Quote Originally Posted by waterbear View Post
If you are going with a spillover type of spa then it will basically stay at pool temperature and will have to be heated before use so you will need a heater with fast recovery time on the spa.
The heater you choose has to be balanced between differing objectives: equipment cost, available electrical capacity currently servicing your home (if you're using an electric heater or heat pump), fuel cost, and how quickly you need to have your pool or spa heated up. We chose a heat pump for fuel efficiency and low fuel cost in exchange for longer spa/pool heating times. Even still, our spa, which is right now about 78 degrees, is comfortable in 30 minutes at around 84 degrees, and hot within 90-120 minutes of turning on the heat pump. With just a little foresight, you can enjoy a heated spa on the cheap. It costs me 60 cents an hour to run my heat pump, so for $1.20, I have a hot spa for an evening's relaxation.