I may NEED a pool heater?

[Isaac-1]

Ok, guys I could make this a very long post, but I will try to keep things fairly short, and stick to the important facts.

First off the pool, 20x40 indoor 36,0000 gallon pool with roof mounted solar, the roof is being replaced this fall and along with it the solar is being upgraded (this has been in the works for the last year). The existing aged solar heat would extend the swim season by about 10-12 weeks from late March through mid October most years. The location is in Louisiana, climate roughly equal to Houston Texas for a nearby major city comparison (maybe a little cooler). I am hopeful that the replacement more modern solar heat system will extend the season by about 16+ weeks total (spring/fall). This creates a reasonably long swim season, and under normal conditions I would leave it at that. However this year I may NEED a heated pool in January - March, as I am recovering from a broken back. By my doctors current estimates I will be out of my brace part time and ready to start physical therapy, etc. around Christmas. According to the doctor ideally this would start with swimming and other in water exercise that would keep weight off my back, unfortunately the nearest physical therapist I have found with a heated pool is 70+ miles away. So you can see why I say I may NEED a heater this year.

Now back to those facts: Fuel options Propane or Electric (maybe Diesel Oil as I have a spare 450 gallon diesel tank, and would have to upgrade propane tank size considerably for this)? Jan - Feb highs are anywhere from upper 30's through upper 40's most of the time, with lows often above freezing, however in the last couple of winters we have had lows in the low teens for multiple days at a time, and lows in the 20's fairly common. From what I have read online heat pump units tend to work best with smaller temperature deltas, is this true, etc. This then leads to what would you suggest? (other than a 3 month tropical vacation)


thanks for the help

Ike

 

[Ranger987]

In my opinion, your options are as follows:

Gas (LP or NG) - The fossil fuel heaters may be your best option, as they offer rapid heat times & can be used year round and are available in LP or Natural Gas. I'm not sure if anyone still makes an oil-fired heater for residential pools. I haven't seen one in many years. There are units available from Jandy & Rheem which offer up to 94% efficiency, but the purchase price goes way up for these. Most electronic ignition, Low Nox models are around 84% efficiency, reduced emissions and work extremely well. Induced draft models incorporate a fan to control combustion & maintain maximum efficiency. I recommend the LowNox as they tend to be far more reliable than models with standing pilot lights.

Heat Pump - The heat pump is the most efficient of the options, but generally speaking they cannot transfer enough heat when ambient air temperature drops below 45-50F. They also tend to be a little slow, but will maintain heat just fine. Will likely require 50-60 amp service for the heat pump alone. You can also purchase a Heat pump which incorporates a chiller, to cool the water during summer heat. These tend to be most expensive, but offer the greater efficiency. If it weren't for the low winter temps you mention, this would be my recommendation.

Electric - Heating elements - Inexpensive initial cost, very slow & very expensive to operate. I don't recommend these on anything larger than a hot tub/spa.

Many opionions exist on these different options, but given the winter air temperatures you mention, the size of your indoor pool, I think your solar, along with a gas heater is my recommendation, if you do have to add a heater. Since your pool is indoors, a 250,000btu model should be able to keep up with maintaining the water temperature.

 

[Poolschoolgrad]

Ike

We live in a climate very much like what you describe.
Our Rheem/Raypak heatpump can maintain comfortable water temperatures with a solar cover as long as the air temperatures are at least in the 50's.

For year-round heating, a gas heater will be your best option. One of our neighbors has an LP gas heater and it heats the water much quicker than our heatpump, however, the cost of operation is much higher.

Here are a couple of links provided by the US Department Of Energy that show comparable cost for each type of heater.
Please note the substantial savings when using a cover

http://www.energysavers.gov/your_home/w ... opic=13220

http://www.energysavers.gov/your_home/w ... opic=13180

 

[Isaac-1]

thanks for the replies, I will continue to investigate my options.

Ike

 

[learthur]

For the long term, I think expanding your solar heater surface area would be the first best choice. Then if you still want a heater, consider the heat pump. I have a friend in Houston who just installed one last spring. He hasn't gone through the cold DEC, JAN months yet with it, but he only has a 18,000 gal pool also.

You really need to cover your pool with a solar blanket and the heat pump choice may be problematic since you have such a large pool. You may need 2 heat pumps for a pool this size and they still won't work well below 55 degrees.

I have a NG heater on my pool and I have heated it during the coldest winter months. The NG bill was $800! for one month. That was probably $200 for my house heat and $600 for the pool heat.

Don't take this the wrong way, but I don't think you NEED a heater in January. I think you are using your medical condition to rationalize a heater. Physical Therapists are very good at coming up with exercise regimens that don't require a pool. There are lots of options besides a pool for a couple months until things warm up a bit. Sorry to be so blunt but I have a little experience in what I say.

Good luck....and think about making your solar bigger if possible. Best use of your money in the long term.

Lee

 

[bk406]

I have a heat pump so i do have some experience with them. It will not heat your pool once the temps fall below 54-50 degrees. It just wont. I'm actually getting an LP heater this spring since I'm not happy with the heat pump in early to mid spring and in September. If you want to heat the pool during the winter, gas is your best bet.
Issac has an indoor pool, so i doubt the cost to heat it would compare to an outdoor pool in the winter.
For a propane heater that is around 300,000 BTU, you will need a 200 gallon tank. You could always get a bigger one, but you dont want anything smaller than 200 gallons.

 

[Ranger987]

I 2nd what bk says. I've worked with many homeowners who were sold a heat pump for "year round heating". They were very disappointed when it would not do the job when air temps drop. There has been more than one lawsuit over this. It's often claimed that they will work down to 35, but there is not enough heat in the air to transfer into the water. Since his pool is indoors, he won't really need the solar blanket, as he's likely maintaining his indoor air temp around 80. Maximize the solar & add a gas heater for supplemental.

As swimming is one of the best exercises known, I think it's great that therapists to recommend swimming therapy. It's great for the body and the mind. A nice warm pool in winter beats the heck out of a treadmill or stationary bike.

 

[Isaac-1]

Thanks again for all the replies. I think the thing that may make the most sense is to target a system to allow for a mid Feb. swim season date, and hope for a mild January given the economic realities for Propane, and the limited performance of heat pumps. I have a somewhat important business trip scheduled in first part of January to southern California, the resort appears to have multiple swimming pools, etc. If my back is up to being crammed into an airline seat for the 4-5 hours to fly there I may try to extend the trip by a day or two and use my free time lounging in the pool just to see how being in a pool does to help allow for range of motion, etc. After that I will decide how much extending a early swim season is worth to me. A lot also depends on how my back is doing when I get out of this brace around Christmas, just in the last few days I have noticed a considerable improvement in my overall level of pain (I have only needed 1 pain pill since the weekend, although being up now at 4 am, I am giving strong thought to a second, I think I may have spent too much time yesterday sitting up at a desk, etc.), and level of range of movement.

Ike