Heating system maintenance and checks on both furnaces. Cleaned the flame sensors on both furnaces. Will be back tomorrow to install new igniters, both are reading below manufacture specifications. Cleaned both furnaces as best as possible. Appears to not have had maintenance done since the systems were installed 12 years ago. Both systems are 12 years old. Average is 10-15 years. Recommend continuing maintenance to avoid any future issues and to extend the life.