How Does A Heat Pump Work In Winter?

Presidential Heating & Air Conditioning

Gaithersburg HVAC Contractors


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Heat pumps are a great way to save money on your heating costs during the winter because they can efficiently heat your home without using natural gas. They work like an air conditioner in reverse. In this article you will learn how does a heat pump work in the winter.

An air conditioner works by absorbing heat from the air inside your home and releasing it outside. A heat pump does the opposite: it absorbs heat from the air outside and releases it inside. Heat pumps rely on refrigerants to do this.

How Does Heat Pump Work In Winter Months

heat pump outside home during the winter, that saves heating costsHeat pumps work by using a refrigerant that absorbs heat by evaporating at low pressure. The heated air is then pumped to a different coil in the system, where it’s compressed and condensed at a high pressure, releasing the heat that is absorbed in the first coil. This cycle is fully reversible, so a heat pump is capable of cooling your home in summer and warming it in winter. Some heat pumps, called air-source heat pumps, absorb heat from the air outside in winter to release it into your home. In the summer, the pump releases the heated air outside. This is the most common type of heat pump. Other pumps, called ground-source heat pumps, draw heat from the ground or from groundwater.

Can Heat Pumps Work in Winter?

Surprisingly, heat pumps can work even on very cold winter days. That is because even on cold days, there is still heat in the air and ground. Even when the temperature outside is 0 degrees, the air still has about 85 percent of the heat that it has at 70 degrees. In cold weather, the refrigerant is pressurized and condensed as it flows into the coil in the outside unit. Then, the pressure is lowered and it begins to evaporate, a process that naturally absorbs heat from the surrounding environment. As the heated air is pumped back into the coil on the inside unit, it is condensed again, releasing the heat that was absorbed in the outside coil. Fans move air over both coils to facilitate the heat transfer.

Heat pumps leverage the fact that heat always flows to areas of lower heat. Heat pumps also leverage cold air because they simply utilize energy, which is a measurement of the molecules and atoms of any substance. For this reason, cold air contains less energy or heat than something that is hot.

Additionally, heat pumps also take advantage of the way pressure affects the ability of certain substances to absorb heat. Because refrigerants use very low freezing points, keeping this substance in a liquid form requires high pressure. So, even when exposed to cold weather, if the pressure is not maintained, they evaporate, which is a process that always absorbs energy in the form of heat from the surrounding air.

It is normal in winter to see frost or even light amounts of ice on the evaporator coil outside. The coil removes heat from the local air, which means the air immediately around the coils is unusually cold. The water in it is likely to freeze. If the whole unit is encased in ice, however, that is a problem.

man installing a heat pump before the winter monthsNormally, a heat pump goes through periodic defrosting cycles to ensure that it does not freeze over completely. In these cycles, the pump is essentially in air conditioning mode, releasing heat through the external coils instead of absorbing it. The outdoor fan will shut off, too, which allows the coils to become very warm, melting the ice. A thermostat in the outdoor unit will detect when the ice has completely melted, and it will automatically cause the pump to switch back into heating mode.

The entire process takes less than ten minutes and often as little as two minutes, depending on how much ice has formed on the coil. It works quickly enough that there should be no significant cooling inside the house.

If a heat pump freezes over and is encased in ice, it is likely that something has gone wrong with the sensors that control the defrost cycles.

If you are wondering what the differences between a heat pump and an air conditioner are, the main difference is that an air conditioner can only remove heat from the home. It is incapable of heating the home during the winter, and it is usually paired with a furnace. Heat pumps are able to do both.

Heat Pump Advantages

Heat pumps offer a number of advantages over traditional furnaces. First, they are much more efficient than furnaces. This means that a heat pump can save you a lot of money each year. But it also means that it will heat your home more quickly and keep it warm more efficiently. Heat pumps are also easier to maintain than a furnace. Since many furnaces involve combustion, they have to be regularly cleaned and maintained properly to keep them safe. A heat pump does not burn anything, and so it has very low maintenance costs. In fact, much of the regular maintenance that needs to be done can be handled by the homeowner.

heat pump outside house with cooling systemThe biggest advantage over an air conditioner is that the heat pump is an all-in-one heating and cooling system. While operating in cooling mode, a heat pump is no different from an air conditioner. They work in exactly the same way. A heat pump is essentially an air conditioner with a reverse valve and a few extra sensors, while an air conditioner is essentially a one-way heat pump. If you have an air conditioner, you will need to buy a separate heating system, such as a furnace. If, on the other hand, you buy a heat pump, you will have one system to handle your heating and cooling needs.

If you have any more questions, or if you would like to schedule a consultation regarding a heat pump installation or replacement, contact us at Presidential Heating and Air. Our experts are ready and waiting to speak with you.

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