How do heat pumps work

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How do heat pumps work and why are the energy efficient?

Edit: the question is sufficiently answered. Thanks guys!

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Heat pumps work the same way as any air conditioners. They use atmosphere to boil a liquid into a gas, putting heat in the gas, then they compress the gas to recondense the gas into a liquid, discharging the heat in a different place.

I don’t know that there’s an eli5 way to describe how a heat pump is more efficient than traditional electric heaters that use electricity to heat coils, but the reason they’re in the news is that they’re a viable electric alternative to standard natural gas furnaces, which means that they can be run on power from solar, wind, and other renewables, where natural gas furnaces will always be run on fossil fuels, so they’re the best carbon neutral way to heat a home (at least potentially, depending on how electricity is generated).

Heat pumps are not energy effecient, just like any pump they require an input of energy.

There are several types of heat pumps, but an air conditioner is an example of a heat pump most people are familiar with. The purpose of a heat pump is to move heat against the concentration gradient. This means taking heat from your house and pumping it outside, even though the outside is hotter than your house. This is accomplished by using a condenser, which takes a gas and compresses it into a liquid (in this case its a special chemical called a coolant). After the coolant is liquified, it is allowed to expand. The expansion of a gas results in its temperature dropping significantly, so now we have cold coolant. The coolant is pushed through a long thin tube, and air from your house is blown across the tube. The warmer house air gives heat to the coolant, and the house air is cooled off. Repeat the cycle, and you have a heat pump!

A heat pump moves the heat that exists in a large area outside into a small area inside. It’s efficient because it’s not using energy to generate heat, just to move that existing heat.

Heatpumps do not work the same as other heating units. They cool the same way but they heat by concentrating existing heat (energy) in the air and pumping it into your home. This is why you need a secondary heat furnace or strip when the temp gets below 40f or so bc it cannot concentrate the heat enough to warm the house to above 65f or so at that point.