I would also like to be able to offer the option for people to be able to pay for heat with the other payments. I've been asking for it through resolutions or paypal/venmo. This time of year, it takes time to heat up and I wouldn't heat for people unless they pay 24+ hours in advance. It wouldn't be up to temp. It does cost me what they give me to heat it. It's 60+ a day if you break it down. For a longer stay, the biggest cost is upfront, the daily cost would be less, but it depends on usage. I've had people use 30 a day in spa heat - simply because they never shut it off. On a short stay, I lose money on pool/spa heat.