Lockout temperature

A lockout temperature is an outdoor temperature setting that stops the compressor or the backup heat from running.

Editorial staffEdited 6d ago by heatpumpwiki

A lockout temperature is a thermostat or control setting based on outdoor temperature. There are two kinds:

Compressor lockout: stops the heat pump below a set outdoor temperature. Resideo's T6 Pro offers "Compressor Lockout / Balance Point" from 5°F to 60°F, or off.^{[Source 1]} ecobee calls it Compressor Min Outdoor Temperature.^{[Source 2]}
Backup heat lockout: stops backup heat above a set outdoor temperature. The T6 Pro's "Outdoor Lockout Backup Heat" ranges from 5°F to 65°F, or off.^{[Source 1]} ecobee calls it Aux Heat Max Outdoor Temperature.^{[Source 2]}

A lockout is a setting. The equipment's own minimum operating temperature, which NRCan calls the cut-off temperature, is a property of the heat pump.^{[Source 3]} See Heat pump backup heat and lockout temperatures and Thermal and economic balance points.

Sources

AHRI certificateAn AHRI certificate shows the certified efficiency ratings for one exact combination of outdoor and indoor heat pump equipment.
Aux heat (auxiliary heat)Aux heat is a backup heat source that a heat pump thermostat turns on automatically when the heat pump needs help.
Btu (British thermal unit)A Btu is the heat needed to raise one pound of water by one degree Fahrenheit, and heat pump capacity is given in Btu per hour.
COP (coefficient of performance)COP is the heat a heat pump delivers divided by the electricity it uses, at one set of conditions.
DefrostDefrost is the cycle in which a heat pump briefly reverses to melt frost off its outdoor coil.
EER2EER2 is a cooling efficiency rating at a single hot test condition, in Btu per hour of cooling per watt.