You forgot to mention the brand you are looking at. The brand isn't as important as will it do the job you want it to. Alot of people think it's romantic to have one big enough for two. That wares out pretty fast and the cost of hot water, I suggest the number of gallons of water is a good place to start. If what you are looking at is available in meny place, go ask them all about any complaints they have had. Measure twice before you order.