Heat pumps are not new to the market but the price of fossil fuels has made them a lot more attractive. Also, as technology has improved, their operating cost has dropped dramatically leading to higher levels of efficiency.
What is efficiency? How do they work? When should you invest in one instead of a gas or solar system? What does it cost to run? These and some other questions are considered here so read on.
The efficiency which is talked about in relation to electric heat pumps is also called Coefficient Of Performance or COP. This gives a relation between the amount of energy used to the amount of energy produced.
To compare apples with apples, a common electric immersion heater (such as in a kettle) is around 90% efficient so would have a COP close to 1 but heat pumps can be rated with a COP of 5 which means an efficiency of 500%. This is because heat pumps don't actually create heat (like an immersion heater does) they just move it from one place to another.
This is something the prospective purchaser must be aware of because heat pumps have a drawback. Electric heat pumps take heat from the air and transfer it to the pool water so as the air temperature drops so does their efficiency. In fact, once the air temperature hits around the 45 degrees F mark, they stop working and can even freeze up!
When comparing different brands for efficiency it is very important to make sure the COP is calculated under the same conditions for each pump.