Gas furnaces installed at altitudes above what height require adjustments to operate properly?

Gas furnaces installed at altitudes above 2,000 feet require adjustments to ensure they operate properly due to the effects of atmospheric pressure on combustion. As altitude increases, the air pressure decreases, resulting in a thinner mixture of oxygen available for combustion. This lower oxygen concentration can lead to incomplete combustion, reduced efficiency, and difficulty in maintaining the desired heating output.

Manufacturers usually provide guidelines for adjusting furnaces to accommodate the decreased oxygen levels. These adjustments may include changing the combustion air supply, altering the gas pressure settings, or modifying burner assemblies to ensure the furnace runs efficiently and safely at higher elevations.

Because 2,000 feet is the threshold where these adjustments typically become necessary, operating a gas furnace above this altitude without the required modifications can lead to performance issues, posing risks not only to energy efficiency but also to safety concerns such as the production of harmful carbon monoxide.