The Trane company began manufacturing heating devices in 1910 after company founder James Trane invented a low-pressure heating system called the Trane Vapor Heating System. The Trane XE90 is a single-stage gas furnace that was marketed as a high-efficiency heating unit. Each model of the XE90 range boasts a 90+ AFUE (annual fuel utilization efficiency) percentage. This is the percentage of heat energy used to heat the conditioned space, with the remaining energy being lost with exhaust material.

Trane XE90 General Specifications

Trane's XE90 furnaces are housed in a heavy-duty cabinet made from galvanised steel measuring 40 inches in height and 28 inches in depth. The width of the cabinet varies by model. Each furnace can be positioned either vertically or horizontally and is fitted with a one-piece heat exchanger, which eliminates the dangers of cracking and fracturing associated with welded heat exchangers. The XE90 also features a microelectronic controller, an adaptive hot surface igniter, multiport in-shot burners and a cleanable filter.

XE90 Model Types

XE90 models are divided into direct and non-direct vent units. A direct vent furnace is a furnace that draws the air used for combustion directly from the outside and then expels the exhaust products directly back to the outside atmosphere. A non-direct vent furnace may draw air from a piping system, but does not access the outside directly. These two groups are then divided into upflow and downflow versions. An upflow furnace draws air in through the lower part of the unit and expels it through the upper part. A downflow furnace works in the opposite way.

XE90 Non-Direct Vent Furnaces

Model numbers preceded with the code "TUC" are upflowing, non-direct valve furnaces. The TUC040C924B, TUC060C936B and TUC080C942B units all share a width of 17.5 inches and have capacity outputs of 37,000 BTUH, 56,000 BTUH and 74,000 BTUH, respectively. A BTUH – or British Thermal Unit per Hour – is a measurement of heat energy equivalent to the amount of energy required to raise the temperature of one pound of water by one degree Fahrenheit at atmospheric pressure. The TUC100C948B has a width of 21.0 inches and produces 94,000 BTUH, while the TUC 100C960B and the TUC 120C960B share a width of 24.5 inches and have outputs of 93,000 BTUH and 112,000 BTUH, respectively. All upflowing XE90s share a 92.1 percent AFUE rating.

XE90 Non-Direct, Downflowing Furnaces

Model numbers with a prefix of "TDC" are downflowing furnaces with non-direct vents. The TDC040C924B, TDC060C936B and TDC080C942B models all have the same width of 17.5 inches but differ in their capacity outputs, delivering 38,000 BTUH, 56,000 BTUH and 74,000 BTUH, respectively. The 21-inch TDC100C948B model delivers 93,000 BTUH while the 24.5-inch TDC120C960B model delivers 112,000 BTUH. All downflowing XE90s share a 91.0 AFUE rating.

XE90 Direct Vent Models

Model numbers beginning with "TUX" are upflowing, direct vent models, whereas model numbers beginning with "TDX" are downflowing. The TUX0404C924C, the TUX060C936C and the TUX080C942C models share their 17.5-inch width with their downflowing counterparts. The models also share their respective 38,000 BTUH, 56,000 BTUH and 74,000 BTUH outputs with their TDX-prefixed cousins. At higher widths the outputs begin to differ; the TUX100C948C and TDX100C948C models share a 21-inch width, but the downflowing model has an output of 94,000 BTUH to the upflowing unit's 93,000. The 24.5-inch TUX120C960C unit, however, outperforms its TDX-prefixed counterpart with 113,000 BTUH compared to 110,000. The TUX range also includes the 21-inch TUX080C960C which, along with the TUX100C960C, does not have a downflowing equivalent. These two units produce 76,000 BTUH and 93,000 BTUH respectively.