Once a hot tub is filled with water, electrical resistance heaters warm the water to between 100 and 104 degrees. A pump forces water through an intake hose to circulate. A valve diverter then ...

For the purpose of making a hot tub, any style can suffice ... Cold water enters at the bottom of the heater and expands. Convection moves the heated water upward, pushing it through the coil ...

"I wanted to create a way to keep a hot tub covered during use to keep the water warm and free from debris," said an inventor, from Philipsburg, QC, Canada, "so I invented The Hottub Heat Saver Cover.

Investigators with the Cary Fire Department determined the fire’s point of origin to be “around the portable hot tub’s heater and water pump.” The fire broke out in early February.