Performed 3 system heating maintenance. Both whirlpool furnaces need blower wheels to be chemically cleaned to restore balance and efficiency. One whirlpool system has overflow switch, highly recommend installing a second one on the other system as well. Newer Lennox unit needs surge protector to keep electrical components from damage. Added bleach to all drain lines and condensate pumps. Homeowner has already recently changed. Surge protector $212.5. E-z flow switch $169