How Does a Heat Pump Work?

Heat Pumps can offer significant advantages over standard heating and cooling systems – but how exactly do they work? And, is a heat pump the right choice for your home or commercial building?

Ask a group of individuals what they feel is the greatest invention in the last couple hundred years and you’ll likely get a wide variety of responses. One common answer to this question is: centralized heating and cooling. Think about it - there is nothing quite like the cool, crisp environment inside of an air-conditioned home in the dead of summer, or the toasty warmth of a centrally-heated house during the bleak winter months. With centralized heating and cooling being the norm in so many homes these days, it pays to have a basic understanding of how these systems work, what the maintenance requirements are, and which systems are the most efficient for your particular application. In this article, we will discuss the functionality and performance of a heat pump system – a common heating and cooling system that is found in homes throughout the world.

Heat Pumps are Efficient and Robust

A heat pump operates in a simple and efficient manner and is ideally suited for those who reside in moderate climates. A heat pump does one basic process extremely well – it transfers heat from one location to another, effectively cooling or heating a specific area to provide climate controlled comfort for the occupant. The chart below outlines the basic cycle that moves heat from inside the house to the outside world in order to cool the home, as well as the opposite process. Heat pumps are effective at harnessing heat from the ground or air to heat a home, and tend to use less energy to heat and cool a home when compared to a comparably-sized air conditioning unit and furnace.

Heat Pumps “Transfer” Heat, They Do Not Create Heat

A standard furnace uses a fuel source like natural gas to directly heat the air within the system. This air is then blown into the ductwork of a home and out through the heat registers in the house. This requires a fair amount of fuel – in this case natural gas, to heat an average-size home. A heat pump, on the other hand, simply moves heat from one place to another – heating the areas that need additional warmth, or cooling areas that are too warm to be considered comfortable for residents.

The typical heat pump is commonly known as an air-air pump, and it works by transferring heat from outdoor air and moving it into the ductwork within a home or building. The pump can then circulate warmer air throughout the structure to provide adequate heat. One big selling point of a heat pump versus an air conditioner and furnace configuration is that the heat pump can both heat and cool a home – all with one unit. In order to do so, the heat pump employs a key piece of equipment called a reversing valve. This valve effectively reverses the refrigerant flow within the system, allowing the heat pump to send hot air out of the home, and the refrigerant to continually cool the building.
It is important to note that heat pumps are generally most effective in climates that experience moderate temperature swings, otherwise a traditional forced air furnace and central air conditioning unit are best. Here is a diagram that shows the basic cycle of the heat pump, as it cools in the summer and warms in the winter:

One of the most important elements to keeping a heat pump-based system running at peak efficiency is ensuring that the filters are changed at appropriate intervals. Most experts agree that a once-per-month filter swap is ideal, though some tend to push that number to once per quarter. When it comes to keeping these finely tuned systems running well, it pays to err on the side of replacing the filters once per month – the payback will be enhanced system life and much more efficient operation.