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How Does a Heat Pump Work in the Winter?

How Does a Heat Pump Work in the Winter?

January 05, 2021

Many people in Georgia enjoy the cool flow of air provided by heat pumps in the warm weather. These efficient cooling machines do not lose their usefulness once summer ends. They can do double duty as a heater in the winter too. The same technology that extracts heat from your indoor air in the summer can achieve heating in the winter. A heat pump simply reverses its function and draws heat energy from the outdoor air and delivers it inside your house in the winter. Let’s take a closer look at how a heat pump works in winter and its optimal range of operation.

Optimal Heating Range of Heat Pumps

You may find it difficult to believe that outdoor air in the winter has any heat energy to offer, but it does. As long as the refrigerant moving through a heat pump can be cooled to a temperature below the outdoor air temperature, it can pick up heat from the external air.

Of course, this technology can reach a point of diminishing returns. The energy efficiency that has made heat pumps popular only continues when outdoor temperatures are above 30 degrees Fahrenheit. Once temperatures drop below that 30-degree mark, a unit will work harder and consume more electricity. At the same time, the machine’s capacity to heat your home begins to drop.

Anatomy of a Heat Pump
  • Outdoor Unit
  • Indoor Unit
  • Compressor
  • Reversing Valve
  • Expansion Valve

Heat Transfer Process

The parts of the heat pump work together to warm your home in the winter. Unlike a furnace, a heat pump does not burn any fuel when producing heat. This is why this technology is so energy efficient for heating purposes.

The system moves refrigerant between the outdoor unit and the indoor unit. When you set a unit on the heating mode in the winter, the coil within the outdoor unit becomes an evaporator. The fan inside the outdoor unit blows air over the evaporator coil. At the same time, the unit has released the pressure on the refrigerant, which reduces the temperature of the substance. The expansion valve governs this function. The heat pump moves this cold, low-pressure refrigerant into the outdoor coil where it can pick up heat energy from the air.

Next, the compressor applies pressure to the refrigerant as the heat pump moves it into the condenser coil in the indoor unit. A fan in the indoor unit blows across this coil that has been warmed by the pressurized refrigerant that picked up the heat while moving through the outdoor unit. The blower draws the warmth from the coil and sends it into your home.

The refrigerants used within modern heat pumps are blends of chemicals that can shift between liquid and gaseous states with only a small input of energy. The current refrigerant blend called R410A is most in use today. It is meant to replace previous refrigerants that had toxic attributes.

The heat exchange achieved by heat pumps relies entirely on the refrigerant contained within its system. As long as a unit is not leaking, the refrigerant can perform well for many years. The part within the unit called the reversing valve manages the switch between heating and cooling modes. A unit that you used during the hot season to cool your home can be switched into a heating mode in the fall. When you do this, the reversing valve redirects the processing of the refrigerant within the machine.

Heat Pumps Work in Georgia’s Climate

Overall, Georgia is a state with a climate well suited to heating with a heat pump. As already noted, heat pumps perform efficiently as heaters down to 30 degrees. Coastal Georgia might only experience 10 days of freezing temperatures on an average year. The northern part of the state, particularly at higher elevations, can have up to 110 days of temperatures around the freezing mark. Even so, the average winter low temperatures throughout the state tend to stay in the forties.

What all of this means is that a heat pump could satisfy all of your heating needs if you live in this climate. The extremely low temperatures that reduce heat pump efficiency will either not happen or only occur rarely.

Heat Pumps and Supplemental Heat Sources

Adding a heat pump to your home does not stop you from using an alternative heat source for the times when winter might get really cold. Many homes that rely on heat pumps for the majority of their heating needs also have gas or electric furnaces that activate when a heat pump ceases to be the best heating option.

You might also hear the supplemental heater referred to an emergency or auxiliary heat. Some thermostats automatically manage the switching between the two heat sources depending on outdoor temperatures. You also have the option to manually switch on emergency heat if your heat pump breaks down and requires repairs.

A hybrid heating system that uses both a heat pump and furnace offers you the best of both worlds. You save on utility costs by using the heat pump when the weather is above 30 degrees because heat pumps work best as heaters between 30 and 60 degrees. If a cold snap strikes, then you can switch to heating with a furnace, which performs best at colder temperatures because it actually creates heat.

Heat pumps in mild climates provide their owners with great value because the unit can serve heating and cooling needs 12 months of the year. Depending on your regional climate, you may not need to invest in a furnace at all if you never expect prolonged freezing temperatures that a heat pump cannot handle. For those who choose a hybrid approach to heat with both the heat pump and furnace, utility costs will remain low as long as both units are used within their optimal temperature ranges.

Relying on a heat pump through most of the winter also reduces wear and tear on a furnace. This will delay the need to repair or replace a furnace when it only runs as a supplemental system.

The technicians at Bardi Heating, Cooling & Plumbing in Norcross, GA, can answer your questions about how to heat your home efficiently. We’re a Carrier Premier Dealer with access to top-of-the-line modern heat pumps. We can install a new heat pump that keeps your home comfortable in the winter.

Trusted Provider of Heating, Cooling, and Plumbing Services

Since 1989, Bardi Heating, Cooling & Plumbing has been responding to repair calls from local homeowners. We can fix or replace water heaters, clear blocked drains, and repair air conditioners and furnaces. When you want to upgrade your home, our licensed technicians can install a modern and efficient heating and cooling system. Every year thereafter, you can count on our maintenance technicians to protect your investment whenever you require a tune-up. Learn how we can help you live more comfortably by contacting us today.