Can You Add Freon to a Home Heat Pump Unit in the Winter?

Heat Pump Systems

• In many homes, heat pump systems coordinate both heating and cooling functions within a home’s heating and cooling system. For air conditioning purposes, a heat pump removes heat from the indoor air. For heating purposes, a heat pump moves heat from the outdoors to the indoors. In effect, a heat pump system runs in one direction in the summer months, and then reverses operations during the winter months. Freon acts as the lifeblood of a heat pump system, meaning low levels will cause a system to work at less than optimal energy efficiency.

Temperature Differences

• A heat pump system uses a specified amount of freon to heat or cool a home. When freon levels dip below a certain point, the system has to work harder to deliver the desired results. In the wintertime, heat pump systems use an outdoor condenser unit to pull heat from the outdoor air and absorb it into the freon liquid. This process relies on certain temperature fluctuations that change freon materials from gas to liquid forms. When recharging a system in the winter, a technician must ensure that the temperature levels in the refrigerant tank match those found in the condenser unit.

Coil Functions

• Heat pump systems operate off of coils that run between an outdoor condenser unit and an indoor air handler device. As heat pumps reverse operations in the winter months, the coils connecting the outdoor condenser to the indoor air handler unit perform opposite functions when compared to the summer months. Since the condenser unit removes heat from outdoor air during the winter -- as opposed to expelling heat into the outdoor air in the summer -- the coils must transfer the heat into the freon liquid as opposed to removing heat from the freon liquid. This means the heat pump system converts gases into liquid during the winter as opposed to converting liquid into gases during the summer.

Temperature Adjustments

• When exposed to cold winter air, a freon tank can undergo a cooling effect that makes it difficult to transfer freon materials into condenser unit coils. If freon materials become too cold, recharging the heat pump system can take considerably longer than normal. In effect, a drop in tank temperature means the air pressure inside the tank is lower than the air pressure inside the condenser coil. To avoid this problem, technicians compare temperature readings between the input coil and the freon materials. Often, under winter conditions, the freon tank will require warming so coolant materials can flow into the condenser unit.