Cost of Pool heating

Your best solution is a Heat pump but make sure it is sufficiently calibrated for your pool. The cost depends on its size (capacity and how much heated pool you need per year and how many days ea. week and what water temp. you cannot do without.
Our big heat pump burns 3,5 KW/hr.  If you want it still cheaper reduce the water level to as little as 90 cm in the colder months to suffice for your daily workout.

Better still if you practice swimming in 17 - 20 °C water for 20-30  mins. and then hot shower to warm up again. Its hard but possible. The Finns and the Wodkaseniors even jump into ice water!!! Very good for the brave.

Thank You very much for your reply, Best regards