Suq Lee, a swimming pool heater will use electricity, which causes extra use of fossil fuels, solar pool heater takes energy from the sun which will heat the earth any way and put it in your pool. Massive difference if you care about the future.
A friend of mine installed tubes under his slate roof which water ran through into his swimming pool, but it got too hot in summer. I don't get this heated swimming pool idea at all, i swim to cool down. Heated swimming pools breed microbes and the bad guys are not kept in check by the good guys like in a natural situation, people sweating in your warm swimming pool, swimming in each other peoples sweat, kids wee and saliva, it doesn't matter they tell me the chemicals will kill the microbes. But chlorine stinks and pricks my eyes, and still you swim in other peoples dead skin particles, snot , dandruff and sun lotion flowing on top. It just doesn't appeal to me, but have fun folks, you're not harming me.
Why not make a
natural swimming pool? No chlorine needed, the plants break down waste, you create a biotope for frogs, insects and animals eating snails, you can have flowers growing in your swimming pool.
People take existing swimming pools and convert them into their own paradises which help birds insects and wildlife.