The study shows that a consumer who purchases a home heating system based only on a comparison of AFUE ratings may actually spend as much as $800 per year more on fuel with one system, compared to a second system with a nearly identical AFUE rating. This difference in real annual efficiency is determined by a characteristic of all heating systems called idle loss, a performance factor which is not evaluated for AFUE on units which provide both heat and hot water. Idle loss includes two primary areas of heat loss on conventional home heating systems: standby loss, and jacket loss. Also almost entirely neglected are draft regulator, draft hood, and room air losses.
Only when idle losses are reduced or eliminated is it possible for real efficiency to approach the AFUE rating of a heating product. In fact, significant idle losses may lead to actual efficiencies as low as 55%. This real annual efficiency rating may determine system performance even when the government AFUE rating measures in the 80-95 percentile range.
The study also reports that the cold start and cold finish operation of Energy Kinetics’ System 2000 has the lowest overall idle loss and the best annual efficiency performance among all home heating systems tested to date, including 95% AFUE condensing gas and oil systems.
The study revealed that outdoor reset controls may save 5% to 15%, but need trial and error adjustments over the course of a heating season. By comparison, using proven Hybrid Energy Recovery,® System 2000 automatically adapts to heating loads. The result is a home heating system that delivers the best-documented efficiency. View our efficiency checklist to see how your heating system idle loss compares.