ASHP: Air-source heat pump.
Block Load: Heating and cooling load for entire conditioned space.
BTU/h: British Thermal Units per hour. Rate of energy use or transfer equivalent to 0.293 Watts.
ccASHP: Cold climate air-source heat pump. ccASHPs have improved performance in colder weather, including a lower thermal balance point temperature than standard air-source heat pumps.
Climate zones: Regions of Canada that have a similar number of heating degree days (HDD) in the heating season. Canada is subdivided into six climate zones (i.e. Zones 4, 5, 6, 7A, 7B and 8), ranging from <3000 HDD (Zone 4) to ≥7,000 HDD (Zone 8).
COP: Coefficient of performance is a dimensionless ratio used to indicate heating or cooling efficiency of a heat pump at a specific outdoor temperature. The COP of a heat pump is the rate of heat (or cooling) delivered divided by rate of electricity used by the heat pump. Higher COP ratings indicate higher efficiencies. The COP of a heat pump in heating mode declines with decreasing outdoor air temperature, and in cooling mode the COP declines with increasing outdoor air temperature. A heat pump operating with a COP of 3.0 at a particular outdoor temperature will deliver 3 kW of heat (equivalent to 10,250 BTU/h) for each kW of electricity consumption.
CSA: Canadian Standards Association
Cut-off control: A control device that restricts the operation of a heat pump or backup heating system to a predetermined range of outdoor temperatures.
Cut-off temperature: The outdoor temperature, below which the operation of an air-source heat pump is restricted by an outdoor control, and full back-up heating is used for heat the building or target. The cut-off temperature value can be determined by either a "low-temperature cut-off limit" of the heat pump equipment, or by an "economic cut-off temperature" that is determined by equipment efficiencies.
EER: Energy efficiency ratio. Used to indicate the cooling efficiency of a heat pump or air-conditioner at a particular operating point, expressed in BTU/h of cooling energy per Watt of electricity consumption. EERs vary with outdoor temperature.
EEV: Electronic expansion valve.
GSHP: Ground-source heat pumps also know as geothermal heat pump (GHP)
HDD: Heating degree day (HDD) is a measurement designed to quantify and compare the heating needs of buildings in different geographical areas. The HDDs for a location are calculated based on a comparison of the outdoor temperature for every hour in the heating season compared to a reference temperature above which heating is not required (generally 18°C in Canada).
HSPF: Heating Seasonal Performance Factor characterizes the average efficiency of an ASHP over a typical heating season. The HSPF is the ratio of BTUs of heating delivered to watt-hours of electricity consumed over the heating season. A higher HSPF rating indicates a higher efficiency. HSPF ratings for ASHPs vary by "Climate Zone".
HRAI: The Heating, Refrigeration and Air Conditioning Institute
HVAC: Heating, Ventilation and Air Conditioning.
kW: kilowatts, rate of energy use or transfer. Is used to rate electric power consumption of equipment, or the output capacity of heating or cooling equipment. One kW is equivalent to 3,412 BTU/h.
kWh: Energy consumption or thermal energy expressed in kilowatt-hours, equivalent to the amount of electricity consumed by a 1 kW load running continuously for one hour. One kWh is equivalent to 3,412 BTU.
SEER: Seasonal Energy Efficiency Ratio for electric cooling equipment over a typical cooling season. The SEER rating is the ratio of BTUs of cooling delivered to watt-hours of electricity consumed over the cooling season. A higher SEER rating indicates a higher efficiency.
Supplementary heating system: Heating system needed when the heat pump cannot provide enough heat to meet a building's heating load (e.g. furnace, electric baseboard, electric resistance heater, etc.)
TECA: Thermal Environmental Comfort Association
Thermal balance point: Outdoor temperature at which the heating load of the home just matches the heat pump's output capacity. Below the thermal balance point, the building heating load grows and the heat pump output declines sufficiently that the heat pump cannot meet the heating load without any support from a supplementary heating system.