High Altitude Furnaces: How Altitude Impacts Heating Your Home Posted on September 23, 2019 Colorful leaves, autumnal decor, and cozy “sweater weather” make fall a beloved season. For those at sea level, fall may seem far off, but in high-altitude areas, the season can already bring cool temperatures or even early snowfall. If you live at higher elevations and need a new heating system, there are specific factors to consider. In this guide, we’ll explain the science behind heating at altitude, discuss furnace requirements, and highlight the best furnaces for high-altitude use. Heating Considerations at High Altitude At high elevations, air density and oxygen levels are lower than at sea level. This dry, thin air affects how efficiently heating systems operate because more airflow is needed to heat a space at altitude. The result? Homes at higher elevations require more powerful heating systems. Standard furnaces designed for sea level will underperform at altitude unless they are modified for optimal operation. This can lead to poor performance, reduced efficiency, and higher energy bills. High Altitude Furnace Requirements According to National Geographic, elevations over 8,000 feet are considered high altitude. However, even at 2,000-6,000 feet, altitude impacts heating efficiency. For example, a 3,000-square-foot home at 2,000 feet will require a larger furnace than the same-sized home at sea level. When purchasing a furnace: Opt for an altitude conversion kit if your elevation is over 2,000 feet. For homes above 6,000 feet, ensure you purchase a kit designed for high-altitude heating. High Elevation Furnace Kits If you’ve purchased a standard furnace for sea-level operation, don’t worry—it can be modified for altitude. A high altitude furnace kit includes components optimized for efficient operation at elevation. Typical components in a furnace altitude kit include: Pressure switch Burner orifices Gas valve springs Derating the Furnace: Before using a kit, the furnace must be derated, which reduces its input rate. Most systems require a 4% reduction for every 1,000 feet above sea level, but always check your manual or consult a heating professional. Best Furnaces for High Altitude If you’re ready for a brand-new heating system, there are excellent furnaces designed for high-altitude use. The main fuel options are liquid propane and natural gas. High Altitude Propane Heaters Williams Furnace Company 550823 Forsaire 55,000 BTU Top Vent Counterflow Furnace – This wall-mounted furnace maximizes space while providing efficient heat distribution. It pulls air in from the top, heats it internally, and pushes warm air out from the bottom for even coverage. Williams Furnace Company 3003 30,000 BTU Gravity Direct Vent Wall Furnace – Ideal for smaller homes, this direct vent system draws clean air from outside to heat your space efficiently. Both options are factory set for elevations up to 2,000 feet but can be converted for higher elevations with an affordable kit. Natural Gas Furnaces For natural gas heating at altitude, consider the Williams 6501A 65,000 BTU Vented Hearth Heater. This efficient, quiet heater vents to the outside and features an optional blower for improved heat circulation. An altitude conversion kit is available for just $25. Garage Heaters Need to heat a garage, warehouse, or barn at high elevation? The Reznor UDAP-100 100,000 BTU Power Vented Gas Heater is an excellent choice. With 83% thermal efficiency, it’s perfect for commercial or residential spaces. Features include: Designed for use up to 2,000 feet Valve outlet adjustments for elevations between 2,001-6,000 feet Optional Reznor DJ20 High Altitude Kit for elevations above 6,000 feet Next Steps Whether you’re upgrading to a high-altitude furnace or modifying an existing system, Total Home Supply has everything you need. We offer: High altitude furnace kits for modifying standard systems A wide selection of vented gas heaters designed for altitude Remember: Furnace installation, modifications, and servicing should always be completed by a qualified HVAC professional. Shop High Altitude Furnaces Mickey Luongo Mickey is the resident heating and air conditioning expert with over 15 years of experience in the industry.
Colorful leaves, autumnal decor, and cozy “sweater weather” make fall a beloved season. For those at sea level, fall may seem far off, but in high-altitude areas, the season can already bring cool temperatures or even early snowfall. If you live at higher elevations and need a new heating system, there are specific factors to consider. In this guide, we’ll explain the science behind heating at altitude, discuss furnace requirements, and highlight the best furnaces for high-altitude use. Heating Considerations at High Altitude At high elevations, air density and oxygen levels are lower than at sea level. This dry, thin air affects how efficiently heating systems operate because more airflow is needed to heat a space at altitude. The result? Homes at higher elevations require more powerful heating systems. Standard furnaces designed for sea level will underperform at altitude unless they are modified for optimal operation. This can lead to poor performance, reduced efficiency, and higher energy bills. High Altitude Furnace Requirements According to National Geographic, elevations over 8,000 feet are considered high altitude. However, even at 2,000-6,000 feet, altitude impacts heating efficiency. For example, a 3,000-square-foot home at 2,000 feet will require a larger furnace than the same-sized home at sea level. When purchasing a furnace: Opt for an altitude conversion kit if your elevation is over 2,000 feet. For homes above 6,000 feet, ensure you purchase a kit designed for high-altitude heating. High Elevation Furnace Kits If you’ve purchased a standard furnace for sea-level operation, don’t worry—it can be modified for altitude. A high altitude furnace kit includes components optimized for efficient operation at elevation. Typical components in a furnace altitude kit include: Pressure switch Burner orifices Gas valve springs Derating the Furnace: Before using a kit, the furnace must be derated, which reduces its input rate. Most systems require a 4% reduction for every 1,000 feet above sea level, but always check your manual or consult a heating professional. Best Furnaces for High Altitude If you’re ready for a brand-new heating system, there are excellent furnaces designed for high-altitude use. The main fuel options are liquid propane and natural gas. High Altitude Propane Heaters Williams Furnace Company 550823 Forsaire 55,000 BTU Top Vent Counterflow Furnace – This wall-mounted furnace maximizes space while providing efficient heat distribution. It pulls air in from the top, heats it internally, and pushes warm air out from the bottom for even coverage. Williams Furnace Company 3003 30,000 BTU Gravity Direct Vent Wall Furnace – Ideal for smaller homes, this direct vent system draws clean air from outside to heat your space efficiently. Both options are factory set for elevations up to 2,000 feet but can be converted for higher elevations with an affordable kit. Natural Gas Furnaces For natural gas heating at altitude, consider the Williams 6501A 65,000 BTU Vented Hearth Heater. This efficient, quiet heater vents to the outside and features an optional blower for improved heat circulation. An altitude conversion kit is available for just $25. Garage Heaters Need to heat a garage, warehouse, or barn at high elevation? The Reznor UDAP-100 100,000 BTU Power Vented Gas Heater is an excellent choice. With 83% thermal efficiency, it’s perfect for commercial or residential spaces. Features include: Designed for use up to 2,000 feet Valve outlet adjustments for elevations between 2,001-6,000 feet Optional Reznor DJ20 High Altitude Kit for elevations above 6,000 feet Next Steps Whether you’re upgrading to a high-altitude furnace or modifying an existing system, Total Home Supply has everything you need. We offer: High altitude furnace kits for modifying standard systems A wide selection of vented gas heaters designed for altitude Remember: Furnace installation, modifications, and servicing should always be completed by a qualified HVAC professional. Shop High Altitude Furnaces
January 2, 2021 at 8:43 PM Catherine Barley says: Thank you for this great article on the considerations of higher altitude heating systems. Currently I live at 5,682′ in Paonia Colorado. My house is small 1,100 sq ft with a couple of rooms I can close off in the event of a power failure. My current heating system is hot water baseboard and works well. I wish to find a natural gas ventless heater for emergency use during power outages that I can locate in the heart of the house. Can you make a recommendation? Most of the catalytic heaters or blue flame heaters that are ventless say “May not work properly over 4,200ft” Thanks very much. Reply
January 4, 2021 at 10:28 AM Mickey Luongo says: There are no vent free heaters that will work at your altitude. Sorry. Reply
January 5, 2023 at 5:21 PM John Thayer says: My house elevation is 10,000 feet. I would like to install a Williams direct vent wall furnace but they are only rated up to 8,000 feet. How can I solve this problem? Thanks Reply
January 6, 2023 at 10:33 AM Mickey Luongo says: Williams heaters are not certified for use above 8,000 ft. I would recommend taking a look at a Rinnai heater which is rated for up to 10,200 ft. Reply
December 3, 2024 at 9:29 AM John Blankenship says: Are there any propane space heaters that can be used at 8,000 ft? Reply
December 3, 2024 at 9:32 AM Mickey Luongo says: There are plenty of vented propane heaters that would work at 8,000 ft, but ventless propane heaters cannot be used at that altitude. Reply
