The typical above-ground propane tank that I see installed at residences is 250 gallons. If you're going buried then you may have more flexibility on size. I would recommend you check out a heat pump though, they are quite efficient in central Texas and you won't have to deal with getting someone to come out and refill a tank. Plus I suspect that propane and natural gas will continue their price climb with oil prices, but electricity prices will hopefully moderate as our country moves towards alternative sources for electrical generation (solar, wind, geothermal, etc.)

Tresw - Thank you so much for the feedback. I know there is a major debate over the issue of propane/gas vs heat pump. You raised a good point on the electricity issue.
For a spa, what might be the average time to raise water from 70 to 100 degrees?

Any ideas on how long a 250 gallon propane tank would last for the occasional hot tub session? Thank you!

we have propane to heat our house so we just tapped into that to run the pool heat... its a 1000 gallon tank

id say it averages 10-15 minutes to get the spa from 70-100

it really doesnt use that much gas to run the hot tub... im guessing 250 gallons should last you all summer... when we opened the pool in may we were at about 65% full now we are around 60 and we had heated the pool a few times in the beginning and use the spa 4-5 times a week...

jfilaset - thank you so much for that info, that is great information. I appreciate you sharing!