Rheem water heaters are devices that heat water through gas, electric or solar power. The heaters are available as standard tanks or tankless boxes, which heat water on demand.
Residential Rheem tank water heaters maintain up to 80 gallons at a constant temperature of about 120 degrees Fahrenheit. Rheem tankless heaters are much smaller because they heat the water as it passes through the device rather than holding a large volume of water. Tankless devices offer the option of raising or lowering the water temperature to accommodate different uses. Tanks usually are less expensive to install, although tankless units use less energy.