if i can add propane heater to spa

[r3206]

hi everyone, my pool has just been completed. long and exhausting almost 8 months.
we live in Central Florida and had a heat pump installed, I was told that it could be used for pool and spa and only take like 45mins to heat spa up.
we its been chilly here recently the lowes in 40's sometime alittle lower, we have turn on spa heater and it takes quite some time to heat, then after we use it, if we turn off spa, the overflow starts circulation and any warm water is lost in overflow to pool, next time we have to do it all again.
I am disappointed in how long it takes to heat, and we used to have a propane heater at last house, which was great.
we already have a large propane tank installed at house, we have gas dryer, gas stove top, and water heater.
my question is ..can I install a gas propane heater now after the build, would that be more efficient to heat spa up, then using the heat pump? or should I just try heat pump out for a while?
spa is a 7 foot round
pool is 16x32 4 to 7 foot deep
heat pump pentair ut 140
thanks for any suggestions

 

[cowboycasey]

Is it a natural gas dryer, gas stove top, and water heater or propane? if LPG it will be cheaper but a propane will be more expensive.... A heat pump is really designed to keep water at a certain temp not to get it there fast like you saw..

If you get a nat gas or propane heater get the biggest one you can..

 

[r3206]

i have propane in house so I guess I could get it hooked up to spa.

 

[jseyfert3]

my question is ..can I install a gas propane heater now after the build, would that be more efficient to heat spa up, then using the heat pump? or should I just try heat pump out for a while?

Faster? If you get a big one undoubtedly. More efficient? Depends on your definition of efficiency. If you’re talking cost to heat, then maybe propane would be cheaper when your ambient temps drop this low. Any other time of the year? Heat pump, though slower, is almost certainly going to be cheaper to operate.

 

[jseyfert3]

Yeah just confirmed my suspicions using Pentair's calculator. It's designed to calculate savings of heat pump vs gas for maintaining temp continuously, but roughly speaking would apply on average for heating a spa for occasional use as well. Basically if the heat pump lists a savings, then it's cheaper. For this example I just popped in a small 9000 gallon pool, set the water temp to 85 and used default electric for your area. It shows savings for heat pumps for a Jan-Feb swim season.


If you want to play with this at all and type in your exact electric and propane costs, here's the link. Note there are 0.915 therms per gallon of propane, so for price per therm take the $/gal of propane and divide that by 0.915 to get $/therm. For example, if you pay $2/gal of propane, then divide 2 by 0.915 to get $2.19/therm for your gas costs. The summary though is that it appears 40's are fairly abnormal temps for you? So I'm not seeing any way a propane heater would be cheaper. Faster yes, you could get a big heater. But not cheaper.

Natural gas? Well our cost up here is $0.59/therm, which is a lot cheaper that my example for $2/gal propane. If I try that example then gas wins out in cost in all but the summer months. But I suspect you don't have access to natural gas if you have propane.

Also note that the heat pump heating times will decrease somewhat as the ambient temps increase and the heat pump becomes more efficient.

 

[r3206]

thank you, I was just worried that if I decided I wanted to jump in spa I would have to wait hours before it was hot. Florida doesn't stay cold for long, so I'll see how the heat pump works, especially when Temps warm up

 

[Bradenpool]

What did you end up doing? We are in a similar situation...putting in a pool and spa with a heat pump in Sarasota, but concerned we will need a second heat source for the spa. We don't have natural gas and would have to put in a propane tank....the tank alone is $5500. Ugh. Wondering if we can get by with the heat pump, but afraid it's not going to be enough when we want to use the spa during the cooler months.

 

[PoolGate]

If you want the spa for hot heat like 110 a heat pump isn't going to cut it, especially with colder outdoor temps. With a spa you really have no option but fossil fuels for heat. Bigger the better.