Remodel Guide: High-Efficiency Furnaces Buyers Guide

Sky-high energy bills, diminishing resources and a healthy concern for our environment have brought a great deal of attention to the topic of home energy efficiency in recent years. Homeowners everywhere are struggling to spend less, use less and pollute less without giving up the warmth and comfort we've grown to cherish.

Almost 35 million homes in America are heated by natural gas-fired forced-air heating systems, by far the most popular form of central heating. Unfortunately, nearly all of these households have been sending 30% or more of their energy dollars up the furnace flue and, in doing so, each has pumped up to four tons of carbon dioxide, the "greenhouse gas," into the atmosphere every month. Most conventional forced-air furnaces operate at very low efficiencies -- some taking advantage of only half the fuel they burn.

In an effort to curb this waste and pollution, the U.S. Department of Energy (DOE) instituted rigid new standards at the beginning of 1992 that require every new furnace to turn at least 78% of its fuel into heat. Manufacturers have responded with models that, at the minimum, meet this standard and, at best, far surpass it.

The measurement for efficiency is called an Annual Fuel Utilization Efficiency (AFUE) rating. All furnaces now come posted with this rating, generally in the form of a yellow "Energy Guide" label. AFUE ratings run from the 78% minimum to the Carrier SXC's 96.7%. Though most makers list their furnaces as "high efficiency," the DOE sometimes refers to units with an AFUE higher than 90% as "high efficiency" and lower-AFUE models as "mid efficiency."

With these new high-efficiency products available, many homeowners are replacing their outdated furnaces. Replacement costs can run anywhere from $1700 to $3500, depending upon the complexity of installation. High-efficiency models represent only about $500 to $1000 more in material costs than mid-efficiency units-- and some utilities offer rebates that cover much of the difference. The payback period depends on the price of the system, local energy costs, climate and the difference in efficiency between the old and new furnaces. Yellow Energy Guides list estimated annual operating costs for furnaces given specific conditions; they're meant for comparison only. When buying a system, you should ask your dealer to help you figure actual payback.