Tonnage

Related terms

• Load Calculation (Electrical)

  An NEC calculation of total demand to verify the service/panel can carry added loads. The basis for whether a service upgrade is required.

• Two-Stage / Modulating

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

• Three-Way / Multi-Way Switch

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

• UEF (Uniform Energy Factor)

  The standardized water-heater efficiency metric for comparing models; higher UEF means less energy per gallon delivered.

• Thermostat

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

• Variable-Speed Blower

  An ECM blower that ramps output to match demand for steadier temperatures, better humidity control, and lower electricity use than single…

• Tankless Water Heater

  An on-demand heater with endless hot water and no standby loss. Higher install cost; gas units often need larger gas/vent lines.

• Vent Stack

  The piping admitting air so drains flow without siphoning traps, terminating through the roof. Adding fixtures often means new venting.