Released in 2008, the T-K3-SP is one of Takagi's residential tankless water heaters. At 13.8 inches wide and weighing only 40 pounds, its ultra-compact design allows it to be mounted on a wall or installed between two wall studs using Takagi's TK-RBO1 recess box, so it's even more inconspicuous.

The T-K3-SP features a built-in power venting system and requires Category III venting or vent caps.

It can provide an unlimited supply of hot water continuously because there is no storage tank to heat and reheat. The T-K3-SP starts heating water at 0.5 gallons per minute (GPM), and can keep that endless supply of hot water running up to a maximum flow rate of 7.0 GPM.

The T-K3-SP also offers four separate temperature settings, ranging from 113 to 167 degrees Fahrenheit, so it does not require the use of a separate remote control.
Unlike other Takagi models, the T-K3-SP is not linkable or direct vent convertible.