Arrived onsite customer has a water heater, and furnace that she wanted serviced. Immediate noticed that the exhaust for the furnace was choked down from 4-3 inch, this is a big issue as you are not allowed to reduce down venting size. This can effect the combustion from the furnace. Presented pricing for repairs, and pricing to service the equipment. Customer approved work. Corrected the venting, confirmed all venting in the attic was in good shape. Serviced the furnace. In-depth measurements are in the attached form. Completed plumbing inspection as well. Only issue present with the plumbing was a section of pipe coming from the master bathroom that was slightly back graded. Water heater temperature and pressure relief line is pvc which is not up to code. Water heater is 7 years old, average life span is 8-10 years. Furnace is 14 years old average life span is 10-15 years. Recommended to the customer that we maintain these units annually to increase life expectancy. Thank you for c