There are an estimated 350,000 residential pellet-fired heaters currently in use in the United States. Even with the recent introduction of this kind of heaters, there has been significant improvement in reliability, efficiency, and air pollutant emissions in current models as compared to the earliest models. Electronic and microprocessor control of combustion air, fuel feed, and convection fans is primarily responsible for the improvement. Unfortunately, air emissions and efficiency data in the open literature and in government reports available to air quality and energy planners and regulators are still based on the performance of the earliest models introduced. Air emission testing and efficiency testing on a new commercially available under feed and top feed residential heaters burning hardwood and softwood pellets were conducted. The results were compared with data from earlier models. Reductions in air emissions were documented. The data from both the old- and new-technology stoves confirm that pellet-fired heaters offer an environmentally sound option for the utilization of wood waste for home heating.