New heat pump. How much and which one is best?

[Arobeth]

Hello,

I am looking to put a heat pump on our pool, so we can use it all year around. I live in Florida (zip 33024) and even though the weather is nice outside the pool can be a little cool, specially for my wife.

My pool is rectangular (10,000 gallons) and do not have a cover. Would prefer not putting a cover for aesthetic reasons. It gets full sun from about 9:00 AM until sunset. We are planing to use it to heat the pool for some weekends only.

- On average, how much does is cost a heat pump (equipment + installation) for a pool this size?

- Any recommendations on brands/models?

- With a 70 degrees temp outside, how long does on average takes to heat the pool to 84 degrees? I am trying to get a sense if I want to use the pool the day after, if it is ok to turn the heat pump the day before or if I need at least a couple of days.

Thanks for your help.

 

[FamilyGuy]

Heat pumps are not what you think they are my friend. What you describe is better suited to a gas heater even in our area. Depending how long you want to extend your season a solar heater might be just fine for your needs

 

[duraleigh]

to use it to heat the pool for some weekends only.

That's where a gas heater has the advantage....it will bring your pool temp up MUCH more quickly. If you were to heat the pool 24/7, then a heat pump would probably be a better choice.

 

[Arobeth]

How about running costs? I have heard that gas heaters are very expensive to run. Is this true?

 

[jblizzle]

Depends on your gas cost and how much you use it. If you were going to keep the pool warm all the time, then the heat pump would likely be a good bit cheaper to run than a gas heater. But if you only occasionally want to heat the pool for a limited time, then you are not really running the gas heater that much and thus the costs are not that high.

It takes 1 BTU to raise 1 lb of water by 1 degree.

For a 10k pool * 8.3 lbs/gallon * 10 degree temp rise you need 830,000 BTUs
Assuming 85% efficiency on a gas heater you would need ~ 1,000,000 BTUs to raise the pool by 10 degrees (maybe a little more as this does not account for losses to the pipes/ground/structure/air/etc).

1 cubic foot = ~ 1000 BTUs so you need ~1000 cubic feet of gas

1000 cubic feet of natural gas may cost ~$15

So for a little over $15 you could add 10 degrees to your pool and then you would have to continue to run to maintain the temperature against losses.

With a 400k heater, it would take ~2.5 hours to add 10 degrees. With a 250k heater, it would take ~4 hours to add 10 degrees.

Heat pumps do not add the heat as fast especially when the air temp drops, so you would have to run them longer to get the desired temp rise.

Now if you want to add a little heat all through the summer and in the shoulder seasons, but also want to add a lot of heat on occasion in the winter, then a solar heater could work for the summer and only need the gas heater when the temp drops.

 

[Arobeth]

Thank you very much for the detailed explanation