Another heat pump question - heating speed for hot tub

[kcautodoc]

Hey all, I'm wondering about what size of heat pump to get and how fast I can expect the hot tub section of the pool to be heated.

I am in Gulf Coast North Florida with 25,000 gal pool and a hot tub that is about 600 gal of that 25,000. We have a pool on the north side of the house and a pool cover enclosure as well. No solar cover yet but plan on getting something soon. The local shop is pushing the Nirvana E140 heat pump and there is not a bunch of info or reviews about it. Question one, in the late summer or early winter, with ambient temps in the 60's, how quickly can I expect a heat pump to heat the 600 gal hot tub into the mid 80's or higher? What about in the with ambient temps in the 70's? How high can I expect to get water temps in general? Is it a pipe dream to think that I can get mid to high 90's in the hot tub? If I can, during what kind of season can I achieve this? Does anyone have experience with Nirvana brand heat pumps and what brands / size would be recommended for this size pool?

Lots of questions but I think most of them are along the same topic.

Thanks,
Richard

 

[jblizzle]

Welcome to TFP!!

I don't think a heat pump is the right tool for the job you are trying to accomplish ... although curious to see others feedback.

 

[ps0303]

jbizzle is right. A heat pump is not tool for the job when the temps are in the 60's and 70's. I think you have a big pipe dream to think you can get that kind of heat you are looking for. Especially if you think you can turn it on and under 20 minutes have a hot spa to soak in.

GAS is the way to heat that spa.

 

[kcautodoc]

I am thinking an ambient air temp of 65-70 with a pool water temp of 75-80 since the pump would be running anyway. If I then switch to heat a 600 gallons spa only with a 140,000 btu pool heater you don't think I'd be able to break 100 after a few hours? The calculations say yes but of course this does not take into account any heat loss.

I am certainly not thinking under twenty minutes. I am thinking 2 hours or so. Turn the heat to the spa, cook some dinner, get the kids to bed and enjoy the hot tub after. Using the pool is an almost daily occurrence but using the hot tub is much less often.

 

[JasonLion]

Yes, that is possible. It isn't very efficient, but it can work. The extra time to heat the water will cause the heat lost to the environment to be much higher, canceling out any cost advantage a heat pump has over gas heat. So it will take longer to heat the water, and cost more both up front and when you use it, but it should work.