Heat Pump FAQs

• Heating Mode: A heat pump extracts heat from the outside air (even in cold weather) and moves it indoors.
• Cooling Mode: It removes heat from indoors and releases it outside.

Heat pumps are efficient because they transfer heat instead of generating it. Key metrics include:

• COP: Compares heat transferred to electrical power input.
• EER: Cooling efficiency.
• HSPF: Heating efficiency over a season.
• SEER: Cooling efficiency over a season.

• Refrigerant: Absorbs, transports, and releases heat, changing phases (liquid, gas, vapor).
• Reversing Valve: Switches refrigerant flow between heating and cooling modes.
• Coils: Heat transfer between refrigerant and air.
• Evaporator: Where refrigerant absorbs heat indoors.
• Compressor: Compresses refrigerant, raising its temperature.
• Condenser: Releases heat outdoors.
• Expansion Device: Lowers refrigerant pressure and temperature.
• Outdoor Unit: Transfers heat to/from the outdoor air.
• Indoor Coil: Transfers heat to/from indoor air.
• Plenum: Distributes air in ducted systems.

1. Expansion Device: Low-pressure liquid turns into vapor.
2. Outdoor Coil (Evaporator): Absorbs outdoor heat.
3. Compressor: Compresses vapor, raising its temperature.
4. Indoor Coil (Condenser): Transfers heat indoors. As it gets colder outside, heat pumps lose efficiency and need supplemental heating.

1. Expansion Device: Low-pressure liquid turns into vapor.
2. Indoor Coil (Evaporator): Absorbs heat indoors.
3. Compressor: Compresses vapor, raising its temperature.
4. Outdoor Coil (Condenser): Releases heat outdoors. The system also dehumidifies air.

In cold weather, frost may build on the outdoor coil, reducing efficiency. The defrost cycle:

• Switches to cooling mode to melt frost.
• Turns off the outdoor fan to help melt frost faster.
• Uses demand-frost control (activates only when needed) or time-temperature defrost (set intervals).

Heat pumps require supplemental heat in very cold weather (usually below -15°C to -25°C).

• All Electric: Uses electric resistance elements or baseboards.
• Hybrid System: Combines a heat pump with a furnace or boiler for backup.

• Cooling SEER: Minimum 14, with a market range of 14-42.
• Heating HSPF: Minimum 7.1 (Region V, like Ottawa), with a range of 7.1-13.2.

• Single-Speed: Operates at a fixed capacity, meeting minimum efficiency standards.
• Variable-Speed: Adjusts capacity to match heating/cooling needs for better efficiency.
• Cold Climate Heat Pumps: Designed for colder areas, they have higher efficiency and better performance at low temperatures.

Heat pumps are verified by the Canadian Standards Association (CSA) for electrical safety and performance.

Proper sizing is crucial. A professional should calculate heating and cooling needs using a recognized method (e.g., CSA F280-12). An undersized system uses more supplemental heat, while an oversized system may cause inefficiency and discomfort.

• HSPF: Choose a high HSPF unit. Check its performance at -8.3°C.
• Defrost: Look for demand-defrost to minimize energy use.
• Sound Rating: A lower decibel rating means quieter operation (most units are ≤ 76 dB).

• Professional Installation: Ensure proper sizing, installation, and maintenance by a qualified contractor.
• Ductwork Modifications: Heat pumps require higher airflow, possibly needing duct adjustments.

• Set-points: Use a lower temperature for supplemental heating (2-3°C below the heat pump set-point).
• Defrost Efficiency: Turn off the indoor fan during defrost cycles to save energy.
• Setbacks: Avoid deep temperature setbacks. Use a "smart" thermostat for early recovery.
• Airflow & Fan Settings: Adjust airflow and fan settings for comfort (high fan for heating, low for cooling).

• Annual Maintenance: Schedule yearly checks with a professional.
• DIY Maintenance: Change filters every 3 months and ensure vents are not blocked