5 Series 500R11 Indoor Splits are designed for indoor use where all-in-one systems would be difficult to install, like attics or crawl spaces. When connected to our 5 Series SAH Air Handler the unit can efficiently heat and cool your entire home. When combined with a fossil fuel furnace, the system automatically selects the most efficient fuel source for your home regardless of outside temperatures. Because there is no outdoor fan like ordinary air conditioners or heat pumps, the unit is not susceptible to weather and external damage. All 5 Series 500R11 units utilize ozone-safe R-410A refrigerant and utilize WaterFurnace's newest generation of controls, Aurora, for simplified troubleshooting and setup. The 5 Series Indoor Split provides the amazing efficiency of geothermal with the versatility of a split for any application.