Chances are you’ve heard the phrase “heat pump” more than once if you’re in the market for a new HVAC system, looking to save on your energy bills or are environmentally conscious. But the name alone barely tells you anything about what they do or why they’re popular.
However, what’s clear is that more and more people are turning to heat pumps as alternatives to traditional heating and cooling units. They’ve been on the rise especially over the last decade or so, in part because, as the technology behind them improves heat pumps are becoming even more energy-efficient and cost-effective.
So what exactly is a heat pump? Essentially, it’s a machine that pulls heat from one area and puts it in another. In the winter, it takes from outside and puts it in your home. In the summer, it pulls the heat from the house and moves it outside.
How does it work, and how does it save money on energy bills? Let’s take a look.
Heat pumps work by creating heat exchanges inside and outside the home. The key to this is a refrigerant liquid that continually moves through the system without ever leaving it. It cycles through tubes in the system, continually warming and evaporating, and then cooling and condensing. This helps create a loop of heat exchanges.
A few important concepts are at play. First, heat always moves to cooler areas. Second, the refrigerant has a lower boiling point than most other liquids. Finally, adding pressure to a liquid decreases its boiling point and, as a result, increases its temperature.
In cold weather, then, any heat that’s outside the home moves naturally toward the cold refrigerant liquid. There, a compressor adds pressure to the liquid, lowering its boiling point. As a result, the heat boils the refrigerant quickly.
Now a gas, the heated refrigerant travels through the system. It reaches a heat exchanger that extracts the heat and uses it to heat the home. How it provides warmth, exactly, depends on the type of pump — more on that in a moment.
Meanwhile, the refrigerant condenses back into a liquid now that the heat is removed from it. It then travels back to the beginning to where it started and attracts more heat. This starts the cycle again.
To cool a home, the system works in reverse. The refrigerant absorbs heat from inside the home, causing it to evaporate and travel through the system. It reaches a reversing valve, where a change in pressure allows it to condense.
The heat that’s released during the condensing phase is sent outside the home, leaving cooler air inside the house. Meanwhile, heat that’s still in the house is once again attracted to the now-condensed refrigerant, continuing the cycle.
The three most popular kinds of heat pumps are air, water and geothermal pumps. Each use similar methods of transferring the heat. They differ in where they get their heat and how they use it once it’s in the home.
With an air-source heat pump, the heat is drawn from the air outside your home. From there, an air-to-air pump distributes the heat via fans that usually circulate the air through ducts.
An air-to-water pump uses the heat to warm a water tank. The hot water is then used for radiators and hot water throughout your home.
Geothermal heat pumps, or ground pumps, work differently in that they don’t attract heat from the air to the refrigerant liquid. Instead, warmth is sourced from under the ground. Here, the tubes containing refrigerant are laid sometimes up to 100 meters below the surface. The heat, as before, moves to the refrigerant to begin the cycle.
Heat pumps use less energy than traditional HVAC systems since they only need to move heat rather than create it. Systems like furnaces and radiators use gas or electricity to power coils that do heavy-duty work generating heat to warm your air and water. That’s the bulk of the energy they use.
Heat pumps however, just need enough energy to run the fans and compressors. From there, they draw in heat that already exists. That means they cost less money to run. According to the Department of Energy, a heat pump can up to 50 percent less to run than furnaces or baseboard heat.
Heat Pumps are also effective at taking care of a cold, or hot spot in the house. Sometimes there is a room in the house, often a bedroom, addition or basement, that won't stay the same temperature as the rest of the house. The addition of a heat pump can not only make the room comfortable, but also potentially lower your energy bills with this supplement.
What’s more, the technology is always getting better. The average heat pump lasts ten or 15 years, and new models are more and more efficient. Heat pumps on the market today are 20 percent more efficient than those sold a decade or two ago. Heat pumps are an effective, sustainable way to keep a home warm in the winter and cool in the summer with lower energy bills and less impact on the environment!