The 59SP5A Multipoise Performance™ Boost Condensing Gas Furnace features SEER-boosting year-round electrical efficiency when paired with a compatible condensing unit. Energy efficiency is at the heart of this furnace with up to 96.5% AFUE gas efficiency and the electrically-efficient basic ECM blower motor. This gas furnace also features 4-way multipoise installation flexibility, and is available in nine model sizes. All sizes except the 26,000 BTUH model can be vented for direct vent/two-pipe, ventilated combustion air, or single-pipe applications. The 26,000 BTUH model can use the same 2-pipe venting system using outside air for combustion, but is not considered direct-vent. All units meet California Air Quality Management District emission requirements, are design certified in Canada, and are certified for mobile/manufactured home use.