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What is a heat pump water heater?

A heat pump water heater is like a reverse refrigerator. Here's a quick summary of what a heat pump water heater is, and how heat pump water heaters work.

There has been a noticeable hype around heat pumps. For instance, Elon Musk believes that heat pumps hold the key to a renewable energy-dominant future. Water heaters that use heat pumps (heat pump water heaters) have also witnessed sudden popularity. Here’s all the basics you need to know about them. 

What are heat pumps?

Heat pumps are devices that move heat. They use some energy (usually electricity) to move heat from one place to another. 

Imagine two rooms. Room A is hot. Room B is cold. If there was a heat pump between the two units, it would move heat from Room A to Room B. Room A would become cooler, while Room B would become hotter. 

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What are heat pump water heaters?

Heat pump water heaters use heat pump technology to heat water.

Regular water heaters would generate heat: by combusting a fuel (natural gas/propane) to light a flame that heats cold water, or by making an electric resistance coil hot with electricity.  

On the other hand, heat pump water heaters do not generate any heat. Instead, they move pre-existing heat from another source (like surrounding air) to cold water. Since they do not generate any heat, they typically use far lesser energy.

What is an air source heat pump water heater?

An air source heat pump water heater moves heat from surrounding air to cold water.  As a result, the surrounding air gets cooler while the water gets hotter. 

How do heat pumps work? Heat pump water heaters working:

As mentioned earlier, heat pump water heaters move heat from one source to cold water. How is heat moved though? Let’s look at how an air source heat pump water heater works

  1.  Air is blown by a fan into the heat pump unit. 
  2. Heat pumps consist of a refrigerant liquid. Refrigerant liquids are super sensitive to heat. So, the warmth in the blown air heats this refrigerant liquid. 
  3. The refrigerant liquid turns into gas as it becomes hotter. 
  4. This gas is passed through a compressor. Compressors increase the gas’ pressure. When a gas’ pressure is increased, it becomes hotter. 
  5. This hot gas is used to heat a substance that can hold this heat. For heat pump water heaters with storage, a large tank of water is kept hot with the use of this hot gas. 
  6. For tankless heat pump water heaters like Intellihot’s Electron series, the heat from this hot gas is stored in a thermal battery, ready to heat cold water every time hot water is needed. 

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With Real-World Dos & Don'ts