Which refrigerant does a heat pump use? Types explained

What does a heat pump refrigerant do?

A heat pump moves heat with a refrigerant that circulates through the compressor, the outdoor coil, an expansion device and the indoor coil. The fluid boils at a low temperature, so it picks up heat from outdoor air even when the air is cold, then releases that heat indoors when the compressor squeezes it into a hot, high-pressure gas. The loop and its sealed pipes are the same idea whether the unit heats air or water, and the guide to how ground-source heat pumps work shows the cycle with a ground loop in place of the outdoor coil.

The choice of refrigerant sets the operating pressures, the efficiency at different temperatures, the safety class and the environmental impact of any leak.

What are the main refrigerant types?

• R-410A. A blend used in most residential heat pumps and air conditioners installed for years. It is non-flammable and efficient, but its global warming potential, or GWP, is high, at roughly two thousand times that of carbon dioxide over a century.
• R-32. A single-component refrigerant with roughly one third of the GWP of R-410A. It is mildly flammable, rated A2L, and common in newer equipment, especially ductless units.
• R-454B. A blend also rated A2L with a GWP well under that of R-410A. Many ducted systems are moving toward it.
• R-290 (propane). A natural refrigerant with a GWP of about three. It is flammable, so charges are small and used in compact systems.
• R-744 (carbon dioxide). A natural refrigerant with a GWP of one. It works at high pressure and suits some water heating products.

Older equipment may still contain R-22, which has been phased out for ozone-layer reasons, and R-134a appears in some other appliances.

Why is the industry changing refrigerants?

Hydrofluorocarbon refrigerants such as R-410A trap far more heat than carbon dioxide if they leak. Canada, like many countries, has committed to reducing their use through an international agreement, and the rules on manufacture, import and equipment are tightening in steps. The exact limits and dates change, so check the current rules with Environment and Climate Change Canada and with your provincial authority.

For a homeowner the practical effect is gradual. New equipment arrives with lower-GWP refrigerants, and the cost and supply of older ones change as the phase-down continues.

What does a refrigerant mean for repairs and safety?

Refrigerant work, such as charging, recovery and leak repair, needs a certified technician because the fluid is under pressure and the law restricts venting it. A lower-flammability class does not make it a do-it-yourself job. The A2L refrigerants burn only under narrow conditions, and the equipment is designed with sensors and installation rules to handle that, so installers follow the manufacturer's manual closely.

If your system is old, ask what refrigerant it holds and whether it can still be serviced economically. A leak in an aging unit is a typical trigger in the heat pump repair-or-replace decision. Routine checks, including a look for oil stains and low-capacity signs, are in the heat pump maintenance checklist, and the typical visit is described in heat pump servicing cost and schedule.

Should the refrigerant affect your purchase?

It is one factor among many. Sizing, cold-weather output, the installer's quality and the warranty usually matter more to comfort and cost. Still, it is reasonable to ask which refrigerant the quoted model uses and whether the installer is trained on it. Put that next to price and warranty in the heat pump quote comparison.

A model built for a lower-GWP refrigerant is more likely to stay supported as the transition continues. Equipment that uses a phased-out fluid can face higher service costs later, so factor in the likely service life.

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