Came out to call to perform preventative maintenance on furnaces, and answer questions customer had regarding the hvac systems in the home the customer purchased recently. Home was built in 2014 and is roughly around 2,500 sqft. Customer has 2 systems which are 4 and 3 ton units. Customer had questions about the sizing of equipment, the thermostat set up, and about filters. The tonnage of the equipment is good for the home, as it has high ceilings. I did recommend having the return completely ran in hard pipe to increase the cfm in return air without having to cut more in on the 3 ton units, and will need to run another return on the 4 ton to get sufficient cfm back to the system. Customer has zone thermostats in some of the bedrooms and garage, but they are only set up to open and close the zones based on temperature. They do not control the system, only the main thermostat controls the heat and air. Customer is not sure if he wants to keep that set up or not, and said we would discus