The Tranquility 22 Digital Series geothermal system has a small footprint that makes it ideal for tight spaces. Available in vertical or horizontal configurations, the system features a two-stage compressor, a variable-speed fan, and digital controls. It’s available in several capacities, all of which are eligible for 30 percent federal tax credits. ClimateMaster. 877-436-6263. www.climatemaster.com.