Glossary of Terms

Air Changes Per Hour at 50 Pascals (ACH50): The number of times per hour the entire heated volume of air in a house is replaced when the building envelope is subjected to an interior-exterior pressure differential of 50 pascals (Pa).

Airtightness Test: A test method to measure the air leakage of the building under the test conditions.

Airtightness Testing: A test to determine how airtight the building envelope of a home or building is. Several common units of measurement include air change per hour (ACH), Equivalent Leakage Area (ELA) and Normalized Leakage Area (NLA). 

Annual Fuel Utilization Efficiency (AFUE) Gas Furnace or Boiler Efficiency: A standardized metric, as a percentage, used to express thermal efficiency during the heating season typically for gas- and oil-fired furnaces and boilers taking into consideration normal operating losses (e.g. standby, cycling) and accounting for the fact that most heating systems rarely run long enough to reach their steady-state efficiency, particularly during the shoulder months.

Blower Door: The equipment used to perform an airtightness test. This includes a fan, door frame, frame cloth and manometer (pressure gauge).

Blower Door Tests: Various tests using the blower door equipment that may be required for air tightness testing.

Building Envelope: The components of a home that enclose the conditioned (heated and cooled) space. This includes the foundation/floor, ceiling, walls, windows and doors.

Coefficient of Performance (COP) Heat Pump (And Air Conditioning for Cooling) Heating and Cooling Efficiency: A ratio between the rate at which the heat pump transfers thermal energy and the electrical power it consumes. This provides an indication of how much space heating or cooling the heat pump provides for every unit of electricity it consumes. A higher COP results in the heat pump consuming less electricity for a given heating or cooling load.

Design Cooling Load: The total heat gains in the house including solar gains and internal gains associated with occupant load and base loads, when the outside temperature is at the summer design temperature on a clear July 21st. It represents the predicted capacity of the cooling system required to maintain the home at the design temperature of 24 °C (75.2 °F) in the summer.

Design Heating Load: The total heat loss from the house when the outside temperature is at the winter design outdoor temperature without any solar or internal gains on a clear January 21st. It represents the predicted capacity of the heating system required to maintain the home at the design indoor temperature of 22 °C (71.6 °F) in the winter.

Effective Thermal Resistance:
The combined resistance to heat flow of all the elements of a given assembly (e.g. insulation, framing members) measured in RSI/R-values.

Energy: A quantitative property that describes the capacity of a body, object or system to do work. Common units of energy include gigajoules and kilowatt hour. When we heat our homes, we are converting energy from a fuel source or generation process (think hydro-electric) into heat.

EnerGuide Rating: The energy performance rating of the house, stated in gigajoules per year, determined using the standard operating conditions and calculated by subtracting the annual renewable energy contributions from the annual energy consumption.

Energy Advisor: An individual registered with Natural Resources Canada to deliver the EnerGuide Rating System Basic Service and additional services.

Energy Recovery ventilator (ERV): A balanced supply and exhaust ventilation system with a heat exchanger that uses exhaust air to preheat or precool incoming air and that captures the latent energy of the humidity in the air.

ENERGY STAR® Certified: Products that have been tested according to prescribed procedures and that meet strict technical specifications for energy performance.

Equivalent Leakage Area (ELA10) Reference to Air Tightness: The size of the hole, expressed in cm² or sq.in., through which would pass the same amount of air that passes through all of the air leakage holes in the building envelope at a pressure difference of 10 Pa.

Existing House: A house that is older than 6 months, based on the date of occupancy by the first homeowner

Furnace: An appliance which converts energy to heat by burning wood, gas or oil, or by converting electrical energy to heat. A furnace connected to a forced-air heating system uses a fan to distribute heated air via a central ductwork system to meet space conditioning needs.

Gigajoules (GJ): A unit of energy, equivalent to one billion joules, or 278 kWh. The NRCan EnerGuide rating system uses the Gigajoule to estimate the energy consumption of a home on an annual basis.

H2K: Abbreviation for HOT2000, the modelling software developed by NRCan used by registered Energy Advisors to calculate the estimated annual energy use of a home.

Heat Recovery Ventilator (HRV): A balanced supply and exhaust ventilation system with a heat exchanger that uses exhaust air to preheat or precool incoming air.

Heating Seasonal Performance Factor (HSPF, HSPF2) Heat Pump Efficiency: A measure of heating seasonal energy performance for heat pump equipment, which is climate-region specific. HSPF is a ratio of how much heating is delivered to the building over the full heating season, to the total electricity used to deliver the heating over the same period. 

HVAC: Acronym which stands for Heating, Ventilation and Air Conditioning.

Kilowatt Hour (kWh): A unit of energy, equivalent to 0.0036 GJ. Kilowatt hours are the common billing unit for electrical utilities, which show how much energy a household consumed over a given time period.

Multi-Unit Residential Building (MURB): A building that has two or more units fully or partially stacked, or joined by a common space if not stacked, that may consist of a combination of residential and non-residential occupancies.

MURB Single Unit: A single dwelling unit located within a MURB that meets the eligibility requirements.

Nominal Thermal Resistance Insulation Value: The rated thermal resistance to heat flow of a building product without taking into account how the assembly in which it is installed will impact its thermal resistance characteristics; measured in RSI/R-values.

Normalized Leakage Area (NLA10) Reference to Air Tightness: The ratio of the equivalent leakage area at 10 pascals (ELA10) to the area of the building envelope, where the area of the building envelope is defined as all above- and below-grade floors, walls (including doors and windows) and ceilings (flat or sloping) that are correspondingly below, above and adjacent to unheated spaces and spaces heated to less than 10 °C (50 °F), and are based on interior dimensions; expressed in cm²/m² or sq.in./sq.ft..

Normalized Leakage Rate at 50 Pascals (NLR50) Reference to Air Tightness: The quantity of air that leaks into or out of the building per hour, divided by the total envelope surface area (in m² or ft²) at a differential pressure of 50 Pa, where total envelope surface area is defined as all above- and below-grade floors, walls (including doors and windows) and ceilings (flat or sloping), and are based on interior dimensions; expressed in L/s • m² at 50Pa or CFM/ft² at 50 Pa. 
NOTE: All surfaces (walls, ceilings, floors) which are common with another heated unit are included in the total envelope surface area.

NRCan: Abbreviation for Natural Resources Canada, the Government of Canada department which administers and oversees the EnerGuide for new and existing homes labelling program.

Occupant Comfort: A subjective experience that describes the level of satisfaction and well-being experienced by someone within a building or space. It encompasses various factors that contribute to a comfortable and healthy environment, including thermal comfort, lighting, air quality, acoustics, and overall spatial arrangement.

Part 9 Construction: That construction which falls under Part 9, Division B of the National Building Code of Canada (referenced by the provinces). This applies to all housing and small buildings that have a footprint less than 600m2 and are 3-storeys or less in height.

Power: The amount of energy expended over a given time period (the rate at which work is done). Common units of power include the watt, BTU/hr.

Rated Energy Intensity: A normalized performance metric calculated by dividing the rated annual energy consumption by the heated floor area.

Seasonal Energy Efficiency Ratio (SEER, SEER2) Heat Pump and Air Conditioning Cooling Efficiency: A measure of seasonal energy performance for cooling equipment. SEER is a ratio of how much cooling the heat pump or air conditioner produces over the full cooling season, to the total electricity used to deliver the cooling over the same period.

Secondary Suite: A self-contained dwelling unit located in a house where both dwelling units constitute a single real estate entity. In the case of a house with a secondary suite, the units may be fully or partially stacked, side-by-side or joined by a common space.

Steady State Efficiency (SS): The maximum efficiency of a heating appliance after it has been operating long enough to reach its peak operating temperature, measured to a standardized test procedure and expressed as a percentage.