Performed a complete heating system maintenance and inspection. 2025 Gas system. Inspected and tested all electrical components and safety controls on the indoor unit; all components tested within manufacturer specifications. Verified system temperatures: return air temperature measured at 73°F; supply air temperature measured at 116°F and rising. Confirmed air filter was recently replaced by client; filter size is 20” x 25” x 4”. Provided estimate to have Aprilaire upgrade box installed for better filtration in the home. I visually inspected the outdoor unit, The outdoor unit was in good condition. Provided estimate to have surge protection installed. Confirmed system was operating properly and heating upon departure.