Performed furnace maintenance on two systems Lennox heaters. House has two heaters informed client that next time renewal occurs they will be charged for two system due to an error on our part for only signing them up for one. Furnace a Maintenance checked out properly. System was covered in dust and debris inside the indoor blower cabinet. Client mentioned before they did have washable filters that were replaced with Merv 8 filters by the last technician. Informed them that 5 inch filtration Will improve Indoor Air quality And keep system Cleanly. Presented Merv 11 filter rack upgrade and clients would like to hold off at the moment due to pricing. Will be emailing over information system is fully operational and heating upon departure filter sized for client: x2-20x30x1, 14x14x1, 12x24x1