Our Services Our trained Staff specializes in assisting in engineering and designing for your specify recovery needs. Providing you with projected saving based upon your location, run time and application type. We can provide you with our own in house trained installation contractors or work with your designated HVAC contractor, in house maintenance crew or preferred contractor. Hartig Heat Exchangers are delivered to your site duct connect ready, start ready fans, with or without indirect evaporative spray. High temperature or low temperature ready, housed in material designed for your application.