Quote Originally Posted by Tony G View Post

I was veering towards a heat pump, but as they take longer to warm up,
Don't really know where you got that info. from ???
It totally depends on the BTU output of the device !!!
Our 120K BTU heatpump pool heater will raise a ( 30 x 15 ) pool 15f in about 6 hours at about 1/4 the relative cost electricity / gas &, despite rumours to the contrary, works down to 45f.
To reap any benefit from a gas heater, you'd have to be on mains gas (not delivered propane which could run out during a guest's stay).
Do bear in mind that either device will only function whilst the pool pump is in operation....