Cesar and I performed a 5 system heating maintenance. We checked amps, sequence of operation, electrical, drains, cleanliness, filters, and safeties. The systems are performing to manufacture specifications. We have some recommendations involving cleanliness and air quality. Recommendations 1. The master bedroom has a reasonable amount of dust in the ducts. We recommend a duct cleaning be performed on it alone. 2. We advise that an ionizer be installed in the master bedroom unit to assist the filter. The filter is only designed to catch approximately 33% of the contamination in the home. The ionizer allows for better clumping of the smaller particles so the filter can catch it. 3. We recommend adding an air scrubber to the downstairs main unit. This will treat the air in a similar way as the ionizer but it has a u/v light, also.