Originally Posted by Pblais
Even that is not always true. It depends on the temperature difference between how cold it is and how much heat is gained. At low temperatures a heat pump fails to deliver affordable heat. That being the case it would better to say that a heat pump can be 3 times more cost effective under perfect circumstances.
In heat pump terminology, the difference (Delta T) between the temperatures where the heat is extracted (the air or ground/Water 'source'), and the temperature where the heat is delivered (the 'sink' - the boat cabin
or HWT); is called the “lift.”
The smaller the lift, the higher the efficiency will be.
Ideally, the heat source should be as warm and stable as possible during the heating
season, and the heat sink as cool as possible during the cooling
season (thus minimizing the Delta
That being the case, it would better to say, that a heat pump can be 3 (or more) times more cost effective under less extreme
circumstances, in which less heat transfer is required.
Thus, a Heat Pump makes excellent sense in a milder heating