Arrived at home for two system heat maintenance inspection. Our client provided filters to be replaced today. After replacing the filters, I proceeded to test and inspect both furnished units. I began by first clean the flame sensor, pressure, switch, ports, and cleaned out the furnace cabinet. I also did a visual inspection on both blower motors and found them to be clean at this time. I tested to ensure that the fire safety for both furnaces were working properly as well as tested inducer and blower motors for each unit. Everything passed inspection today. I discussed protecting equipment with surge protection but our client. Declined at this time. Both units are running properly on departure