11 Tips for Proper Manual J Calculations for Geothermal Contractors Many geothermal and general contractors pay a subcontractor to perform Manual J calculations when its required. Accurate heating and cooling loads are absolutely critical to properly designing a geothermal system (See 4 Steps to Designing a Geothermal System) and according… Continue reading “11 Tips for Proper Manual J Calculations for Geothermal Contractors”