the largest energy end-use in the majority of U.S. homes. The first federal minimum efficiency standards for residential furnaces and boilers were mandated by the National Appliance Energy Conservation Act (NAECA) of 1987. In 1992, standards went into effect requiring manufacturers to develop more efficient products to meet the minimum of 78 Annual Fuel Utilization Efficiency (AFUE) for gas furnaces and 80 AFUE for gas boilers. Since that time, governments and utilities have sponsored programs to encourage consumers to purchase heating equipment that surpasses the minimum efficiency mandated by federal standards. Largely as a result of these efforts, the average efficiency of new equipment purchased now exceeds the minimum standards. Indeed, more than 85 percent of gas furnaces sold in 1997 were units with AFUE of 80 percent or more and a full 25 percent of shipments rated 88 percent or higher (GAMA 1998).

Yet additional efficiency gains remain unrealized due to a number of installation problems common to residential gas furnace and boiler systems that cause the units to operate outside their design or test configuration. Studies conducted over the past 20 years have highlighted installation errors and developed estimates of the adverse impacts of improper installation on equipment-operating efficiency in the heating, ventilating, and air conditioning (HVAC) field. These studies reveal that energy losses from poor installation can outweigh the efficiency gains from installation of equipment with high-efficiency ratings. In addition, poor installation can lead to comfort problems in the home, increased maintenance costs, and shorter equipment life.