What Causes Facet Syndrome? Facet syndrome is generally the result of the natural aging process. However, the initial cause of arthritis, or facet syndrome, may also be an injury or overuse of the joints in youth. Another possible cause of facet disease is spondylolisthesis, which is when one vertebra â usually in the lumbar spine â slips forward over the lower vertebrae. When the facet joints become inflamed due to injury or age, the result is stiffness and pain.
An energy recovery ventilator (ERV) is a type of mechanical equipment that features a heat exchanger combined with a ventilation system for providing controlled ventilation into a building.
Both types include a heat exchanger, one or more fans to push air through the machine, and controls. There are some small wall- or window-mounted models, but the majority are central, whole-house ventilation systems with their own duct system or shared ductwork. The main difference between a heat-recovery and an energy-recovery ventilator is the way the heat exchanger works.