Since 1991, Schoonmaker Heating & Air Conditioning in Santee has held CSLB license #633929 under the C-20 classification, staffing every job with NATE-certified, in-house technicians from its Prospect Avenue shop. HVAC change-outs during whole-house remodels require scheduling within the framing-to-drywall window, a phased approach coordinated with general contractors such as Blueprint Renovations on permitted residential builds. The service range spans gas furnace installation, central air conditioning replacement, air duct fabrication and repair, and custom sheet metal work for residential and light-commercial applications across San Diego County. Ductwork rerouting through finished walls and ceilings frequently requires drywall cutouts that need patching and repainting after inspection, a finishing step handled by painting contractors such as Windco Painting once the mechanical rough-in passes final sign-off. The most involved residential projects require complete duct-system redesigns with Manual D airflow calculations, return-air balancing across multiple zones, and sealed-duct verification testing per California Title 24 Section 150.0(m).