Natural gas is a fossil fuel composed primarily of methane (70 to 90 percent) along with ethane, propane, and other hydrocarbons, serving as a leading fuel source for residential and commercial heating systems. It enters homes through underground utility lines and is measured in therms or cubic feet. Natural gas furnaces account for over 50 percent of heating systems in North America.
Safety Features and Detection
Natural gas is odorless in its natural state, so utility companies add mercaptan, a sulfur-based chemical with a distinctive rotten egg smell, for leak detection. Gas furnaces include safety controls such as flame sensors and pressure switches to prevent unsafe operation. Properly functioning furnaces produce blue flames, indicating complete combustion at temperatures around 3,000 degrees Fahrenheit.
Efficiency and Cost Effectiveness
Natural gas furnaces achieve AFUE ratings from 78 to 97 percent depending on technology. Operating costs vary by region but generally remain lower than electric heating in cold climates. Annual heating with natural gas costs approximately 30 to 50 percent less than electric resistance heating in regions with moderate to severe winters, making it the preferred choice for efficient residential heating.