Tankless Water Heater

Related terms

• Thermostat

  The control that calls for heating/cooling. Programmable and smart models cut energy by matching conditioning to occupancy.

• Tank Water Heater

  A storage water heater keeping a tank hot. Lowest upfront cost; standby losses and limited capacity are the trade-offs.

• Three-Way / Multi-Way Switch

  Switches controlling one fixture from two or more locations (stairs, long rooms). Adds wiring complexity in a remodel.

• Tamper-Resistant Receptacle

  An outlet with internal shutters preventing object insertion, code-required in dwelling living spaces.

• Tonnage

  AC/heat-pump cooling capacity (1 ton = 12,000 BTU/hr). Sized by a load calculation, not square footage rules of thumb — oversizing hurts…

• T&P Relief Valve

  The temperature-and-pressure safety valve on a water heater that prevents tank rupture. Must discharge per code; never plugged.

• Two-Stage / Modulating

  Equipment that runs at partial capacity most of the time for efficiency and comfort, ramping up only on extreme days.

• Subpanel

  A secondary panel fed from the main, adding circuits for a remodel, addition, garage, or shop. Requires correct 4-wire feeder and isolate…