What is the difference between a heat pump and a condensing boiler?

The difference between a condensing boiler and a heat pump lies in how the heat is produced: the boiler, at most, can supply as much heat as the quantity and calorific value of the fuel allows. The heat pump, on the other hand, has no such limits in relation to the energy input. A good heat pump can obtain a lot of ambient heat with little motive power (electricity): up to 5 kWh of thermal energy can be produced from 1 kWh of electrical energy.
The heat pump also does not use fossil fuels and does not emit combustion gases into the environment.
In addition to heating when it is cold, the heat pump is reversible and can be used to cool rooms when it is hot.